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tcsh


NAME
     tcsh - C shell with file name completion  and  command  line
     editing

SYNOPSIS
     tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
     tcsh -l

DESCRIPTION
     tcsh is an enhanced but completely compatible version of the
     Berkeley  UNIX  C  shell,  csh(1).  It is a command language
     interpreter usable both as an interactive login shell and  a
     shell  script command processor.  It includes a command-line
     editor (see The command-line editor), programmable word com-
     pletion  (see  Completion  and listing), spelling correction
     (see Spelling correction), a history mechanism (see  History
     substitution),  job  control (see Jobs) and a C-like syntax.
     The NEW FEATURES section  describes  major  enhancements  of
     tcsh  over csh(1).  Throughout this manual, features of tcsh
     not found in most csh(1) implementations (specifically,  the
     4.4BSD  csh)  are labeled with `(+)', and features which are
     present in csh(1) but not  usually  documented  are  labeled
     with `(u)'.

  Argument list processing
     If the first argument (argument 0) to the shell is `-'  then
     it is a login shell.  A login shell can be also specified by
     invoking the shell with the -l flag as the only argument.

     The rest of the flag arguments are interpreted as follows:

     -b  Forces a ``break'' from option processing,  causing  any
         further  shell  arguments  to  be  treated as non-option
         arguments.  The remaining arguments will not  be  inter-
         preted  as  shell  options.   This  may  be used to pass
         options to a shell script without confusion or  possible
         subterfuge.  The shell will not run a set-user ID script
         without this option.

     -c  Commands are read from  the  following  argument  (which
         must  be present, and must be a single argument), stored
         in the command shell variable for  reference,  and  exe-
         cuted.   Any  remaining arguments are placed in the argv
         shell variable.

     -d  The shell loads the directory stack from  ~/.cshdirs  as
         described  under Startup and shutdown, whether or not it
         is a login shell. (+)

     -Dname[=value]
         Sets the environment variable name to value.  (Domain/OS
         only) (+)

     -e  The shell exits if any invoked command terminates abnor-
         mally or yields a non-zero exit status.

     -f  The shell ignores ~/.tcshrc, and thus starts faster.

     -F  The shell uses fork(2)  instead  of  vfork(2)  to  spawn
         processes. (Convex/OS only) (+)

     -i  The shell is interactive and prompts for  its  top-level
         input,  even if it appears to not be a terminal.  Shells
         are interactive without this option if their inputs  and
         outputs are terminals.

     -l  The shell is a login shell.  Applicable only  if  -l  is
         the only flag specified.

     -m  The shell loads ~/.tcshrc even if it does not belong  to
         the  effective  user.  Newer versions of su(1M) can pass
         -m to the shell. (+)

     -n  The shell parses commands but  does  not  execute  them.
         This aids in debugging shell scripts.

     -q  The shell accepts  SIGQUIT  (see  Signal  handling)  and
         behaves  when  it is used under a debugger.  Job control
         is disabled. (u)

     -s  Command input is taken from the standard input.

     -t  The shell reads and executes a single line of input.   A
         `\' may be used to escape the newline at the end of this
         line and continue onto another line.

     -v  Sets the verbose shell variable, so that  command  input
         is echoed after history substitution.

     -x  Sets the echo  shell  variable,  so  that  commands  are
         echoed immediately before execution.

     -V  Sets the verbose shell variable  even  before  executing
         ~/.tcshrc.

     -X  Is to -x as -V is to -v.

     After processing of flag arguments, if arguments remain  but
     none  of the -c, -i, -s, or -t options were given, the first
     argument is taken as the name of  a  file  of  commands,  or
     ``script'',  to  be executed.  The shell opens this file and
     saves its name for possible resubstitution by `$0'.  Because
     many  systems use either the standard version 6 or version 7
     shells whose shell scripts  are  not  compatible  with  this
     shell,  the  shell uses such a `standard' shell to execute a
     script whose first character is not a `#', i.e.,  that  does
     not start with a comment.

     Remaining arguments are placed in the argv shell variable.

  Startup and shutdown
     A login shell begins by executing commands from  the  system
     files  /etc/.cshrc  and  /etc/.login.  It then executes com-
     mands from  files  in  the  user's  home  directory:   first
     ~/.tcshrc  (+) or, if ~/.tcshrc is not found, ~/.cshrc, then
     ~/.history (or the value of the  histfile  shell  variable),
     then  ~/.login,  and finally ~/.cshdirs (or the value of the
     dirsfile  shell  variable)  (+).    The   shell   may   read
     /etc/csh.login  before  instead  of  after  /etc/.cshrc, and
     ~/.login before instead of after ~/.tcshrc or  ~/.cshrc  and
     ~/.history,  if so compiled; see the version shell variable.
     (+)

     Non-login shells read  only  /etc/.cshrc  and  ~/.tcshrc  or
     ~/.cshrc on startup.

     For   examples   of   startup    files,    please    consult
     http://tcshrc.sourceforge.net.

     Commands like stty(1) and tset(1B), which need be  run  only
     once  per  login,  usually go in one's ~/.login file.  Users
     who need to use the same set of files with both  csh(1)  and
     tcsh can have only a ~/.cshrc which checks for the existence
     of the tcsh shell variable (q.v.) before using tcsh-specific
     commands,  or can have both a ~/.cshrc and a ~/.tcshrc which
     sources (see the builtin command)  ~/.cshrc.   The  rest  of
     this  manual  uses  `~/.tcshrc'  to  mean  `~/.tcshrc or, if
     ~/.tcshrc is not found, ~/.cshrc'.

     In the normal case, the shell begins reading  commands  from
     the terminal, prompting with `> '.  (Processing of arguments
     and the use of the shell to process files containing command
     scripts  are described later.)  The shell repeatedly reads a
     line of command input, breaks it into words,  places  it  on
     the  command  history list, parses it and executes each com-
     mand in the line.

     One can log out by typing `^D' on an empty line, `logout' or
     `login'  or  via  the  shell's autologout mechanism (see the
     autologout shell variable).  When a login  shell  terminates
     it sets the logout shell variable to `normal' or `automatic'
     as  appropriate,  then  executes  commands  from  the  files
     /etc/csh.logout  and  ~/.logout.   The shell may drop DTR on
     logout if so compiled; see the version shell variable.

     The names of the system login and  logout  files  vary  from
     system  to  system  for  compatibility with different csh(1)
     variants; see FILES.

  Editing
     We first describe The command-line editor.   The  Completion
     and  listing  and  Spelling correction sections describe two
     sets of functionality that are implemented  as  editor  com-
     mands  but which deserve their own treatment.  Finally, Edi-
     tor  commands  lists  and  describes  the  editor   commands
     specific to the shell and their default bindings.

  The command-line editor (+)
     Command-line input can be edited using  key  sequences  much
     like those used in GNU Emacs or vi(1).  The editor is active
     only when the edit shell variable is set,  which  it  is  by
     default  in  interactive  shells.   The  bindkey builtin can
     display and change key bindings.  Emacs-style  key  bindings
     are  used  by  default (unless the shell was compiled other-
     wise; see the  version  shell  variable),  but  bindkey  can
     change the key bindings to vi-style bindings en masse.

     The shell always binds the arrow keys  (as  defined  in  the
     TERMCAP environment variable) to

         down    down-history
         up      up-history
         left    backward-char
         right   forward-char

     unless doing so would alter another  single-character  bind-
     ing.   One  can  set  the  arrow key escape sequences to the
     empty string with settc  to  prevent  these  bindings.   The
     ANSI/VT100 sequences for arrow keys are always bound.

     Other key bindings are, for the most part,  what  Emacs  and
     vi(1)  users  would  expect  and  can easily be displayed by
     bindkey, so there is no need to list them  here.   Likewise,
     bindkey  can  list the editor commands with a short descrip-
     tion of each.

     Note that editor commands do not have the same notion  of  a
     ``word''  as does the shell.  The editor delimits words with
     any non-alphanumeric characters not in  the  shell  variable
     wordchars,  while  the  shell recognizes only whitespace and
     some of the characters with special meanings to  it,  listed
     under Lexical structure.

  Completion and listing (+)
     The shell is often able  to  complete  words  when  given  a
     unique  abbreviation.   Type part of a word (for example `ls
     /usr/lost') and hit the tab key  to  run  the  complete-word
     editor   command.    The   shell   completes   the  filename
     `/usr/lost' to `/usr/lost+found/', replacing the  incomplete
     word  with the complete word in the input buffer.  (Note the
     terminal `/'; completion adds a `/' to the end of  completed
     directories and a space to the end of other completed words,
     to speed typing and provide a visual indicator of successful
     completion.   The  addsuffix  shell variable can be unset to
     prevent   this.)    If   no   match   is   found    (perhaps
     `/usr/lost+found'  doesn't  exist), the terminal bell rings.
     If  the  word  is  already  complete  (perhaps  there  is  a
     `/usr/lost' on your system, or perhaps you were thinking too
     far ahead and typed the whole thing) a `/' or space is added
     to the end if it isn't already there.

     Completion works anywhere in the line, not at just the  end;
     completed  text  pushes  the  rest of the line to the right.
     Completion in the middle of a word often results in leftover
     characters  to  the  right  of  the  cursor  that need to be
     deleted.

     Commands and variables can be completed  in  much  the  same
     way.   For  example, typing `em[tab]' would complete `em' to
     `emacs' if emacs were the only command on your system begin-
     ning with `em'.  Completion can find a command in any direc-
     tory in path or if given  a  full  pathname.   Typing  `echo
     $ar[tab]'  would complete `$ar' to `$argv' if no other vari-
     able began with `ar'.

     The shell parses the input buffer to determine  whether  the
     word you want to complete should be completed as a filename,
     command or variable.  The first word in the buffer  and  the
     first  word  following  `;', `|', `|&', `&&' or `||' is con-
     sidered to be a command.  A word beginning with `$' is  con-
     sidered  to be a variable.  Anything else is a filename.  An
     empty line is `completed' as a filename.

     You can list the possible completions of a word at any  time
     by  typing `^D' to run the delete-char-or-list-or-eof editor
     command.  The shell lists the possible completions using the
     ls-F  builtin (q.v.)  and reprints the prompt and unfinished
     command line, for example:

         > ls /usr/l[^D]
         lbin/       lib/        local/      lost+found/
         > ls /usr/l

     If the autolist shell variable is set, the shell  lists  the
     remaining choices (if any) whenever completion fails:

         > set autolist
         > nm /usr/lib/libt[tab]
         libtermcap.a@ libtermlib.a@
         > nm /usr/lib/libterm

     If autolist is set to `ambiguous', choices are  listed  only
     when completion fails and adds no new characters to the word
     being completed.

     A filename to be completed can contain variables,  your  own
     or  others'  home  directories  abbreviated  with  `~'  (see
     Filename substitution) and directory stack entries  abbrevi-
     ated with `=' (see Directory stack substitution).  For exam-
     ple,

         > ls ~k[^D]
         kahn    kas     kellogg
         > ls ~ke[tab]
         > ls ~kellogg/

     or

         > set local = /usr/local
         > ls $lo[tab]
         > ls $local/[^D]
         bin/ etc/ lib/ man/ src/
         > ls $local/

     Note that variables can also be expanded explicitly with the
     expand-variables editor command.

     delete-char-or-list-or-eof lists at  only  the  end  of  the
     line; in the middle of a line it deletes the character under
     the cursor and on an empty line  it  logs  one  out  or,  if
     ignoreeof is set, does nothing.  `M-^D', bound to the editor
     command list-choices, lists  completion  possibilities  any-
     where on a line, and list-choices (or any one of the related
     editor commands that do or don't  delete,  list  and/or  log
     out,  listed  under delete-char-or-list-or-eof) can be bound
     to `^D' with the bindkey builtin command if so desired.

     The complete-word-fwd and complete-word-back editor commands
     (not  bound  to any keys by default) can be used to cycle up
     and down through the list of possible completions, replacing
     the current word with the next or previous word in the list.

     The shell variable fignore can be set to a list of  suffixes
     to be ignored by completion.  Consider the following:

         > ls
         Makefile        condiments.h~   main.o          side.c
         README          main.c          meal            side.o
         condiments.h    main.c~
         > set fignore = (.o \~)
         > emacs ma[^D]
         main.c   main.c~  main.o
         > emacs ma[tab]
         > emacs main.c

     `main.c~' and `main.o' are ignored by  completion  (but  not
     listing),  because  they  end  in suffixes in fignore.  Note
     that a `\' was needed in front of `~'  to  prevent  it  from
     being expanded to home as described under Filename substitu-
     tion.  fignore is ignored if only one completion  is  possi-
     ble.

     If the complete shell variable is set to `enhance',  comple-
     tion  1)  ignores case and 2) considers periods, hyphens and
     underscores (`.', `-' and `_') to  be  word  separators  and
     hyphens  and  underscores  to be equivalent.  If you had the
     following files

         comp.lang.c      comp.lang.perl   comp.std.c++
         comp.lang.c++    comp.std.c

     and typed `mail -f c.l.c[tab]', it  would  be  completed  to
     `mail  -f  comp.lang.c', and ^D would list `comp.lang.c' and
     `comp.lang.c++'.    `mail   -f   c..c++[^D]'   would    list
     `comp.lang.c++' and `comp.std.c++'.  Typing `rm a--file[^D]'
     in the following directory

         A_silly_file    a-hyphenated-file    another_silly_file

     would list all three files,  because  case  is  ignored  and
     hyphens  and  underscores are equivalent.  Periods, however,
     are not equivalent to hyphens or underscores.

     Completion and listing are affected by several  other  shell
     variables:   recexact can be set to complete on the shortest
     possible unique match, even if more typing might result in a
     longer match:

         > ls
         fodder   foo      food     foonly
         > set recexact
         > rm fo[tab]

     just beeps, because `fo' could expand to `fod' or `foo', but
     if we type another `o',

         > rm foo[tab]
         > rm foo

     the completion completes on `foo', even  though  `food'  and
     `foonly'  also  match.   autoexpand  can  be  set to run the
     expand-history  editor  command   before   each   completion
     attempt, autocorrect can be set to spelling-correct the word
     to be completed (see Spelling correction) before  each  com-
     pletion  attempt and correct can be set to complete commands
     automatically after one hits `return'.  matchbeep can be set
     to  make  completion beep or not beep in a variety of situa-
     tions, and nobeep can be set to never beep at  all.   nostat
     can  be  set  to  a list of directories and/or patterns that
     match directories to prevent the completion  mechanism  from
     stat(2)ing  those  directories.  listmax and listmaxrows can
     be set to limit the number of items and rows  (respectively)
     that      are      listed      without     asking     first.
     recognize_only_executables can be set to make the shell list
     only  executables  when  listing  commands,  but it is quite
     slow.

     Finally, the complete builtin command can be  used  to  tell
     the  shell  how to complete words other than filenames, com-
     mands and variables.  Completion and listing do not work  on
     glob-patterns (see Filename substitution), but the list-glob
     and expand-glob editor commands perform equivalent functions
     for glob-patterns.

  Spelling correction (+)
     The shell can sometimes correct the spelling  of  filenames,
     commands  and variable names as well as completing and list-
     ing them.

     Individual words can be spelling-corrected with  the  spell-
     word  editor  command (usually bound to M-s and M-S) and the
     entire input buffer with spell-line (usually bound to  M-$).
     The  correct  shell  variable can be set to `cmd' to correct
     the command name or `all' to correct the  entire  line  each
     time  return is typed, and autocorrect can be set to correct
     the word to be completed before each completion attempt.

     When spelling correction is invoked in any of these ways and
     the  shell  thinks  that  any  part  of  the command line is
     misspelled, it prompts with the corrected line:

         > set correct = cmd
         > lz /usr/bin
         CORRECT>ls /usr/bin (y|n|e|a)?

     One can answer `y' or space to execute the  corrected  line,
     `e'  to  leave  the uncorrected command in the input buffer,
     `a' to abort the command as if `^C' had been hit,  and  any-
     thing else to execute the original line unchanged.

     Spelling correction recognizes user-defined completions (see
     the  complete builtin command).  If an input word in a posi-
     tion for which a completion is defined resembles a  word  in
     the   completion   list,  spelling  correction  registers  a
     misspelling and suggests the latter word  as  a  correction.
     However,  if the input word does not match any of the possi-
     ble completions for that position, spelling correction  does
     not register a misspelling.

     Like completion, spelling correction works anywhere  in  the
     line, pushing the rest of the line to the right and possibly
     leaving extra characters to the right of the cursor.

     Beware: spelling correction is not guaranteed  to  work  the
     way  one  intends, and is provided mostly as an experimental
     feature.  Suggestions and improvements are welcome.

  Editor commands (+)
     `bindkey' lists key bindings  and  `bindkey  -l'  lists  and
     briefly  describes  editor commands.  Only new or especially
     interesting editor commands are  described  here.   See  the
     Emacs  documentation  and  vi(1)  for  descriptions  of each
     editor's key bindings.

     The character or characters to which each command  is  bound
     by  default  is  given in parentheses.  `^character' means a
     control character and `M-character' a meta character,  typed
     as  escape-character  on terminals without a meta key.  Case
     counts, but commands that are bound to  letters  by  default
     are  bound to both lower- and uppercase letters for conveni-
     ence.

     complete-word (tab)
             Completes a word as described under  Completion  and
             listing.

     complete-word-back (not bound)
             Like complete-word-fwd, but steps up from the end of
             the list.

     complete-word-fwd (not bound)
             Replaces the current word with the first word in the
             list  of  possible  completions.  May be repeated to
             step down through the list.  At the end of the list,
             beeps and reverts to the incomplete word.

     complete-word-raw (^X-tab)
             Like complete-word, but ignores user-defined comple-
             tions.

     copy-prev-word (M-^_)
             Copies the previous word in the  current  line  into
             the input buffer.  See also insert-last-word.

     dabbrev-expand (M-/)
             Expands the current word to the most recent  preced-
             ing  one  for  which  the  current is a leading sub-
             string, wrapping around the history list  (once)  if
             necessary.   Repeating  dabbrev-expand  without  any
             intervening typing changes to the next previous word
             etc.,  skipping identical matches much like history-
             search-backward does.

     delete-char (not bound)
             Deletes the character under the  cursor.   See  also
             delete-char-or-list-or-eof.

     delete-char-or-eof (not bound)
             Does delete-char if there is a character  under  the
             cursor  or  end-of-file  on an empty line.  See also
             delete-char-or-list-or-eof.

     delete-char-or-list (not bound)
             Does delete-char if there is a character  under  the
             cursor  or list-choices at the end of the line.  See
             also delete-char-or-list-or-eof.

     delete-char-or-list-or-eof (^D)
             Does delete-char if there is a character  under  the
             cursor,  list-choices at the end of the line or end-
             of-file on an empty line.  See also those three com-
             mands,  each of which does only a single action, and
             delete-char-or-eof,  delete-char-or-list  and  list-
             or-eof,  each  of  which does a different two out of
             the three.

     down-history (down-arrow, ^N)
             Like up-history, but steps  down,  stopping  at  the
             original input line.

     end-of-file (not bound)
             Signals an end of file, causing the  shell  to  exit
             unless the ignoreeof shell variable (q.v.) is set to
             prevent this.  See also delete-char-or-list-or-eof.

     expand-history (M-space)
             Expands history substitutions in the  current  word.
             See  History  substitution.   See  also magic-space,
             toggle-literal-history  and  the  autoexpand   shell
             variable.

     expand-glob (^X-*)
             Expands the glob-pattern to the left of the  cursor.
             See Filename substitution.

     expand-line (not bound)
             Like expand-history, but expands  history  substitu-
             tions in each word in the input buffer,

     expand-variables (^X-$)
             Expands the variable to the left of the cursor.  See
             Variable substitution.

     history-search-backward (M-p, M-P)
             Searches backwards through the history  list  for  a
             command  beginning  with the current contents of the
             input buffer up to the cursor and copies it into the
             input  buffer.   The  search  string  may be a glob-
             pattern (see Filename substitution) containing  `*',
             `?', `[]' or `{}'.  up-history and down-history will
             proceed from the appropriate point  in  the  history
             list.   Emacs  mode  only.  See also history-search-
             forward and i-search-back.

     history-search-forward (M-n, M-N)
             Like history-search-backward, but searches forward.

     i-search-back (not bound)
             Searches  backward   like   history-search-backward,
             copies  the  first  match into the input buffer with
             the cursor positioned at the end of the pattern, and
             prompts  with  `bck:  '  and the first match.  Addi-
             tional characters may be typed to extend the search,
             i-search-back  may  be  typed  to continue searching
             with the same pattern, wrapping around  the  history
             list if necessary, (i-search-back must be bound to a
             single character for this to work)  or  one  of  the
             following special characters may be typed:

                 ^W      Appends the rest of the word  under  the
                         cursor to the search pattern.
                        char)
                 delete (or any character  bound  to  backward-
                         delete-
                         Undoes the effect of the last  character
                         typed  and  deletes a character from the
                         search pattern if appropriate.
                 ^G      If the previous search  was  successful,
                         aborts  the entire search.  If not, goes
                         back to the last successful search.
                 escape  Ends the  search,  leaving  the  current
                         line in the input buffer.

             Any other character not bound to self-insert-command
             terminates  the  search, leaving the current line in
             the input buffer, and is then interpreted as  normal
             input.   In particular, a carriage return causes the
             current line to be executed.  Emacs mode only.   See
             also i-search-fwd and history-search-backward.

     i-search-fwd (not bound)
             Like i-search-back, but searches forward.

     insert-last-word (M-_)
             Inserts the last word of  the  previous  input  line
             (`!$')  into  the input buffer.  See also copy-prev-
             word.

     list-choices (M-^D)
             Lists completion possibilities  as  described  under
             Completion  and  listing.   See also delete-char-or-
             list-or-eof and list-choices-raw.

     list-choices-raw (^X-^D)
             Like list-choices, but ignores user-defined  comple-
             tions.

     list-glob (^X-g, ^X-G)
             Lists (via the ls-F builtin) matches  to  the  glob-
             pattern  (see  Filename substitution) to the left of
             the cursor.

     list-or-eof (not bound)
             Does list-choices or end-of-file on an  empty  line.
             See also delete-char-or-list-or-eof.

     magic-space (not bound)
             Expands history substitutions in the  current  line,
             like  expand-history,  and  appends a space.  magic-
             space is designed to be bound to the space bar,  but
             is not bound by default.

     normalize-command (^X-?)
             Searches for the current word in PATH and, if it  is
             found, replaces it with the full path to the execut-
             able.  Special characters are quoted.   Aliases  are
             expanded  and quoted but commands within aliases are
             not.  This command is useful with commands that take
             commands as arguments, e.g., `dbx' and `sh -x'.

     normalize-path (^X-n, ^X-N)
             Expands the current  word  as  described  under  the
             `expand' setting of the symlinks shell variable.

     overwrite-mode (unbound)
             Toggles between input and overwrite modes.

     run-fg-editor (M-^Z)
             Saves the current input line and looks for a stopped
             job  with  a name equal to the last component of the
             file name part of the EDITOR or  VISUAL  environment
             variables,  or, if neither is set, `ed' or `vi'.  If
             such a job is found, it is restarted as if `fg %job'
             had  been  typed.   This  is used to toggle back and
             forth between an editor and the shell easily.   Some
             people bind this command to `^Z' so they can do this
             even more easily.

     run-help (M-h, M-H)
             Searches for documentation on the  current  command,
             using  the  same  notion of `current command' as the
             completion routines, and prints it.  There is no way
             to  use a pager; run-help is designed for short help
             files.  If the special alias helpcommand is defined,
             it  is run with the command name as a sole argument.
             Else,  documentation  should  be  in  a  file  named
             command.help,  command.1,  command.6,  command.8  or
             command, which should be in one of  the  directories
             listed  in the HPATH environment variable.  If there
             is more  than  one  help  file  only  the  first  is
             printed.

     self-insert-command (text characters)
             In insert mode  (the  default),  inserts  the  typed
             character  into  the  input line after the character
             under the cursor.  In overwrite mode,  replaces  the
             character under the cursor with the typed character.
             The input mode is normally preserved between  lines,
             but  the  inputmode  shell  variable  can  be set to
             `insert' or `overwrite' to put the  editor  in  that
             mode  at  the  beginning  of  each  line.   See also
             overwrite-mode.

     sequence-lead-in (arrow prefix, meta prefix, ^X)
             Indicates that the following characters are part  of
             a  multi-key  sequence.   Binding  a  command  to  a
             multi-key sequence really creates two bindings:  the
             first  character  to  sequence-lead-in and the whole
             sequence to the command.   All  sequences  beginning
             with  a  character  bound  to  sequence-lead-in  are
             effectively bound to undefined-key unless  bound  to
             another command.

     spell-line (M-$)
             Attempts to correct the spelling of each word in the
             input  buffer,  like  spell-word,  but ignores words
             whose first character is one of  `-',  `!',  `^'  or
             `%',  or  which  contain  `\',  `*' or `?', to avoid
             problems with switches, substitutions and the  like.
             See Spelling correction.

     spell-word (M-s, M-S)
             Attempts to correct the spelling of the current word
             as described under Spelling correction.  Checks each
             component of a word which appears to be a pathname.

     toggle-literal-history (M-r, M-R)
             Expands or `unexpands' history substitutions in  the
             input  buffer.   See  also  expand-history  and  the
             autoexpand shell variable.

     undefined-key (any unbound key)
             Beeps.

     up-history (up-arrow, ^P)
             Copies the previous entry in the history  list  into
             the  input  buffer.   If  histlit  is  set, uses the
             literal form of the entry.  May be repeated to  step
             up through the history list, stopping at the top.

     vi-search-back (?)
             Prompts with `?' for a search string (which may be a
             glob-pattern,   as   with  history-search-backward),
             searches for it and copies it into the input buffer.
             The bell rings if no match is found.  Hitting return
             ends the search and leaves the  last  match  in  the
             input  buffer.   Hitting  escape ends the search and
             executes the match.  vi mode only.

     vi-search-fwd (/)
             Like vi-search-back, but searches forward.

     which-command (M-?)
             Does a which (see the  description  of  the  builtin
             command) on the first word of the input buffer.

  Lexical structure
     The shell splits input lines into words at blanks and  tabs.
     The special characters `&', `|', `;', `<', `>', `(', and `)'
     and the doubled characters `&&', `||',  `<<'  and  `>>'  are
     always separate words, whether or not they are surrounded by
     whitespace.

     When the shell's input is not a terminal, the character  `#'
     is  taken  to begin a comment.  Each `#' and the rest of the
     input line on which it appears is discarded  before  further
     parsing.

     A special character  (including  a  blank  or  tab)  may  be
     prevented from having its special meaning, and possibly made
     part of another word, by preceding it with a backslash (`\')
     or  enclosing  it  in single (`''), double (`"') or backward
     (``') quotes.  When not otherwise quoted a newline  preceded
     by  a  `\'  is equivalent to a blank, but inside quotes this
     sequence results in a newline.

     Furthermore, all Substitutions (see  below)  except  History
     substitution  can  be prevented by enclosing the strings (or
     parts of strings) in which they appear with single quotes or
     by  quoting  the  crucial character(s) (e.g., `$' or ``' for
     Variable substitution or Command substitution  respectively)
     with  `\'.   (Alias substitution is no exception: quoting in
     any way any character of a word for which an alias has  been
     defined  prevents  substitution of the alias.  The usual way
     of quoting an alias is to precede it with a backslash.) His-
     tory  substitution  is  prevented  by backslashes but not by
     single quotes.   Strings  quoted  with  double  or  backward
     quotes  undergo  Variable substitution and Command substitu-
     tion, but other substitutions are prevented.

     Text inside single or double quotes becomes  a  single  word
     (or  part of one).  Metacharacters in these strings, includ-
     ing blanks and tabs, do not form separate  words.   Only  in
     one  special  case  (see  Command  substitution below) can a
     double-quoted string yield parts  of  more  than  one  word;
     single-quoted  strings  never  do.  Backward quotes are spe-
     cial: they signal Command  substitution  (q.v.),  which  may
     result in more than one word.

     Quoting complex strings, particularly  strings  which  them-
     selves   contain   quoting  characters,  can  be  confusing.
     Remember that quotes need not be used as they are  in  human
     writing!   It  may  be easier to quote not an entire string,
     but only those parts of the string which need quoting, using
     different types of quoting to do so if appropriate.

     The backslash_quote shell variable (q.v.) can be set to make
     backslashes  always  quote  `\', `'', and `"'.  (+) This may
     make complex quoting tasks easier, but it can  cause  syntax
     errors in csh(1) scripts.

  Substitutions
     We now describe the various transformations the  shell  per-
     forms  on  the  input  in the order in which they occur.  We
     note in passing the data structures involved  and  the  com-
     mands  and  variables which affect them.  Remember that sub-
     stitutions can be prevented by quoting  as  described  under
     Lexical structure.

  History substitution
     Each command, or ``event'', input from the terminal is saved
     in  the history list.  The previous command is always saved,
     and the history shell variable can be set  to  a  number  to
     save  that many commands.  The histdup shell variable can be
     set to not save duplicate events  or  consecutive  duplicate
     events.

     Saved commands are numbered sequentially from 1 and  stamped
     with  the  time.   It  is not usually necessary to use event
     numbers, but the current event number can be  made  part  of
     the prompt by placing an `!' in the prompt shell variable.
     The shell actually saves history  in  expanded  and  literal
     (unexpanded)  forms.   If the histlit shell variable is set,
     commands that display and  store  history  use  the  literal
     form.

     The history builtin command can  print,  store  in  a  file,
     restore  and  clear  the  history  list at any time, and the
     savehist and histfile shell variables can be can be  set  to
     store  the  history list automatically on logout and restore
     it on login.

     History substitutions introduce words from the history  list
     into  the  input  stream, making it easy to repeat commands,
     repeat arguments of a previous command in the  current  com-
     mand,  or fix spelling mistakes in the previous command with
     little typing and a high degree of confidence.

     History substitutions begin with the  character  `!'.   They
     may  begin  anywhere  in  the  input stream, but they do not
     nest.  The `!' may be preceded by a `\' to prevent its  spe-
     cial  meaning;  for  convenience,  a `!' is passed unchanged
     when it is followed by a blank, tab, newline,  `='  or  `('.
     History  substitutions  also occur when an input line begins
     with `^'.   This  special  abbreviation  will  be  described
     later.   The  characters used to signal history substitution
     (`!' and `^') can be changed by setting the histchars  shell
     variable.  Any input line which contains a history substitu-
     tion is printed before it is executed.

     A history substitution may have an ``event  specification'',
     which  indicates the event from which words are to be taken,
     a ``word designator'', which selects particular  words  from
     the  chosen  event, and/or a ``modifier'', which manipulates
     the selected words.

     An event specification can be

         n       A number, referring to a particular event
         -n      An offset, referring to the event n  before  the
                 current event
         #       The current event.  This should  be  used  care-
                 fully  in  csh(1),  where  there is no check for
                 recursion.  tcsh allows 10 levels of  recursion.
                 (+)
         !       The previous event (equivalent to `-1')
         s       The most recent event whose  first  word  begins
                 with the string s
         ?s?     The most recent event which contains the  string
                 s.   The  second  `?'  can  be  omitted if it is
                 immediately followed by a newline.


     For example, consider this bit of someone's history list:

          9  8:30    nroff -man wumpus.man
         10  8:31    cp wumpus.man wumpus.man.old
         11  8:36    vi wumpus.man
         12  8:37    diff wumpus.man.old wumpus.man

     The commands are shown with their  event  numbers  and  time
     stamps.   The  current event, which we haven't typed in yet,
     is event 13.  `!11' and  `!-2'  refer  to  event  11.   `!!'
     refers  to  the previous event, 12.  `!!' can be abbreviated
     `!' if it is followed by `:' (`:' is described below).  `!n'
     refers  to  event  9,  which begins with `n'.  `!?old?' also
     refers to event 12,  which  contains  `old'.   Without  word
     designators or modifiers history references simply expand to
     the entire event, so we might type `!cp' to  redo  the  copy
     command  or  `!!|more' if the `diff' output scrolled off the
     top of the screen.

     History references may be  insulated  from  the  surrounding
     text  with  braces if necessary.  For example, `!vdoc' would
     look for a command beginning with `vdoc', and, in this exam-
     ple,  not find one, but `!{v}doc' would expand unambiguously
     to `vi wumpus.mandoc'.  Even in  braces,  history  substitu-
     tions do not nest.

     (+) While csh(1) expands, for example, `!3d' to event 3 with
     the  letter  `d' appended to it, tcsh expands it to the last
     event beginning with `3d'; only completely numeric arguments
     are  treated  as  event  numbers.  This makes it possible to
     recall events beginning with numbers.  To expand `!3d' as in
     csh(1) say `!\3d'.

     To select words from  an  event  we  can  follow  the  event
     specification  by  a  `:'   and a designator for the desired
     words.  The words of an input line are numbered from 0,  the
     first (usually command) word being 0, the second word (first
     argument) being 1, etc.  The basic word designators are:

         0       The first (command) word
         n       The nth argument
         ^       The first argument, equivalent to `1'
         $       The last argument
         %       The word matched by an ?s? search
         x-y     A range of words
         -y      Equivalent to `0-y'
         *       Equivalent to `^-$', but returns nothing if  the
                 event contains only 1 word
         x*      Equivalent to `x-$'
         x-      Equivalent to `x*', but omitting the  last  word
                 (`$')

     Selected words are inserted into the command line  separated
     by  single  blanks.   For example, the `diff' command in the
     previous example might have been  typed  as  `diff  !!:1.old
     !!:1' (using `:1' to select the first argument from the pre-
     vious event) or `diff !-2:2 !-2:1' to select  and  swap  the
     arguments  from  the  `cp' command.  If we didn't care about
     the order of the `diff' we might have said `diff !-2:1-2' or
     simply `diff !-2:*'.  The `cp' command might have been writ-
     ten `cp wumpus.man !#:1.old', using  `#'  to  refer  to  the
     current  event.  `!n:- hurkle.man' would reuse the first two
     words  from  the  `nroff'  command  to   say   `nroff   -man
     hurkle.man'.

     The `:' separating the event  specification  from  the  word
     designator  can  be  omitted if the argument selector begins
     with a `^', `$', `*', `%' or `-'.  For example,  our  `diff'
     command might have been `diff !!^.old !!^' or, equivalently,
     `diff !!$.old !!$'.  However, if `!!' is abbreviated `!', an
     argument  selector beginning with `-' will be interpreted as
     an event specification.

     A history reference may have a word designator but no  event
     specification.   It  then  references  the previous command.
     Continuing our `diff' example, we  could  have  said  simply
     `diff  !^.old  !^'  or, to get the arguments in the opposite
     order, just `diff !*'.

     The word or words in a history reference can be  edited,  or
     ``modified'',  by  following  it with one or more modifiers,
     each preceded by a `:':

         h       Remove a trailing  pathname  component,  leaving
                 the head.
         t       Remove all leading pathname components,  leaving
                 the tail.
         r       Remove a filename extension `.xxx', leaving  the
                 root name.
         e       Remove all but the extension.
         u       Uppercase the first lowercase letter.
         l       Lowercase the first uppercase letter.
         s/l/r/  Substitute l for r.  l is simply a  string  like
                 r,  not a regular expression as in the eponymous
                 ed(1) command.  Any character may be used as the
                 delimiter  in place of `/'; a `\' can be used to
                 quote the delimiter inside l and r.  The charac-
                 ter  `&'  in  the  r  is replaced by l; `\' also
                 quotes `&'.  If l is empty (``''), the l from  a
                 previous  substitution  or the s from a previous
                 `?s?' event specification is used.  The trailing
                 delimiter  may  be  omitted if it is immediately
                 followed by a newline.
         &       Repeat the previous substitution.
         g       Apply the following modifier once to each word.
         a (+)   Apply the following modifier as  many  times  as
                 possible  to  a single word.  `a' and `g' can be
                 used together to apply a modifier globally.   In
                 the  current  implementation,  using the `a' and
                 `s' modifiers together can lead to  an  infinite
                 loop.   For example, `:as/f/ff/' will never ter-
                 minate.   This  behavior  might  change  in  the
                 future.
         p       Print the new command line but  do  not  execute
                 it.
         q       Quote the substituted words, preventing  further
                 substitutions.
         x       Like q, but break into words at blanks, tabs and
                 newlines.

     Modifiers are applied to  only  the  first  modifiable  word
     (unless  `g'  is  used).   It  is an error for no word to be
     modifiable.

     For example, the `diff' command might have been  written  as
     `diff  wumpus.man.old  !#^:r',  using  `:r' to remove `.old'
     from the first argument on the same line (`!#^').  We  could
     say  `echo  hello out there', then `echo !*:u' to capitalize
     `hello', `echo !*:au' to say it out loud, or  `echo  !*:agu'
     to  really  shout.   We  might  follow `mail -s "I forgot my
     password" rot' with `!:s/rot/root' to correct  the  spelling
     of  `root'  (but  see  Spelling  correction  for a different
     approach).

     There is a special  abbreviation  for  substitutions.   `^',
     when  it  is  the  first  character  on  an  input  line, is
     equivalent to `!:s^'.  Thus we might have  said  `^rot^root'
     to  make  the  spelling  correction in the previous example.
     This is the only history substitution which does not  expli-
     citly begin with `!'.

     (+) In csh as such, only one modifier may be applied to each
     history  or  variable expansion.  In tcsh, more than one may
     be used, for example

         % mv wumpus.man /usr/man/man1/wumpus.1
         % man !$:t:r
         man wumpus

     In csh, the result would be  `wumpus.1:r'.   A  substitution
     followed  by  a  colon may need to be insulated from it with
     braces:

         > mv a.out /usr/games/wumpus
         > setenv PATH !$:h:$PATH
         Bad ! modifier: $.
         > setenv PATH !{-2$:h}:$PATH
         setenv PATH /usr/games:/bin:/usr/bin:.

     The first attempt would succeed in csh but  fails  in  tcsh,
     because tcsh expects another modifier after the second colon
     rather than `$'.

     Finally, history can be accessed through the editor as  well
     as  through  the  substitutions just described.  The up- and
     down-history,  history-search-backward  and   -forward,   i-
     search-back  and  -fwd,  vi-search-back and -fwd, copy-prev-
     word and insert-last-word editor commands search for  events
     in  the  history  list  and copy them into the input buffer.
     The toggle-literal-history editor command  switches  between
     the expanded and literal forms of history lines in the input
     buffer.  expand-history and expand-line expand history  sub-
     stitutions  in  the  current  word  and  in the entire input
     buffer respectively.

  Alias substitution
     The shell maintains a list of  aliases  which  can  be  set,
     unset  and printed by the alias and unalias commands.  After
     a command line is parsed into simple commands (see Commands)
     the first word of each command, left-to-right, is checked to
     see if it has an alias.  If so, the first word  is  replaced
     by the alias.  If the alias contains a history reference, it
     undergoes History substitution (q.v.) as though the original
     command were the previous input line.  If the alias does not
     contain a history  reference,  the  argument  list  is  left
     untouched.

     Thus if the alias for `ls' were  `ls  -l'  the  command  `ls
     /usr'  would  become  `ls  -l  /usr', the argument list here
     being undisturbed.  If the alias for `lookup' were `grep  !^
     /etc/passwd'  then  `lookup  bill'  would  become `grep bill
     /etc/passwd'.  Aliases  can  be  used  to  introduce  parser
     metasyntax.   For  example,  `alias  print  'pr  \!* | lpr''
     defines a ``command'' (`print') which pr(1)s  its  arguments
     to the line printer.

     Alias substitution is repeated until the first word  of  the
     command  has  no  alias.   If an alias substitution does not
     change the first word (as in the  previous  example)  it  is
     flagged  to  prevent  a  loop.  Other loops are detected and
     cause an error.

     Some aliases are referred  to  by  the  shell;  see  Special
     aliases.

  Variable substitution
     The shell maintains a list of variables, each of  which  has
     as  value a list of zero or more words.  The values of shell
     variables can be displayed and  changed  with  the  set  and
     unset  commands.   The  system  maintains  its  own  list of
     ``environment''  variables.   These  can  be  displayed  and
     changed with printenv, setenv and unsetenv.

     (+) Variables may be made read-only  with  `set  -r'  (q.v.)
     Read-only variables may not be modified or unset; attempting
     to do so will cause an error.  Once made read-only, a  vari-
     able  cannot  be  made  writable, so `set -r' should be used
     with caution.  Environment variables cannot  be  made  read-
     only.

     Some variables are set by the shell or referred  to  by  it.
     For  instance,  the argv variable is an image of the shell's
     argument list,  and  words  of  this  variable's  value  are
     referred to in special ways.  Some of the variables referred
     to by the shell are toggles; the shell does  not  care  what
     their  value  is,  only  whether  they  are set or not.  For
     instance, the verbose variable is a toggle which causes com-
     mand  input  to  be echoed.  The -v command line option sets
     this variable.  Special shell variables lists all  variables
     which are referred to by the shell.

     Other operations treat variables numerically.  The `@'  com-
     mand  permits  numeric  calculations to be performed and the
     result assigned to a variable.  Variable  values  are,  how-
     ever, always represented as (zero or more) strings.  For the
     purposes of numeric operations,  the  null  string  is  con-
     sidered  to  be zero, and the second and subsequent words of
     multi-word values are ignored.

     After the input line is aliased and parsed, and before  each
     command  is  executed,  variable  substitution  is performed
     keyed by `$' characters.  This expansion can be prevented by
     preceding  the  `$'  with  a `\' except within `"'s where it
     always occurs,  and  within  `''s  where  it  never  occurs.
     Strings  quoted  by  ``'  are interpreted later (see Command
     substitution below) so `$' substitution does not occur there
     until  later,  if at all.  A `$' is passed unchanged if fol-
     lowed by a blank, tab, or end-of-line.

     Input/output redirections  are  recognized  before  variable
     expansion, and are variable expanded separately.  Otherwise,
     the command name  and  entire  argument  list  are  expanded
     together.   It is thus possible for the first (command) word
     (to this point) to generate more than one word, the first of
     which becomes the command name, and the rest of which become
     arguments.

     Unless enclosed in  `"'  or  given  the  `:q'  modifier  the
     results  of  variable substitution may eventually be command
     and filename substituted.   Within  `"',  a  variable  whose
     value consists of multiple words expands to a (portion of a)
     single  word,  with  the  words  of  the  variable's   value
     separated by blanks.  When the `:q' modifier is applied to a
     substitution the variable will expand to multiple words with
     each  word  separated by a blank and quoted to prevent later
     command or filename substitution.

     The following metasequences  are  provided  for  introducing
     variable  values  into the shell input.  Except as noted, it
     is an error to reference a variable which is not set.

     $name
     ${name} Substitutes the words of the value of variable name,
             each  separated  by  a  blank.  Braces insulate name
             from following characters which would  otherwise  be
             part  of  it.  Shell variables have names consisting
             of up to 20  letters  and  digits  starting  with  a
             letter.   The  underscore  character is considered a
             letter.  If name is not a shell variable, but is set
             in the environment, then that value is returned (but
             `:' modifiers and the other forms  given  below  are
             not available in this case).
     $name[selector]
     ${name[selector]}
             Substitutes only the selected words from  the  value
             of name.  The selector is subjected to `$' substitu-
             tion and may consist  of  a  single  number  or  two
             numbers  separated  by  a  `-'.  The first word of a
             variable's value is  numbered  `1'.   If  the  first
             number of a range is omitted it defaults to `1'.  If
             the last member of a range is omitted it defaults to
             `$#name'.   The  selector `*' selects all words.  It
             is not an error for a  range  to  be  empty  if  the
             second argument is omitted or in range.
     $0      Substitutes the name of the file from which  command
             input is being read.  An error occurs if the name is
             not known.
     $number
     ${number}
             Equivalent to `$argv[number]'.
     $*      Equivalent  to  `$argv',  which  is  equivalent   to
             `$argv[*]'.

     The `:'  modifiers  described  under  History  substitution,
     except  for `:p', can be applied to the substitutions above.
     More than one may be used.  (+)  Braces  may  be  needed  to
     insulate  a  variable substitution from a literal colon just
     as with History  substitution  (q.v.);  any  modifiers  must
     appear within the braces.

     The following substitutions can not  be  modified  with  `:'
     modifiers.
     $?name
     ${?name}
             Substitutes the string `1' if name is set, `0' if it
             is not.
     $?0     Substitutes `1' if the  current  input  filename  is
             known,  `0' if it is not.  Always `0' in interactive
             shells.
     $#name
     ${#name}
             Substitutes the number of words in name.
     $#      Equivalent to `$#argv'.  (+)
     $%name
     ${%name}
             Substitutes the number of characters in name.  (+)
     $%number
     ${%number}
             Substitutes   the   number    of    characters    in
             $argv[number].  (+)
     $?      Equivalent to `$status'.  (+)
     $$      Substitutes the  (decimal)  process  number  of  the
             (parent) shell.
     $!      Substitutes the (decimal) process number of the last
             background process started by this shell.  (+)
     $_      Substitutes the command line  of  the  last  command
             executed.  (+)
     $<      Substitutes a line from the standard input, with  no
             further  interpretation  thereafter.  It can be used
             to read from the keyboard in a  shell  script.   (+)
             While csh always quotes $<, as if it were equivalent
             to `$<:q', tcsh does not.  Furthermore, when tcsh is
             waiting  for a line to be typed the user may type an
             interrupt to interrupt the sequence into  which  the
             line  is  to  be substituted, but csh does not allow
             this.

     The editor command expand-variables, normally bound to  `^X-
     $',  can  be  used  to interactively expand individual vari-
     ables.

  Command, filename and directory stack substitution
     The remaining substitutions are applied selectively  to  the
     arguments  of builtin commands.  This means that portions of
     expressions which are not evaluated  are  not  subjected  to
     these  expansions.   For  commands which are not internal to
     the shell, the command name is substituted  separately  from
     the  argument  list.   This  occurs  very late, after input-
     output redirection is performed, and in a child of the  main
     shell.

  Command substitution
     Command substitution is indicated by a command  enclosed  in
     ``'.  The output from such a command is broken into separate
     words at blanks, tabs and newlines, and null words are  dis-
     carded.   The output is variable and command substituted and
     put in place of the original string.

     Command substitutions  inside  double  quotes  (`"')  retain
     blanks  and tabs; only newlines force new words.  The single
     final newline does not force a new word in any case.  It  is
     thus  possible for a command substitution to yield only part
     of a word, even if the command outputs a complete line.

  Filename substitution
     If a word contains any of the characters `*',  `?',  `['  or
     `{'  or  begins with the character `~' it is a candidate for
     filename substitution, also  known  as  ``globbing''.   This
     word  is  then regarded as a pattern (``glob-pattern''), and
     replaced with an alphabetically sorted list  of  file  names
     which match the pattern.

     In matching filenames, the character `.' at the beginning of
     a  filename  or  immediately following a `/', as well as the
     character `/' must be matched explicitly.  The character `*'
     matches any string of characters, including the null string.
     The  character  `?'  matches  any  single  character.    The
     sequence `[...]' matches any one of the characters enclosed.
     Within `[...]',  a  pair  of  characters  separated  by  `-'
     matches any character lexically between the two.

     (+)  Some  glob-patterns  can  be  negated:   The   sequence
     `[^...]'  matches  any single character not specified by the
     characters and/or ranges of characters in the braces.

     An entire glob-pattern can also be negated with `^':

         > echo *
         bang crash crunch ouch
         > echo ^cr*
         bang ouch

     Glob-patterns which do not use `?', `*', or  `[]'  or  which
     use `{}' or `~' (below) are not negated correctly.

     The metanotation `a{b,c,d}e' is a  shorthand  for  `abe  ace
     ade'.       Left-to-right      order      is      preserved:
     `/usr/source/s1/{oldls,ls}.c'           expands           to
     `/usr/source/s1/oldls.c  /usr/source/s1/ls.c'.   The results
     of matches are sorted separately at a low level to  preserve
     this  order:   `../{memo,*box}'  might  expand  to  `../memo
     ../box ../mbox'.  (Note that `memo' was not sorted with  the
     results  of  matching `*box'.)  It is not an error when this
     construct expands to files which do not  exist,  but  it  is
     possible  to  get  an  error  from  a  command  to which the
     expanded list is passed.  This construct may be nested.   As
     a special case the words `{', `}' and `{}' are passed undis-
     turbed.

     The character `~' at the beginning of a filename  refers  to
     home  directories.  Standing alone, i.e., `~', it expands to
     the invoker's home directory as reflected in  the  value  of
     the home shell variable.  When followed by a name consisting
     of letters, digits and `-' characters the shell searches for
     a  user with that name and substitutes their home directory;
     thus `~ken' might expand to `/usr/ken' and `~ken/chmach'  to
     `/usr/ken/chmach'.   If  the  character `~' is followed by a
     character other than a letter or `/'  or  appears  elsewhere
     than  at the beginning of a word, it is left undisturbed.  A
     command           like            `setenv            MANPATH
     /usr/man:/usr/local/man:~/lib/man'  does  not, therefore, do
     home directory substitution as one might hope.

     It is an error for a glob-pattern containing `*',  `?',  `['
     or  `~',  with or without `^', not to match any files.  How-
     ever, only one pattern in a list of glob-patterns must match
     a  file  (so that, e.g., `rm *.a *.c *.o' would fail only if
     there were no files in the current directory ending in `.a',
     `.c', or `.o'), and if the nonomatch shell variable is set a
     pattern (or list of patterns) which matches nothing is  left
     unchanged rather than causing an error.

     The noglob shell variable can be  set  to  prevent  filename
     substitution,  and  the expand-glob editor command, normally
     bound to `^X-*', can be used to interactively expand indivi-
     dual filename substitutions.

  Directory stack substitution (+)
     The directory stack is a list of directories, numbered  from
     zero,  used  by  the  pushd,  popd and dirs builtin commands
     (q.v.).  dirs can print, store in a file, restore and  clear
     the  directory stack at any time, and the savedirs and dirs-
     file shell variables can be set to store the directory stack
     automatically  on  logout and restore it on login.  The dir-
     stack shell variable can be examined to  see  the  directory
     stack  and  set to put arbitrary directories into the direc-
     tory stack.

     The character `=' followed by one or more digits expands  to
     an  entry  in  the  directory  stack.  The special case `=-'
     expands to the last directory in the stack.  For example,

         > dirs -v
         0       /usr/bin
         1       /usr/spool/uucp
         2       /usr/accts/sys
         > echo =1
         /usr/spool/uucp
         > echo =0/calendar
         /usr/bin/calendar
         > echo =-
         /usr/accts/sys

     The noglob and nonomatch shell variables and the expand-glob
     editor  command apply to directory stack as well as filename
     substitutions.

  Other substitutions (+)
     There are several more transformations involving  filenames,
     not  strictly  related  to  the above but mentioned here for
     completeness.  Any filename may be expanded to a  full  path
     when the symlinks variable (q.v.) is set to `expand'.  Quot-
     ing prevents this expansion, and the  normalize-path  editor
     command  does  it  on  demand.  The normalize-command editor
     command expands commands in PATH into full paths on  demand.
     Finally,  cd  and  pushd  interpret  `-'  as the old working
     directory (equivalent to the shell variable owd).   This  is
     not a substitution at all, but an abbreviation recognized by
     only those commands.  Nonetheless, it too can  be  prevented
     by quoting.

  Commands
     The next three sections describe how the shell executes com-
     mands and deals with their input and output.

  Simple commands, pipelines and sequences
     A simple command is a sequence of words, the first of  which
     specifies  the  command  to be executed.  A series of simple
     commands joined by `|' characters  forms  a  pipeline.   The
     output  of  each  command  in a pipeline is connected to the
     input of the next.

     Simple commands and pipelines may be joined  into  sequences
     with  `;',  and will be executed sequentially.  Commands and
     pipelines can also be joined into  sequences  with  `||'  or
     `&&',  indicating,  as in the C language, that the second is
     to be executed only if the first fails or  succeeds  respec-
     tively.

     A simple command, pipeline or  sequence  may  be  placed  in
     parentheses,  `()',  to  form a simple command, which may in
     turn be a component of a pipeline or sequence.   A  command,
     pipeline  or sequence can be executed without waiting for it
     to terminate by following it with an `&'.

  Builtin and non-builtin command execution
     Builtin commands are executed within the shell.  If any com-
     ponent  of  a pipeline except the last is a builtin command,
     the pipeline is executed in a subshell.

     Parenthesized commands are always executed in a subshell.

         (cd; pwd); pwd

     thus prints the home directory, leaving you where  you  were
     (printing this after the home directory), while

         cd; pwd

     leaves you in the home  directory.   Parenthesized  commands
     are most often used to prevent cd from affecting the current
     shell.

     When a command to be executed is found not to be  a  builtin
     command  the  shell  attempts  to  execute  the  command via
     execve(2).  Each word in the variable path names a directory
     in  which  the  shell  will  look for the command.  If it is
     given neither a -c nor a -t option,  the  shell  hashes  the
     names in these directories into an internal table so that it
     will try an execve(2) in only a directory where there  is  a
     possibility  that  the  command resides there.  This greatly
     speeds command location when a large number  of  directories
     are  present in the search path.  If this mechanism has been
     turned off (via unhash), if the shell was given a -c  or  -t
     argument or in any case for each directory component of path
     which does not begin with a `/', the shell concatenates  the
     current  working  directory  with  the given command name to
     form a path name of a file which it then  attempts  to  exe-
     cute.

     If the file has execute permissions but is not an executable
     to  the system (i.e., it is neither an executable binary nor
     a script that specifies its interpreter), then it is assumed
     to  be  a  file containing shell commands and a new shell is
     spawned to read it.  The shell special alias may be  set  to
     specify an interpreter other than the shell itself.

     On systems which do not understand the  `#!'  script  inter-
     preter  convention  the shell may be compiled to emulate it;
     see the version shell variable.  If so, the shell checks the
     first line of the file to see if it is of the form `#!inter-
     preter arg ...'.  If it is,  the  shell  starts  interpreter
     with  the  given  args  and feeds the file to it on standard
     input.

  Input/output
     The standard input and standard output of a command  may  be
     redirected with the following syntax:

     < name  Open file name (which is first variable, command and
             filename expanded) as the standard input.
     << word Read the shell input up to a line which is identical
             to   word.   word  is  not  subjected  to  variable,
             filename or command  substitution,  and  each  input
             line  is  compared  to word before any substitutions
             are done on this input line.  Unless a quoting  `\',
             `"',  `' or ``' appears in word variable and command
             substitution is performed on the intervening  lines,
             allowing  `\'  to  quote `$', `\' and ``'.  Commands
             which are substituted have  all  blanks,  tabs,  and
             newlines  preserved,  except  for  the final newline
             which is dropped.  The resultant text is  placed  in
             an  anonymous  temporary  file which is given to the
             command as standard input.
     > name
     >! name
     >& name
     >&! name
             The file name is used as standard  output.   If  the
             file  does not exist then it is created; if the file
             exists, it is truncated, its previous contents being
             lost.

             If the shell variable noclobber  is  set,  then  the
             file  must  not exist or be a character special file
             (e.g.,  a  terminal  or  `/dev/null')  or  an  error
             results.   This helps prevent accidental destruction
             of files.  In this case the `!' forms can be used to
             suppress this check.

             The forms involving `&' route the diagnostic  output
             into the specified file as well as the standard out-
             put.  name is expanded in the same way as `<'  input
             filenames are.
     >> name
     >&gt;& name
     >>! name
     >&gt;&! name
             Like `>', but appends output to the end of name.  If
             the  shell  variable noclobber is set, then it is an
             error for the file not to exist, unless one  of  the
             `!' forms is given.

     A command receives the environment in which  the  shell  was
     invoked  as  modified by the input-output parameters and the
     presence of the command in a pipeline.   Thus,  unlike  some
     previous  shells, commands run from a file of shell commands
     have no access to the  text  of  the  commands  by  default;
     rather  they  receive  the  original  standard  input of the
     shell.  The `<<' mechanism should be used to present  inline
     data.   This  permits  shell  command scripts to function as
     components of pipelines and allows the shell to  block  read
     its  input.  Note that the default standard input for a com-
     mand run detached is not the empty file /dev/null,  but  the
     original standard input of the shell.  If this is a terminal
     and if the process attempts to read from the terminal,  then
     the  process  will  block and the user will be notified (see
     Jobs).

     Diagnostic output may be directed through a  pipe  with  the
     standard  output.  Simply use the form `|&' rather than just
     `|'.

     The  shell  cannot  presently  redirect  diagnostic   output
     without  also  redirecting  standard output, but `(command >
     output-file) >& error-file'  is  often  an  acceptable  wor-
     karound.  Either output-file or error-file may be `/dev/tty'
     to send output to the terminal.

  Features
     Having described how the shell accepts, parses and  executes
     command  lines,  we  now  turn  to  a  variety of its useful
     features.

  Control flow
     The shell contains a number of commands which can be used to
     regulate  the  flow  of  control  in  command  files  (shell
     scripts) and (in limited  but  useful  ways)  from  terminal
     input.   These  commands all operate by forcing the shell to
     reread or skip in its input and, due to the  implementation,
     restrict the placement of some of the commands.

     The foreach, switch, and while statements, as  well  as  the
     if-then-else  form  of  the  if  statement, require that the
     major keywords appear in a single simple command on an input
     line as shown below.

     If the shell's input is not seekable, the shell  buffers  up
     input  whenever  a  loop is being read and performs seeks in
     this internal buffer to accomplish the rereading implied  by
     the  loop.   (To the extent that this allows, backward gotos
     will succeed on non-seekable inputs.)

  Expressions
     The if, while and exit builtin commands use expressions with
     a  common  syntax.   The  expressions can include any of the
     operators described in the next three sections.   Note  that
     the @ builtin command (q.v.) has its own separate syntax.

  Logical, arithmetical and comparison operators
     These operators are similar to those of C and have the  same
     precedence.  They include

         ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
         <  > <<  >>  +  -  *  /  %  !  ~  (  )

     Here the precedence increases to the right, `=='  `!='  `=~'
     and `!~', `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-',
     `*' `/' and `%' being, in groups, at the  same  level.   The
     `==' `!=' `=~' and `!~' operators compare their arguments as
     strings; all others operate on numbers.  The operators  `=~'
     and  `!~'  are like `!=' and `==' except that the right hand
     side is a glob-pattern (see Filename  substitution)  against
     which  the  left  hand operand is matched.  This reduces the
     need for use of the switch builtin command in shell  scripts
     when all that is really needed is pattern matching.

     Strings which begin with `0' are considered  octal  numbers.
     Null  or  missing arguments are considered `0'.  The results
     of all expressions  are  strings,  which  represent  decimal
     numbers.   It is important to note that no two components of
     an expression can appear in the same word; except when adja-
     cent  to  components  of expressions which are syntactically
     significant to the parser (`&' `|' `<'  `>'  `('  `)')  they
     should be surrounded by spaces.

  Command exit status
     Commands can be  executed  in  expressions  and  their  exit
     status   returned   by  enclosing  them  in  braces  (`{}').
     Remember that the braces should be separated from the  words
     of  the  command  by  spaces.   Command  executions succeed,
     returning true, i.e., `1', if the command exits with  status
     0, otherwise they fail, returning false, i.e., `0'.  If more
     detailed status information is  required  then  the  command
     should  be  executed outside of an expression and the status
     shell variable examined.

  File inquiry operators
     Some of these operators perform true/false  tests  on  files
     and  related  objects.  They are of the form -op file, where
     op is one of

         r   Read access
         w   Write access
         x   Execute access
         X   Executable in the path or shell builtin,  e.g.,  `-X
             ls'  and  `-X  ls-F'  are  generally  true,  but `-X
             /bin/ls' is not (+)
         e   Existence
         o   Ownership
         z   Zero size
         s   Non-zero size (+)
         f   Plain file
         d   Directory
         l   Symbolic link (+) *
         b   Block special file (+)
         c   Character special file (+)
         p   Named pipe (fifo) (+) *
         S   Socket special file (+) *
         u   Set-user-ID bit is set (+)
         g   Set-group-ID bit is set (+)
         k   Sticky bit is set (+)
         t   file (which  must  be  a  digit)  is  an  open  file
             descriptor for a terminal device (+)
         R   Has been migrated (convex only) (+)
         L   Applies subsequent operators in a  multiple-operator
             test  to  a symbolic link rather than to the file to
             which the link points (+) *

     file is command and filename expanded and then tested to see
     if  it  has the specified relationship to the real user.  If
     file does not exist or is inaccessible or, for the operators
     indicated  by `*', if the specified file type does not exist
     on the current system,  then  all  enquiries  return  false,
     i.e., `0'.

     These operators may be combined for conciseness: `-xy  file'
     is  equivalent  to  `-x  file && -y file'.  (+) For example,
     `-fx' is true (returns `1') for plain executable files,  but
     not for directories.

     L may be used in a multiple-operator test  to  apply  subse-
     quent  operators  to a symbolic link rather than to the file
     to which the link points.  For example, `-lLo' is  true  for
     links  owned by the invoking user.  Lr, Lw and Lx are always
     true for links and false for non-links.  L has  a  different
     meaning  when it is the last operator in a multiple-operator
     test; see below.

     It is possible but not useful, and sometimes misleading,  to
     combine operators which expect file to be a file with opera-
     tors which do not, (e.g., X and  t).   Following  L  with  a
     non-file operator can lead to particularly strange results.

     Other operators return other information, i.e., not just `0'
     or  `1'.  (+) They have the same format as before; op may be
     one of

         A       Last file access time, as the number of  seconds
                 since the epoch
         A:      Like A, but in timestamp format, e.g., `Fri  May
                 14 16:36:10 1993'
         M       Last file modification time
         M:      Like M, but in timestamp format
         C       Last inode modification time
         C:      Like C, but in timestamp format
         D       Device number
         I       Inode number
         F       Composite   file   identifier,   in   the   form
                 device:inode

         L       The name of the file pointed to  by  a  symbolic
                 link
         N       Number of (hard) links
         P       Permissions, in octal, without leading zero
         P:      Like P, with leading zero
         Pmode   Equivalent to `-P  file  &  mode',  e.g.,  `-P22
                 file'  returns `22' if file is writable by group
                 and other, `20' if by group only, and `0' if  by
                 neither
         Pmode:  Like Pmode:, with leading zero
         U       Numeric userid
         U:      Username, or the numeric userid if the  username
                 is unknown
         G       Numeric groupid
         G:      Groupname, or the numeric groupid if the  group-
                 name is unknown
         Z       Size, in bytes

     Only one of  these  operators  may  appear  in  a  multiple-
     operator  test,  and it must be the last.  Note that L has a
     different  meaning  at  the  end  of  and  elsewhere  in   a
     multiple-operator test.  Because `0' is a valid return value
     for many of these operators, they do  not  return  `0'  when
     they fail: most return `-1', and F returns `:'.

     If the shell is compiled with POSIX defined (see the version
     shell  variable),  the  result of a file inquiry is based on
     the permission bits of the file and not on the result of the
     access(2)  system  call.   For  example, if one tests a file
     with -w whose permissions would ordinarily allow writing but
     which  is  on a file system mounted read-only, the test will
     succeed in a POSIX shell but fail in a non-POSIX shell.

     File inquiry  operators  can  also  be  evaluated  with  the
     filetest builtin command (q.v.) (+).

  Jobs
     The shell associates a job with each pipeline.  It  keeps  a
     table  of  current  jobs,  printed  by the jobs command, and
     assigns them small integer numbers.  When a job  is  started
     asynchronously with `&', the shell prints a line which looks
     like

         [1] 1234

     indicating that the job which was started asynchronously was
     job  number 1 and had one (top-level) process, whose process
     id was 1234.

     If you are running a job and wish to do something  else  you
     may  hit  the suspend key (usually `^Z'), which sends a STOP
     signal to the current job.  The  shell  will  then  normally
     indicate that the job has been `Suspended' and print another
     prompt.  If the listjobs shell variable  is  set,  all  jobs
     will  be  listed like the jobs builtin command; if it is set
     to `long' the listing will be in  long  format,  like  `jobs
     -l'.   You  can  then  manipulate the state of the suspended
     job.  You can put it in the ``background'' with the bg  com-
     mand or run some other commands and eventually bring the job
     back into the ``foreground'' with fg.  (See  also  the  run-
     fg-editor  editor command.)  A `^Z' takes effect immediately
     and is like an interrupt in that pending output  and  unread
     input are discarded when it is typed.  The wait builtin com-
     mand causes the shell to wait for  all  background  jobs  to
     complete.

     The `^]' key sends a delayed suspend signal, which does  not
     generate  a  STOP signal until a program attempts to read(2)
     it, to the current job.  This can usefully  be  typed  ahead
     when  you  have  prepared  some commands for a job which you
     wish to stop after it has read them.  The `^Y' key  performs
     this  function  in  csh(1); in tcsh, `^Y' is an editing com-
     mand.  (+)

     A job being run in the background stops if it tries to  read
     from  the terminal.  Background jobs are normally allowed to
     produce output, but this can be disabled by giving the  com-
     mand  `stty tostop'.  If you set this tty option, then back-
     ground jobs will stop when they try to produce  output  like
     they do when they try to read input.

     There are several ways to refer to jobs in the  shell.   The
     character  `%'  introduces a job name.  If you wish to refer
     to job number 1, you can name it as `%1'.  Just naming a job
     brings  it to the foreground; thus `%1' is a synonym for `fg
     %1', bringing job 1 back into  the  foreground.   Similarly,
     saying `%1 &' resumes job 1 in the background, just like `bg
     %1'.  A job can also be named by an  unambiguous  prefix  of
     the  string  typed in to start it: `%ex' would normally res-
     tart a suspended ex(1) job, if there were only one suspended
     job  whose name began with the string `ex'.  It is also pos-
     sible to say `%?string' to specify a job whose text contains
     string, if there is only one such job.

     The shell maintains a notion of  the  current  and  previous
     jobs.   In  output  pertaining  to  jobs, the current job is
     marked with a `+' and the previous  job  with  a  `-'.   The
     abbreviations  `%+', `%', and (by analogy with the syntax of
     the history mechanism) `%%' all refer to  the  current  job,
     and `%-' refers to the previous job.

     The job control mechanism requires that the  stty(1)  option
     `new'  be  set  on  some  systems.  It is an artifact from a
     `new'  implementation  of  the  tty  driver   which   allows
     generation of interrupt characters from the keyboard to tell
     jobs to stop.  See stty(1) and the setty builtin command for
     details on setting options in the new tty driver.

  Status reporting
     The shell learns  immediately  whenever  a  process  changes
     state.   It  normally  informs  you  whenever  a job becomes
     blocked so that no further progress is  possible,  but  only
     right  before  it  prints a prompt.  This is done so that it
     does not otherwise disturb your work.  If, however, you  set
     the shell variable notify, the shell will notify you immedi-
     ately of changes of status in  background  jobs.   There  is
     also  a shell command notify which marks a single process so
     that its status changes will be  immediately  reported.   By
     default   notify  marks  the  current  process;  simply  say
     `notify' after starting a background job to mark it.

     When you try to leave the shell while jobs are stopped,  you
     will be warned that `You have stopped jobs.' You may use the
     jobs command to see what  they  are.   If  you  do  this  or
     immediately try to exit again, the shell will not warn you a
     second time, and the suspended jobs will be terminated.

  Automatic, periodic and timed events (+)
     There are various  ways  to  run  commands  and  take  other
     actions automatically at various times in the ``life cycle''
     of the shell.  They are summarized here,  and  described  in
     detail under the appropriate Builtin commands, Special shell
     variables and Special aliases.

     The sched builtin command puts commands in a scheduled-event
     list, to be executed by the shell at a given time.

     The beepcmd, cwdcmd, periodic, precmd, and  postcmd  Special
     aliases  can  be set, respectively, to execute commands when
     the shell wants to ring the bell, when the working directory
     changes,  every  tperiod minutes, before each prompt, before
     each command gets executed, after  each  command  gets  exe-
     cuted,  and  when  a  job  is started or is brought into the
     foreground.

     The autologout shell variable can be set to log out or  lock
     the shell after a given number of minutes of inactivity.

     The mail shell variable can be set to  check  for  new  mail
     periodically.

     The printexitvalue shell variable can be set  to  print  the
     exit  status of commands which exit with a status other than
     zero.


     The rmstar shell variable can be set to ask the  user,  when
     `rm *' is typed, if that is really what was meant.

     The time shell variable can be set to execute the time buil-
     tin  command  after the completion of any process that takes
     more than a given number of CPU seconds.

     The watch and who shell variables can be set to report  when
     selected  users  log  in or out, and the log builtin command
     reports on those users at any time.

  Native Language System support (+)
     The shell is eight bit clean (if so compiled; see  the  ver-
     sion  shell variable) and thus supports character sets need-
     ing this  capability.   NLS  support  differs  depending  on
     whether  or  not  the shell was compiled to use the system's
     NLS (again, see version).  In either case,  7-bit  ASCII  is
     the  default for character classification (e.g., which char-
     acters are printable) and sorting, and changing the LANG  or
     LC_CTYPE  environment  variables causes a check for possible
     changes in these respects.

     When using the system's NLS, the setlocale(3C)  function  is
     called to determine appropriate character classification and
     sorting.  This function  typically  examines  the  LANG  and
     LC_CTYPE environment variables; refer to the system documen-
     tation for further details.  When  not  using  the  system's
     NLS,  the shell simulates it by assuming that the ISO 8859-1
     character set is  used  whenever  either  of  the  LANG  and
     LC_CTYPE  variables  are  set,  regardless  of their values.
     Sorting is not affected for the simulated NLS.

     In addition, with both real and simulated NLS, all printable
     characters  in the range \200-\377, i.e., those that have M-
     char bindings, are  automatically  rebound  to  self-insert-
     command.   The  corresponding  binding  for  the escape-char
     sequence, if any, is left alone.  These characters  are  not
     rebound  if  the NOREBIND environment variable is set.  This
     may be useful for the simulated NLS or a primitive real  NLS
     which  assumes full ISO 8859-1.  Otherwise, all M-char bind-
     ings in the range \240-\377 are effectively undone.   Expli-
     citly  rebinding the relevant keys with bindkey is of course
     still possible.

     Unknown characters (i.e., those that are  neither  printable
     nor  control characters) are printed in the format \nnn.  If
     the tty is not in 8 bit mode, other  8  bit  characters  are
     printed by converting them to ASCII and using standout mode.
     The shell never changes the 7/8 bit  mode  of  the  tty  and
     tracks  user-initiated  changes  of 7/8 bit mode.  NLS users
     (or, for that matter, those who want to use a meta key)  may
     need  to  explicitly  set  the tty in 8 bit mode through the
     appropriate stty(1) command in, e.g., the ~/.login file.

  OS variant support (+)
     A number of new builtin commands  are  provided  to  support
     features in particular operating systems.  All are described
     in detail in the Builtin commands section.

     On systems that support TCF (aix-ibm370, aix-ps2),  getspath
     and setspath get and set the system execution path, getxvers
     and setxvers get and set the experimental version prefix and
     migrate  migrates processes between sites.  The jobs builtin
     prints the site on which each job is executing.

     Under Domain/OS, inlib adds shared libraries to the  current
     environment,  rootnode  changes the rootnode and ver changes
     the systype.

     Under Mach, setpath is equivalent to Mach's setpath(1).

     Under Masscomp/RTU  and  Harris  CX/UX,  universe  sets  the
     universe.

     Under Harris CX/UX, ucb or att  runs  a  command  under  the
     specified universe.

     Under Convex/OS, warp prints or sets the universe.

     The VENDOR, OSTYPE and MACHTYPE environment variables  indi-
     cate  respectively  the vendor, operating system and machine
     type (microprocessor class or machine model) of  the  system
     on which the shell thinks it is running.  These are particu-
     larly useful  when  sharing  one's  home  directory  between
     several types of machines; one can, for example,

         set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

     in one's ~/.login and  put  executables  compiled  for  each
     machine in the appropriate directory.

     The version  shell  variable  indicates  what  options  were
     chosen when the shell was compiled.

     Note also the newgrp builtin,  the  afsuser  and  echo_style
     shell  variables  and  the system-dependent locations of the
     shell's input files (see FILES).

  Signal handling
     Login  shells  ignore  interrupts  when  reading  the   file
     ~/.logout.   The  shell  ignores quit signals unless started
     with -q.  Login shells catch the terminate signal, but  non-
     login  shells  inherit  the  terminate  behavior  from their
     parents.  Other signals have  the  values  which  the  shell
     inherited from its parent.

     In shell scripts, the shell's handling of interrupt and ter-
     minate  signals  can be controlled with onintr, and its han-
     dling of hangups can be controlled with hup and nohup.

     The shell exits on a hangup (see also the logout shell vari-
     able).   By  default,  the  shell's children do too, but the
     shell does not send  them  a  hangup  when  it  exits.   hup
     arranges  for  the shell to send a hangup to a child when it
     exits, and nohup sets a child to ignore hangups.

  Terminal management (+)
     The shell uses three different sets  of  terminal  (``tty'')
     modes:   `edit', used when editing, `quote', used when quot-
     ing literal characters, and `execute', used  when  executing
     commands.   The  shell holds some settings in each mode con-
     stant, so commands which leave the tty in a  confused  state
     do  not  interfere  with  the shell.  The shell also matches
     changes in the speed and padding of the tty.   The  list  of
     tty  modes  that are kept constant can be examined and modi-
     fied with the setty builtin.  Note that although the  editor
     uses  CBREAK  mode (or its equivalent), it takes typed-ahead
     characters anyway.

     The echotc, settc and telltc commands can be used to manipu-
     late and debug terminal capabilities from the command line.

     On systems that support SIGWINCH  or  SIGWINDOW,  the  shell
     adapts  to  window  resizing  automatically  and adjusts the
     environment variables LINES and  COLUMNS  if  set.   If  the
     environment  variable  TERMCAP  contains li# and co# fields,
     the shell adjusts them to reflect the new window size.

REFERENCE
     The next sections of this manual describe all of the  avail-
     able  Builtin  commands,  Special  aliases and Special shell
     variables.

  Builtin commands
     %job    A synonym for the fg builtin command.

     %job &  A synonym for the bg builtin command.

     :       Does nothing, successfully.

     @
     @ name = expr
     @ name[index] = expr
     @ name++|--
     @ name[index]++|--
             The first  form  prints  the  values  of  all  shell
             variables.

             The second form assigns the value of expr  to  name.
             The  third  form  assigns  the  value of expr to the
             index'th  component  of  name;  both  name  and  its
             index'th component must already exist.

             expr may contain the operators `*', `+', etc., as in
             C.   If  expr  contains  `<', `>', `&' or `' then at
             least that part of expr must be placed within  `()'.
             Note  that the syntax of expr has nothing to do with
             that described under Expressions.

             The fourth  and  fifth  forms  increment  (`++')  or
             decrement (`--') name or its index'th component.

             The space between `@' and  name  is  required.   The
             spaces between name and `=' and between `=' and expr
             are optional.  Components of expr must be  separated
             by spaces.

     alias [name [wordlist]]
             Without arguments, prints all aliases.   With  name,
             prints  the alias for name.  With name and wordlist,
             assigns wordlist as the alias of name.  wordlist  is
             command  and  filename substituted.  name may not be
             `alias' or `unalias'.  See also the unalias  builtin
             command.

     alloc   Shows the amount of dynamic memory acquired,  broken
             down  into  used  and free memory.  With an argument
             shows the number of free and  used  blocks  in  each
             size  category.   The categories start at size 8 and
             double at each step.  This command's output may vary
             across  system types, because systems other than the
             VAX may use a different memory allocator.

     bg [%job ...]
             Puts the specified jobs (or, without arguments,  the
             current job) into the background, continuing each if
             it is stopped.  job may be a number, a  string,  `',
             `%', `+' or `-' as described under Jobs.

     bindkey [-l|-d|-e|-v|-u] (+)
     bindkey [-a] [-b] [-k] [-r] [--] key (+)
     bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
             Without options, the first form lists all bound keys
             and  the  editor command to which each is bound, the
             second form lists the editor command to which key is
             bound  and  the  third form binds the editor command
             command to key.  Options include:

             -l  Lists all editor commands and a  short  descrip-
                 tion of each.
             -d  Binds all keys to the standard bindings for  the
                 default editor.
             -e  Binds all keys to the  standard  GNU  Emacs-like
                 bindings.
             -v  Binds all keys to the standard vi(1)-like  bind-
                 ings.
             -a  Lists or changes key-bindings in the alternative
                 key map.  This is the key map used in vi command
                 mode.
             -b  key is interpreted as a control character  writ-
                 ten   ^character  (e.g.,  `^A')  or  C-character
                 (e.g.,  `C-A'),  a  meta  character  written  M-
                 character  (e.g., `M-A'), a function key written
                 F-string (e.g., `F-string'), or an extended pre-
                 fix key written X-character (e.g., `X-A').
             -k  key is interpreted as a symbolic arrow key name,
                 which  may  be  one  of  `down', `up', `left' or
                 `right'.
             -r  Removes key's binding.  Be careful: `bindkey -r'
                 does not bind key to self-insert-command (q.v.),
                 it unbinds key completely.
             -c  command is interpreted as a builtin or  external
                 command instead of an editor command.
             -s  command is taken as a literal string and treated
                 as terminal input when key is typed.  Bound keys
                 in command  are  themselves  reinterpreted,  and
                 this continues for ten levels of interpretation.
             --  Forces a break from option  processing,  so  the
                 next word is taken as key even if it begins with
                 '-'.
             -u (or any invalid option)
                 Prints a usage message.

             key may be a single character or  a  string.   If  a
             command is bound to a string, the first character of
             the string is  bound  to  sequence-lead-in  and  the
             entire string is bound to the command.

             Control characters in key can be literal  (they  can
             be  typed  by preceding them with the editor command
             quoted-insert, normally bound to  `^V')  or  written
             caret-character  style, e.g., `^A'.  Delete is writ-
             ten `^?'  (caret-question mark).   key  and  command
             can  contain  backslashed  escape  sequences (in the
             style of System V echo(1)) as follows:

                 \a      Bell
                 \b      Backspace
                 \e      Escape
                 \f      Form feed
                 \n      Newline
                 \r      Carriage return
                 \t      Horizontal tab
                 \v      Vertical tab
                 \nnn    The ASCII character corresponding to the
                         octal number nnn

             `\' nullifies the special meaning of  the  following
             character, if it has any, notably `\' and `^'.

     break   Causes execution to resume  after  the  end  of  the
             nearest  enclosing  foreach or while.  The remaining
             commands on the current line are  executed.   Multi-
             level  breaks  are thus possible by writing them all
             on one line.

     breaksw Causes a break from a  switch,  resuming  after  the
             endsw.

     builtins (+)
             Prints the names of all builtin commands.

     bye (+) A synonym for the logout builtin command.  Available
             only  if  the shell was so compiled; see the version
             shell variable.

     case label:
             A label in a switch statement as discussed below.

     cd [-p] [-l] [-n|-v] [name]
             If a directory name is given,  changes  the  shell's
             working directory to name.  If not, changes to home.
             If name is `-' it is  interpreted  as  the  previous
             working directory (see Other substitutions).  (+) If
             name is not a subdirectory of the current  directory
             (and  does  not begin with `/', `./' or `../'), each
             component of the variable cdpath is checked  to  see
             if it has a subdirectory name.  Finally, if all else
             fails but name  is  a  shell  variable  whose  value
             begins  with `/', then this is tried to see if it is
             a directory.

             With -p, prints the final directory stack, just like
             dirs.   The -l, -n and -v flags have the same effect
             on cd as on dirs, and they imply -p.  (+)

             See also the implicitcd shell variable.

     chdir   A synonym for the cd builtin command.

(+)
     complete [command  [word/pattern/list[:select]/[[suffix]/]  ...]]
             Without arguments, lists all completions.  With com-
             mand, lists completions for command.   With  command
             and word etc., defines completions.

             command may be a full command name or a glob-pattern
             (see  Filename substitution).  It can begin with `-'
             to indicate that completion should be used only when
             command is ambiguous.

             word specifies which word relative  to  the  current
             word  is to be completed, and may be one of the fol-
             lowing:

                 c   Current-word  completion.   pattern   is   a
                     glob-pattern  which must match the beginning
                     of the current word  on  the  command  line.
                     pattern   is  ignored  when  completing  the
                     current word.
                 C   Like c, but includes pattern when completing
                     the current word.
                 n   Next-word completion.  pattern  is  a  glob-
                     pattern  which  must  match the beginning of
                     the previous word on the command line.
                 N   Like n, but must match the beginning of  the
                     word two before the current word.
                 p   Position-dependent completion.  pattern is a
                     numeric  range, with the same syntax used to
                     index shell variables,  which  must  include
                     the current word.

             list, the list of possible completions, may  be  one
             of the following:

                 a       Aliases
                 b       Bindings (editor commands)
                 c       Commands (builtin or external commands)
                 C       External commands which begin  with  the
                         supplied path prefix
                 d       Directories
                 D       Directories which begin  with  the  sup-
                         plied path prefix
                 e       Environment variables
                 f       Filenames
                 F       Filenames which begin with the  supplied
                         path prefix
                 g       Groupnames
                 j       Jobs
                 l       Limits
                 n       Nothing
                 s       Shell variables
                 S       Signals
                 t       Plain (``text'') files
                 T       Plain (``text'') files which begin  with
                         the supplied path prefix
                 v       Any variables
                 u       Usernames
                 x       Like n, but  prints  select  when  list-
                         choices is used.
                 X       Completions
                 $var    Words from the variable var
                 (...)   Words from the given list
                 `...`   Words from the output of command

             select is an optional glob-pattern.  If given, words
             from  only list that match select are considered and
             the fignore shell variable  is  ignored.   The  last
             three types of completion may not have a select pat-
             tern, and x uses select as  an  explanatory  message
             when the list-choices editor command is used.

             suffix is a single character to  be  appended  to  a
             successful  completion.   If  null,  no character is
             appended.  If omitted (in which case the fourth del-
             imiter  can also be omitted), a slash is appended to
             directories and a space to other words.

             Now for some  examples.   Some  commands  take  only
             directories  as  arguments, so there's no point com-
             pleting plain files.

                 > complete cd 'p/1/d/'

             completes only the first word following `cd' (`p/1')
             with  a  directory.   p-type  completion can also be
             used to narrow down command completion:

                 > co[^D]
                 complete compress
                 > complete -co* 'p/0/(compress)/'
                 > co[^D]
                 > compress

             This completion completes commands (words  in  posi-
             tion  0, `p/0') which begin with `co' (thus matching
             `co*') to `compress' (the only word  in  the  list).
             The leading `-' indicates that this completion is to
             be used with only ambiguous commands.

                 > complete find 'n/-user/u/'

             is an example of n-type completion.  Any  word  fol-
             lowing  `find'  and immediately following `-user' is
             completed from the list of users.

                 > complete cc 'c/-I/d/'

             demonstrates c-type completion.  Any word  following
             `cc'  and  beginning  with  `-I'  is  completed as a
             directory.  `-I' is not taken as part of the  direc-
             tory because we used lowercase c.

             Different lists are useful with different commands.

                 > complete alias 'p/1/a/'
                 > complete man 'p/*/c/'
                 > complete set 'p/1/s/'
                 > complete true 'p/1/x:Truth has no options./'

             These complete words following `alias' with aliases,
             `man' with commands, and `set' with shell variables.
             `true' doesn't have any options, so x  does  nothing
             when  completion  is attempted and prints `Truth has
             no options.' when completion choices are listed.

             Note that the man example, and several  other  exam-
             ples  below,  could  just as well have used 'c/*' or
             'n/*' as 'p/*'.

             Words can be completed from a variable evaluated  at
             completion time,

                 > complete ftp 'p/1/$hostnames/'
                 >     set     hostnames     =      (rtfm.mit.edu
                 tesla.ee.cornell.edu)
                 > ftp [^D]
                 rtfm.mit.edu tesla.ee.cornell.edu
                 > ftp [^C]
                 >     set     hostnames     =      (rtfm.mit.edu
                 tesla.ee.cornell.edu uunet.uu.net)
                 > ftp [^D]
                 rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

             or from a command run at completion time:

                 > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                 > kill -9 [^D]
                 23113 23377 23380 23406 23429 23529 23530 PID

             Note that the complete command does not itself quote
             its  arguments,  so  the  braces,  space  and `$' in
             `{print $1}' must be quoted explicitly.

             One command can have multiple completions:

                 > complete dbx 'p/2/(core)/' 'p/*/c/'

             completes the second argument to `dbx' with the word
             `core'  and all other arguments with commands.  Note
             that the positional completion is  specified  before
             the  next-word  completion.  Because completions are
             evaluated from left to right, if the next-word  com-
             pletion  were  specified first it would always match
             and the positional completion would  never  be  exe-
             cuted.   This  is  a  common mistake when defining a
             completion.

             The select pattern is useful when  a  command  takes
             files  with only particular forms as arguments.  For
             example,

                 > complete cc 'p/*/f:*.[cao]/'

             completes `cc' arguments to  files  ending  in  only
             `.c', `.a', or `.o'.  select can also exclude files,
             using negation of a glob-pattern as described  under
             Filename substitution.  One might use

                 >                  complete                   rm
                 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

             to exclude precious source code  from  `rm'  comple-
             tion.   Of  course,  one  could  still type excluded
             names manually or override the completion  mechanism
             using the complete-word-raw or list-choices-raw edi-
             tor commands (q.v.).

             The `C', `D', `F' and `T' lists are like  `c',  `d',
             `f'  and  `t'  respectively, but they use the select
             argument in a different way: to restrict  completion
             to  files  beginning  with a particular path prefix.
             For example, the Elm mail program  uses  `='  as  an
             abbreviation  for  one's  mail directory.  One might
             use

                 > complete elm c@=@F:$HOME/Mail/@

             to complete `elm  -f  ='  as  if  it  were  `elm  -f
             ~/Mail/'.   Note  that we used `@' instead of `/' to
             avoid confusion with the  select  argument,  and  we
             used  `$HOME'  instead of `~' because home directory
             substitution works at only the beginning of a word.

             suffix is used to  add  a  nonstandard  suffix  (not
             space or `/' for directories) to completed words.

                 > complete finger 'c/*@/$hostnames/' 'p/1/u/@'


             completes arguments to `finger'  from  the  list  of
             users,  appends an `@', and then completes after the
             `@' from the `hostnames' variable.  Note  again  the
             order in which the completions are specified.

             Finally, here's a complex example for inspiration:

                 > complete find \
                 'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                 'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                 'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                 'n/-type/(b c d f l p s)/' \
                 'c/-/(name newer cpio ncpio exec ok user \
                 group fstype type atime ctime depth inum \
                 ls mtime nogroup nouser perm print prune \
                 size xdev)/' \
                 'p/*/d/'

             This completes words  following  `-name',  `-newer',
             `-cpio'  or  `ncpio' (note the pattern which matches
             both) to files, words following `-exec' or `-ok'  to
             commands,  words  following  `user'  and  `group' to
             users and groups respectively  and  words  following
             `-fstype'  or `-type' to members of the given lists.
             It also completes the switches themselves  from  the
             given  list  (note the use of c-type completion) and
             completes anything  not  otherwise  completed  to  a
             directory.  Whew.

             Remember that programmed completions are ignored  if
             the  word  being  completed  is a tilde substitution
             (beginning with `~') or a variable  (beginning  with
             `$').   complete is an experimental feature, and the
             syntax may change in future versions of  the  shell.
             See also the uncomplete builtin command.

     continue
             Continues execution of the nearest  enclosing  while
             or foreach.  The rest of the commands on the current
             line are executed.

     default:
             Labels the default case in a switch  statement.   It
             should come after all case labels.

     dirs [-l] [-n|-v]
     dirs -S|-L [filename] (+)
     dirs -c (+)
             The first form prints the directory stack.  The  top
             of  the stack is at the left and the first directory
             in the stack is the current directory.  With -l, `~'
             or  `~name'  in the output is expanded explicitly to
             home or the pathname of the home directory for  user
             name.   (+) With -n, entries are wrapped before they
             reach the edge of the screen.  (+) With -v,  entries
             are  printed  one  per line, preceded by their stack
             positions.  (+) If more than one  of  -n  or  -v  is
             given, -v takes precedence.  -p is accepted but does
             nothing.

             With -S, the second form saves the  directory  stack
             to  filename  as  a series of cd and pushd commands.
             With  -L,  the  shell  sources  filename,  which  is
             presumably  a  directory  stack file saved by the -S
             option or the savedirs mechanism.  In  either  case,
             dirsfile  is  used  if  filename  is  not  given and
             ~/.cshdirs is used if dirsfile is unset.

             Note that login shells do the  equivalent  of  `dirs
             -L'  on  startup  and, if savedirs is set, `dirs -S'
             before exiting.  Because only ~/.tcshrc is  normally
             sourced before ~/.cshdirs, dirsfile should be set in
             ~/.tcshrc rather than ~/.login.

             The last form clears the directory stack.

     echo [-n] word ...
             Writes each word to  the  shell's  standard  output,
             separated  by  spaces and terminated with a newline.
             The echo_style shell variable may be set to  emulate
             (or  not)  the flags and escape sequences of the BSD
             and/or System V versions of echo; see echo(1).

     echotc [-sv] arg ... (+)
             Exercises  the  terminal  capabilities   (see   ter-
             minfo(4)) in args.  For example, 'echotc home' sends
             the cursor to the home position, 'echotc  cm  3  10'
             sends  it  to column 3 and row 10, and 'echotc ts 0;
             echo "This is a test."; echotc fs' prints "This is a
             test."  in the status line.

             If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs',
             prints  the  value of that capability ("yes" or "no"
             indicating that the terminal does or does  not  have
             that  capability).   One  might use this to make the
             output from a shell script less verbose on slow ter-
             minals,  or  limit  command  output to the number of
             lines on the screen:

                 > set history=`echotc lines`
                 > @ history--

             Termcap strings may contain wildcards which will not
             echo  correctly.   One should use double quotes when
             setting a shell variable to  a  terminal  capability
             string,  as in the following example that places the
             date in the status line:

                 > set tosl="`echotc ts 0`"
                 > set frsl="`echotc fs`"
                 > echo -n "$tosl";date; echo -n "$frsl"

             With -s, nonexistent capabilities return  the  empty
             string  rather than causing an error.  With -v, mes-
             sages are verbose.

     else
     end
     endif
     endsw   See the description of the foreach, if, switch,  and
             while statements below.

     eval arg ...
             Treats the arguments as input to the shell and  exe-
             cutes the resulting command(s) in the context of the
             current shell.  This is usually used to execute com-
             mands generated as the result of command or variable
             substitution, because parsing  occurs  before  these
             substitutions.   See  tset(1B)  for  a sample use of
             eval.

     exec command
             Executes the  specified  command  in  place  of  the
             current shell.

     exit [expr]
             The shell exits either with the value of the  speci-
             fied expr (an expression, as described under Expres-
             sions) or, without  expr,  with  the  value  of  the
             status variable.

     fg [%job ...]
             Brings the specified jobs  (or,  without  arguments,
             the  current  job)  into  the foreground, continuing
             each if it is stopped.   job  may  be  a  number,  a
             string, `', `%', `+' or `-' as described under Jobs.
             See also the run-fg-editor editor command.

     filetest -op file ... (+)
             Applies op (which is  a  file  inquiry  operator  as
             described under File inquiry operators) to each file
             and returns the results as a space-separated list.

     foreach name (wordlist)
     ...
     end     Successively sets the variable name to  each  member
             of  wordlist  and  executes the sequence of commands
             between this command and the  matching  end.   (Both
             foreach  and  end  must  appear  alone  on  separate
             lines.)  The builtin command continue may be used to
             continue  the  loop prematurely and the builtin com-
             mand break to terminate it prematurely.   When  this
             command  is read from the terminal, the loop is read
             once prompting with `foreach? ' (or prompt2)  before
             any  statements  in  the  loop are executed.  If you
             make a mistake typing in a loop at the terminal  you
             can rub it out.

     getspath (+)
             Prints the system execution path.  (TCF only)

     getxvers (+)
             Prints the experimental version prefix.  (TCF only)

     glob wordlist
             Like echo, but no `\'  escapes  are  recognized  and
             words  are  delimited by null characters in the out-
             put.  Useful for programs  which  wish  to  use  the
             shell to filename expand a list of words.

     goto word
             word is filename and command-substituted to yield  a
             string  of  the form `label'.  The shell rewinds its
             input as much as possible, searches for  a  line  of
             the  form  `label:',  possibly preceded by blanks or
             tabs, and continues execution after that line.

     hashstat
             Prints a statistics line  indicating  how  effective
             the  internal  hash  table has been at locating com-
             mands (and avoiding exec's).  An exec  is  attempted
             for  each component of the path where the hash func-
             tion indicates a possible hit, and in each component
             which does not begin with a `/'.

             On machines without vfork(2), prints only the number
             and size of hash buckets.

     history [-hTr] [n]
     history -S|-L|-M [filename] (+)
     history -c (+)
             The first form prints the history event list.  If  n
             is  given  only the n most recent events are printed
             or saved.  With -h,  the  history  list  is  printed
             without leading numbers.  If -T is specified, times-
             tamps are printed also in comment form.   (This  can
             be  used  to produce files suitable for loading with
             'history -L' or 'source -h'.)  With -r, the order of
             printing  is  most  recent  first rather than oldest
             first.

             With -S, the second form saves the history  list  to
             filename.   If  the first word of the savehist shell
             variable is set to a number, at most that many lines
             are saved.  If the second word of savehist is set to
             `merge', the history list is merged with the  exist-
             ing  history  file instead of replacing it (if there
             is one) and sorted by time stamp.   (+)  Merging  is
             intended for an environment like the X Window System
             with several shells in simultaneous use.   Currently
             it  succeeds  only  when  the shells quit nicely one
             after another.

             With  -L,  the  shell  appends  filename,  which  is
             presumably  a history list saved by the -S option or
             the savehist mechanism, to the history list.  -M  is
             like  -L,  but  the  contents of filename are merged
             into the history list and sorted by  timestamp.   In
             either  case,  histfile  is  used if filename is not
             given and ~/.history is used if histfile  is  unset.
             `history -L' is exactly like 'source -h' except that
             it does not require a filename.

             Note that login shells do the equivalent of `history
             -L' on startup and, if savehist is set, `history -S'
             before exiting.  Because only ~/.tcshrc is  normally
             sourced before ~/.history, histfile should be set in
             ~/.tcshrc rather than ~/.login.

             If histlit is set, the first and second forms  print
             and  save  the literal (unexpanded) form of the his-
             tory list.

             The last form clears the history list.

     hup [command] (+)
             With command, runs command such that it will exit on
             a  hangup  signal and arranges for the shell to send
             it a hangup signal when the shell exits.  Note  that
             commands  may  set  their  own  response to hangups,
             overriding hup.  Without  an  argument  (allowed  in
             only  a shell script), causes the shell to exit on a
             hangup for the remainder of the  script.   See  also
             Signal handling and the nohup builtin command.

     if (expr) command
             If expr (an expression, as described  under  Expres-
             sions)  evaluates  true,  then  command is executed.
             Variable substitution on command happens  early,  at
             the  same  time  it  does  for  the  rest  of the if
             command.  command must be a simple command,  not  an
             alias, a pipeline, a command list or a parenthesized
             command   list,   but   it   may   have   arguments.
             Input/output  redirection  occurs  even  if  expr is
             false and command is thus not executed;  this  is  a
             bug.

     if (expr) then
     ...
     else if (expr2) then
     ...
     else
     ...
     endif   If the specified expr is true then the  commands  to
             the  first  else are executed; otherwise if expr2 is
             true then the commands to the second else  are  exe-
             cuted,  etc.  Any number of else-if pairs are possi-
             ble; only one endif is needed.   The  else  part  is
             likewise  optional.   (The words else and endif must
             appear at the beginning of input lines; the if  must
             appear alone on its input line or after an else.)

     inlib shared-library ... (+)
             Adds each shared-library to the current environment.
             There   is  no  way  to  remove  a  shared  library.
             (Domain/OS only)

     jobs [-l]
             Lists the active jobs.  With -l, lists  process  IDs
             in  addition to the normal information.  On TCF sys-
             tems, prints the site on which each job  is  execut-
             ing.

     kill [-signal] %job|pid ...
     kill -l The first and second forms send the specified signal
             (or,  if none is given, the TERM (terminate) signal)
             to the specified jobs or processes.  job  may  be  a
             number,  a  string, `', `%', `+' or `-' as described
             under Jobs.  Signals are either given by  number  or
             by name (as given in /usr/include/signal.h, stripped
             of the prefix `SIG').  There is no default job; say-
             ing  just  `kill'  does  not  send  a  signal to the
             current job.  If the signal being sent is TERM (ter-
             minate)  or HUP (hangup), then the job or process is
             sent a CONT (continue) signal as  well.   The  third
             form lists the signal names.

     limit [-h] [resource [maximum-use]]
             Limits the consumption by the  current  process  and
             each  process  it creates to not individually exceed
             maximum-use  on  the  specified  resource.   If   no
             maximum-use  is  given,  then  the  current limit is
             printed; if no resource is given, then  all  limita-
             tions  are given.  If the -h flag is given, the hard
             limits are used instead of the current limits.   The
             hard  limits  impose  a ceiling on the values of the
             current limits.  Only the super-user may  raise  the
             hard  limits,  but  a  user  may  lower or raise the
             current limits within the legal range.

             Controllable resources currently  include  (if  sup-
             ported by the OS):

             cputime
                  the maximum number of cpu-seconds to be used by
                  each process

             filesize
                  the largest single file which can be created

             datasize
                  the maximum growth of the data+stack region via
                  sbrk(2) beyond the end of the program text

             stacksize
                  the maximum size of the  automatically-extended
                  stack region

             coredumpsize
                  the size of the largest core dump that will  be
                  created

             memoryuse
                  the maximum amount of physical memory a process
                  may have allocated to it at a given time

             descriptors or openfiles
                  the maximum number of open files for this  pro-
                  cess

             concurrency
                  the maximum number of threads for this process

             memorylocked
                  the maximum size which a process may lock  into
                  memory using mlock(2)

             maxproc
                  the maximum number  of  simultaneous  processes
                  for this user id

             sbsize
                  the maximum size of  socket  buffer  usage  for
                  this user

             maximum-use may be given as  a  (floating  point  or
             integer) number followed by a scale factor.  For all
             limits other than cputime the default scale  is  `k'
             or  `kilobytes'  (1024 bytes); a scale factor of `m'
             or `megabytes' may also be used.   For  cputime  the
             default  scaling is `seconds', while `m' for minutes
             or `h' for hours, or a time of the form `mm:ss' giv-
             ing minutes and seconds may be used.

             For both resource names and scale factors, unambigu-
             ous prefixes of the names suffice.

     log (+) Prints the watch shell variable and reports on  each
             user indicated in watch who is logged in, regardless
             of when they last logged in.  See also watchlog.

     login   Terminates a  login  shell,  replacing  it  with  an
             instance  of /bin/login. This is one way to log off,
             included for compatibility with sh(1).

     logout  Terminates a  login  shell.   Especially  useful  if
             ignoreeof is set.

     ls-F [-switch ...] [file ...] (+)
             Lists files like `ls -F', but much faster.  It iden-
             tifies each type of special file in the listing with
             a special character:

             /   Directory
             *   Executable
             #   Block device
             %   Character device
             |   Named pipe (systems with named pipes only)
             =   Socket (systems with sockets only)
             @   Symbolic link (systems with symbolic links only)
             +   Hidden directory (AIX only) or context dependent
                 (HP/UX only)
             :   Network special (HP/UX only)

             If the listlinks shell  variable  is  set,  symbolic
             links are identified in more detail (on only systems
             that have them, of course):

             @   Symbolic link to a non-directory
             >   Symbolic link to a directory
             &   Symbolic link to nowhere

             listlinks also slows down ls-F and causes partitions
             holding  files  pointed  to  by symbolic links to be
             mounted.


             If the listflags shell variable is set to  `x',  `a'
             or  `A',  or  any  combination thereof (e.g., `xA'),
             they are used as flags to ls-F, making it  act  like
             `ls -xF', `ls -Fa', `ls -FA' or a combination (e.g.,
             `ls -FxA').  On machines where `ls -C'  is  not  the
             default,  ls-F  acts like `ls -CF', unless listflags
             contains an `x', in which  case  it  acts  like  `ls
             -xF'.   ls-F  passes its arguments to ls(1) if it is
             given any switches, so  `alias  ls  ls-F'  generally
             does the right thing.

             The ls-F builtin  can  list  files  using  different
             colors  depending on the filetype or extension.  See
             the color tcsh variable and the  LS_COLORS  environ-
             ment variable.

     migrate [-site] pid|%jobid ... (+)
     migrate -site (+)
             The first form migrates the process or  job  to  the
             site specified or the default site determined by the
             system path.   The  second  form  is  equivalent  to
             `migrate  -site $$': it migrates the current process
             to the specified site.  Migrating the  shell  itself
             can  cause  unexpected  behavior,  because the shell
             does not like to lose its tty.  (TCF only)

     newgrp [-] group (+)
             Equivalent to `exec newgrp'; see newgrp(1).   Avail-
             able only if the shell was so compiled; see the ver-
             sion shell variable.

     nice [+number] [command]
             Sets  the  scheduling  priority  for  the  shell  to
             number,  or,  without  number,  to 4.  With command,
             runs  command  at  the  appropriate  priority.   The
             greater  the  number, the less cpu the process gets.
             The super-user  may  specify  negative  priority  by
             using  `nice  -number  ...'.  Command is always exe-
             cuted in a sub-shell, and the restrictions placed on
             commands in simple if statements apply.

     nohup [command]
             With command, runs command such that it will  ignore
             hangup  signals.   Note  that commands may set their
             own response to hangups, overriding nohup.   Without
             an argument (allowed in only a shell script), causes
             the shell to ignore hangups for the remainder of the
             script.   See also Signal handling and the hup buil-
             tin command.

     notify [%job ...]
             Causes the shell to notify the  user  asynchronously
             when  the  status  of any of the specified jobs (or,
             without %job, the current job) changes,  instead  of
             waiting  until the next prompt as is usual.  job may
             be a number, a  string,  `',  `%',  `+'  or  `-'  as
             described  under  Jobs.   See  also the notify shell
             variable.

     onintr [-|label]
             Controls the action  of  the  shell  on  interrupts.
             Without  arguments,  restores  the default action of
             the shell on interrupts, which is to terminate shell
             scripts  or  to return to the terminal command input
             level.   With  `-',  causes  all  interrupts  to  be
             ignored.   With label, causes the shell to execute a
             `goto label' when an  interrupt  is  received  or  a
             child process terminates because it was interrupted.

             onintr is ignored if the shell is  running  detached
             and  in  system  startup  files  (see  FILES), where
             interrupts are disabled anyway.

     popd [-p] [-l] [-n|-v] [+n]
             Without arguments,  pops  the  directory  stack  and
             returns  to  the  new  top directory.  With a number
             `+n', discards the n'th entry in the stack.

             Finally, all forms of popd print the final directory
             stack,  just like dirs.  The pushdsilent shell vari-
             able can be set to prevent this and the -p flag  can
             be given to override pushdsilent.  The -l, -n and -v
             flags have the same effect on popd as on dirs.  (+)

     printenv [name] (+)
             Prints the names and values of all environment vari-
             ables  or,  with  name, the value of the environment
             variable name.

     pushd [-p] [-l] [-n|-v] [name|+n]
             Without arguments, exchanges the top two elements of
             the  directory  stack.  If pushdtohome is set, pushd
             without arguments does `pushd ~', like cd.  (+) With
             name,  pushes the current working directory onto the
             directory stack and changes to name.  If name is `-'
             it  is interpreted as the previous working directory
             (see Filename substitution).  (+) If dunique is set,
             pushd  removes  any instances of name from the stack
             before pushing it onto the stack.  (+) With a number
             `+n', rotates the nth element of the directory stack
             around to be the top element and changes to it.   If
             dextract  is  set,  however, `pushd +n' extracts the
             nth directory, pushes it onto the top of  the  stack
             and changes to it.  (+)
             Finally, all forms of pushd print the  final  direc-
             tory  stack,  just like dirs.  The pushdsilent shell
             variable can be set to prevent this and the -p  flag
             can  be  given  to override pushdsilent.  The -l, -n
             and -v flags have the same effect  on  pushd  as  on
             dirs.  (+)

     rehash  Causes the internal hash table of  the  contents  of
             the  directories  in  the path variable to be recom-
             puted.  This is needed if new commands are added  to
             directories  in  path while you are logged in.  This
             should be necessary only if you add commands to  one
             of  your own directories, or if a systems programmer
             changes the contents of one  of  the  system  direc-
             tories.   Also flushes the cache of home directories
             built by tilde expansion.

     repeat count command
             The specified command, which is subject to the  same
             restrictions  as  the  command  in  the  one line if
             statement  above,  is  executed  count  times.   I/O
             redirections occur exactly once, even if count is 0.

     rootnode //nodename (+)
             Changes the rootnode to //nodename, so that `/' will
             be interpreted as `//nodename'.  (Domain/OS only)

     sched (+)
     sched [+]hh:mm command (+)
     sched -n (+)
             The first form prints the scheduled-event list.  The
             sched shell variable may be set to define the format
             in which the scheduled-event list is  printed.   The
             second  form  adds  command  to  the scheduled-event
             list.  For example,

                 > sched 11:00 echo It\'s eleven o\'clock.

             causes the shell to echo `It's eleven  o'clock.'  at
             11 AM.  The time may be in 12-hour AM/PM format

                 > sched 5pm set prompt='[%h] It\'s after  5;  go
                 home: >'

             or may be relative to the current time:

                 > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

             A relative time specification may not use AM/PM for-
             mat.   The  third form removes item n from the event
             list:

                 > sched
                      1  Wed Apr  4  15:42   /usr/lib/uucp/uucico
                 -r1 -sother
                      2  Wed Apr  4 17:00  set  prompt=[%h]  It's
                 after 5; go home: >
                 > sched -2
                 > sched
                      1  Wed Apr  4  15:42   /usr/lib/uucp/uucico
                 -r1 -sother

             A command in the scheduled-event  list  is  executed
             just  before  the  first prompt is printed after the
             time when the command is scheduled.  It is  possible
             to  miss  the  exact  time when the command is to be
             run, but an overdue command will execute at the next
             prompt.   A  command which comes due while the shell
             is waiting for user input is  executed  immediately.
             However, normal operation of an already-running com-
             mand will not be interrupted so  that  a  scheduled-
             event list element may be run.

             This mechanism is similar to, but not the  same  as,
             the  at(1)  command on some Unix systems.  Its major
             disadvantage is that it may not  run  a  command  at
             exactly  the specified time.  Its major advantage is
             that because sched runs directly from the shell,  it
             has  access to shell variables and other structures.
             This provides a mechanism for changing one's working
             environment based on the time of day.

     set
     set name ...
     set name=word ...
     set [-r] [-f|-l] name=(wordlist) ... (+)
     set name[index]=word ...
     set -r (+)
     set -r name ... (+)
     set -r name=word ... (+)
             The first form of the command prints  the  value  of
             all  shell  variables.  Variables which contain more
             than a single word print  as  a  parenthesized  word
             list.  The second form sets name to the null string.
             The third form sets name to the  single  word.   The
             fourth  form  sets  name  to  the  list  of words in
             wordlist.  In all cases the  value  is  command  and
             filename expanded.  If -r is specified, the value is
             set read-only.  If -f or -l are specified, set  only
             unique  words  keeping  their order.  -f prefers the
             first occurrence of a word, and -l  the  last.   The
             fifth  form  sets  the index'th component of name to
             word; this component must already exist.  The  sixth
             form  lists  only  the  names of all shell variables
             that are read-only.  The  seventh  form  makes  name
             read-only,  whether  or  not  it  has  a value.  The
             second form sets  name  to  the  null  string.   The
             eighth  form is the same as the third form, but make
             name read-only at the same time.

             These arguments can be repeated to set  and/or  make
             read-only  multiple  variables  in a single set com-
             mand.  Note, however, that variable  expansion  hap-
             pens  for  all  arguments before any setting occurs.
             Note also that `=' can be adjacent to both name  and
             word  or separated from both by whitespace, but can-
             not be adjacent to only one or the other.  See  also
             the unset builtin command.

     setenv [name [value]]
             Without arguments, prints the names  and  values  of
             all  environment  variables.   Given  name, sets the
             environment  variable  name  to  value  or,  without
             value, to the null string.

     setpath path (+)
             Equivalent to setpath(1).  (Mach only)

     setspath LOCAL|site|cpu ... (+)
             Sets the system execution path.  (TCF only)

     settc cap value (+)
             Tells the shell to believe that the  terminal  capa-
             bility cap (as defined in terminfo(4)) has the value
             value.  No sanity checking is done.  Concept  termi-
             nal  users  may  have to `settc xn no' to get proper
             wrapping at the rightmost column.

     setty [-d|-q|-x] [-a] [[+|-]mode] (+)
             Controls which tty modes (see  Terminal  management)
             the  shell  does  not allow to change.  -d, -q or -x
             tells setty to act on the `edit', `quote'  or  `exe-
             cute'  set of tty modes respectively; without -d, -q
             or -x, `execute' is used.

             Without other arguments, setty lists  the  modes  in
             the  chosen  set which are fixed on (`+mode') or off
             (`-mode').   The  available  modes,  and  thus   the
             display, vary from system to system.  With -a, lists
             all tty modes in the chosen set whether or not  they
             are fixed.  With +mode, -mode or mode, fixes mode on
             or off or removes control from mode  in  the  chosen
             set.    For  example,  `setty  +echok  echoe'  fixes
             `echok' mode on and allows commands to turn  `echoe'
             mode  on  or  off,  both when the shell is executing
             commands.

     setxvers [string] (+)
             Set the experimental version prefix  to  string,  or
             removes it if string is omitted.  (TCF only)

     shift [variable]
             Without arguments, discards argv[1] and  shifts  the
             members  of  argv  to  the left.  It is an error for
             argv not to be set or to have less than one word  as
             value.  With variable, performs the same function on
             variable.

     source [-h] name [args ...]
             The shell reads and  executes  commands  from  name.
             The commands are not placed on the history list.  If
             any args are given, they are placed  in  argv.   (+)
             source  commands  may  be nested; if they are nested
             too deeply the shell may run out  of  file  descrip-
             tors.   An error in a source at any level terminates
             all nested source commands.  With -h,  commands  are
             placed  on  the  history  list instead of being exe-
             cuted, much like `history -L'.

     stop %job|pid ...
             Stops the specified jobs or processes which are exe-
             cuting  in  the  background.  job may be a number, a
             string, `', `%', `+' or `-' as described under Jobs.
             There is no default job; saying just `stop' does not
             stop the current job.

     suspend Causes the shell to stop in its tracks, much  as  if
             it  had  been  sent  a stop signal with ^Z.  This is
             most often used to stop shells started by su(1M).

     switch (string)
     case str1:
         ...
         breaksw
     ...
     default:
         ...
         breaksw
     endsw   Each case label is successively matched, against the
             specified string which is first command and filename
             expanded.  The  file  metacharacters  `*',  `?'  and
             `[...]'   may  be used in the case labels, which are
             variable expanded.  If  none  of  the  labels  match
             before  a  `default' label is found, then the execu-
             tion begins after  the  default  label.   Each  case
             label  and  the  default  label  must  appear at the
             beginning of a line.   The  command  breaksw  causes
             execution  to  continue  after the endsw.  Otherwise
             control may fall through  case  labels  and  default
             labels as in C.  If no label matches and there is no
             default, execution continues after the endsw.

     telltc (+)
             Lists the values of all terminal  capabilities  (see
             terminfo(4)).

     time [command]
             Executes command (which must be  a  simple  command,
             not  an  alias,  a  pipeline,  a  command  list or a
             parenthesized command list) and prints a  time  sum-
             mary  as  described  under  the  time  variable.  If
             necessary, an extra shell is created  to  print  the
             time  statistic when the command completes.  Without
             command, prints a time summary for the current shell
             and its children.

     umask [value]
             Sets the file creation mask to value, which is given
             in  octal.  Common values for the mask are 002, giv-
             ing all access to the group  and  read  and  execute
             access  to  others, and 022, giving read and execute
             access to the  group  and  others.   Without  value,
             prints the current file creation mask.

     unalias pattern
             Removes  all  aliases  whose  names  match  pattern.
             `unalias  *' thus removes all aliases.  It is not an
             error for nothing to be unaliased.

     uncomplete pattern (+)
             Removes all completions whose names  match  pattern.
             `uncomplete  *' thus removes all completions.  It is
             not an error for nothing to be uncompleted.

     unhash  Disables use of the internal  hash  table  to  speed
             location of executed programs.

     universe universe (+)
             Sets the universe to universe.  (Masscomp/RTU only)

     unlimit [-h] [resource]
             Removes  the  limitation  on  resource  or,  if   no
             resource  is  specified,  all  resource limitations.
             With -h, the corresponding hard limits are  removed.
             Only the super-user may do this.

     unset pattern
             Removes all variables  whose  names  match  pattern,
             unless  they  are read-only.  `unset *' thus removes
             all variables unless they are read-only; this  is  a
             bad  idea.   It  is  not  an error for nothing to be
             unset.

     unsetenv pattern
             Removes all environment variables whose names  match
             pattern.   `unsetenv *' thus removes all environment
             variables; this is a bad idea.  It is not  an  error
             for nothing to be unsetenved.

     ver [systype [command]] (+)
             Without arguments, prints  SYSTYPE.   With  systype,
             sets  SYSTYPE to systype.  With systype and command,
             executes command  under  systype.   systype  may  be
             `bsd4.3' or `sys5.3'.  (Domain/OS only)

     wait    The shell waits for all  background  jobs.   If  the
             shell  is interactive, an interrupt will disrupt the
             wait and cause the shell to print the names and  job
             numbers of all outstanding jobs.

     warp universe (+)
             Sets the universe to universe.  (Convex/OS only)

     watchlog (+)
             An  alternate  name  for  the  log  builtin  command
             (q.v.).   Available  only  if  the shell was so com-
             piled; see the version shell variable.

     where command (+)
             Reports all known instances  of  command,  including
             aliases, builtins and executables in path.

     which command (+)
             Displays the command that will be  executed  by  the
             shell after substitutions, path searching, etc.  The
             builtin  command  is  just  like  which(1),  but  it
             correctly  reports  tcsh aliases and builtins and is
             10 to 100 times faster.  See also the  which-command
             editor command.

     while (expr)
     ...
     end     Executes the commands  between  the  while  and  the
             matching end while expr (an expression, as described
             under Expressions) evaluates  non-zero.   while  and
             end  must  appear alone on their input lines.  break
             and continue may be used to  terminate  or  continue
             the  loop  prematurely.  If the input is a terminal,
             the user is prompted the first time through the loop
             as with foreach.

  Special aliases (+)
     If set, each of these aliases executes automatically at  the
     indicated time.  They are all initially undefined.

     beepcmd Runs when the shell wants to ring the terminal bell.

     cwdcmd  Runs after every change of working  directory.   For
             example,  if the user is working on an X window sys-
             tem using xterm(1) and a re-parenting window manager
             that supports title bars such as twm(1) and does

                 > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

             then the shell will change the title of the  running
             xterm(1)  to  be  the name of the host, a colon, and
             the full current working directory.  A  fancier  way
             to do that is

                 >       alias       cwdcmd       'echo        -n
                 "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

             This will put the hostname and working directory  on
             the  title  bar  but  only  the hostname in the icon
             manager menu.

             Note that putting a cd, pushd or popd in cwdcmd  may
             cause  an infinite loop.  It is the author's opinion
             that anyone doing so will get what they deserve.

     jobcmd  Runs before each command gets executed, or when  the
             command  changes state.  This is similar to postcmd,
             but it does not print builtins.

                 > alias jobcmd  'echo -n "^[]2\;\!#^G"'

             then executing vi foo.c will put the command  string
             in the xterm title bar.

     helpcommand
             Invoked by the run-help editor command.  The command
             name  for  which  help  is  sought is passed as sole
             argument.  For example, if one does

                 > alias helpcommand '\!:1 --help'

             then the help display of the command itself will  be
             invoked,  using  the  GNU  help  calling convention.
             Currently there is no easy way to account for  vari-
             ous  calling  conventions  (e.g., the customary Unix
             `-h'), except by using a table of many commands.

     periodic
             Runs every tperiod minutes.  This  provides  a  con-
             venient  means for checking on common but infrequent
             changes such as new mail.  For example, if one does

                 > set tperiod = 30
                 > alias periodic checknews

             then the checknews(1) program runs every 30 minutes.
             If periodic is set but tperiod is unset or set to 0,
             periodic behaves like precmd.

     precmd  Runs just before each prompt is printed.  For  exam-
             ple, if one does

                 > alias precmd date

             then date(1) runs just before the shell prompts  for
             each  command.   There  are no limits on what precmd
             can be set to do, but discretion should be used.

     postcmd Runs before each command gets executed.

                 > alias postcmd  'echo -n "^[]2\;\!#^G"'

             then executing vi foo.c will put the command  string
             in the xterm title bar.

     shell   Specifies the  interpreter  for  executable  scripts
             which do not themselves specify an interpreter.  The
             first word should be a full path name to the desired
             interpreter        (e.g.,        `/bin/csh'       or
             `/usr/local/bin/tcsh').

  Special shell variables
     The variables described in this section have special meaning
     to the shell.

     The  shell  sets  addsuffix,  argv,   autologout,   command,
     echo_style,  edit,  gid,  group,  home,  loginsh, oid, path,
     prompt, prompt2, prompt3, shell,  shlvl,  tcsh,  term,  tty,
     uid,  user  and  version  at  startup;  they  do  not change
     thereafter unless changed by the user.   The  shell  updates
     cwd,  dirstack,  owd  and  status  when  necessary, and sets
     logout on logout.

     The shell synchronizes afsuser, group,  home,  path,  shlvl,
     term  and  user  with  the environment variables of the same
     names:  whenever the environment variable changes the  shell
     changes  the  corresponding  shell variable to match (unless
     the shell variable is read-only) and vice versa.  Note  that
     although  cwd  and PWD have identical meanings, they are not
     synchronized in this manner, and that  the  shell  automati-
     cally interconverts the different formats of path and PATH.

     addsuffix (+)
             If set, filename completion adds `/' to the  end  of
             directories  and  a space to the end of normal files
             when they are matched exactly.  Set by default.

     afsuser (+)
             If set, autologout's autolock feature uses its value
             instead of the local username for kerberos authenti-
             cation.

     ampm (+)
             If set, all times are shown in 12-hour AM/PM format.

     argv    The arguments to the shell.   Positional  parameters
             are  taken  from  argv,  i.e.,  `$1'  is replaced by
             `$argv[1]', etc.  Set by default, but usually  empty
             in interactive shells.

     autocorrect (+)
             If set, the spell-word  editor  command  is  invoked
             automatically before each completion attempt.

     autoexpand (+)
             If set, the expand-history editor command is invoked
             automatically before each completion attempt.

     autolist (+)
             If set, possibilities are listed after an  ambiguous
             completion.   If  set  to `ambiguous', possibilities
             are listed only when no new characters are added  by
             completion.

     autologout (+)
             The first word is the number  of  minutes  of  inac-
             tivity before automatic logout.  The optional second
             word is the number of minutes of  inactivity  before
             automatic  locking.   When  the  shell automatically
             logs out, it prints `auto-logout', sets the variable
             logout  to  `automatic'  and  exits.  When the shell
             automatically locks, the user is required  to  enter
             his  password  to  continue working.  Five incorrect
             attempts result in automatic logout.   Set  to  `60'
             (automatic  logout after 60 minutes, and no locking)
             by default in login and superuser shells, but not if
             the shell thinks it is running under a window system
             (i.e., the DISPLAY environment variable is set), the
             tty  is  a  pseudo-tty (pty) or the shell was not so
             compiled (see the version shell variable).  See also
             the afsuser and logout shell variables.

     backslash_quote (+)
             If set, backslashes (`\') always quote `\', `'', and
             `"'.   This  may  make complex quoting tasks easier,
             but it can cause syntax errors in csh(1) scripts.

     catalog The file name of the message catalog.  If set,  tcsh
             use  `tcsh.${catalog}'  as a message catalog instead
             of default `tcsh'.

     cdpath  A list of directories in which cd should search  for
             subdirectories  if  they aren't found in the current
             directory.

     color   If set, it enables color  display  for  the  builtin
             ls-F  and  it  passes  --color=auto to ls.  Alterna-
             tively, it can be set to only ls-F  or  only  ls  to
             enable  color  to  only  one command.  Setting it to
             nothing is equivalent to setting it to (ls-F ls).

     colorcat
             If set, it enables color  escape  sequence  for  NLS
             message files.  And display colorful NLS messages.

     command (+)
             If set, the command which was passed  to  the  shell
             with the -c flag (q.v.).

     complete (+)
             If set to `enhance', completion 1) ignores case  and
             2)  considers periods, hyphens and underscores (`.',
             `-' and `_') to be word separators and  hyphens  and
             underscores to be equivalent.

     continue (+)
             If set to a list of commands, the  shell  will  con-
             tinue the listed commands, instead of starting a new
             one.

     continue_args (+)
             Same as continue, but the shell will execute:

                 echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

     correct (+)
             If  set  to  `cmd',   commands   are   automatically
             spelling-corrected.   If set to `complete', commands
             are automatically completed.  If set to  `all',  the
             entire command line is corrected.

     cwd     The full pathname of  the  current  directory.   See
             also the dirstack and owd shell variables.

     dextract (+)
             If set, `pushd +n' extracts the nth  directory  from
             the  directory  stack rather than rotating it to the
             top.

     dirsfile (+)
             The default location in which `dirs  -S'  and  `dirs
             -L'  look  for a history file.  If unset, ~/.cshdirs
             is used.  Because only ~/.tcshrc is normally sourced
             before   ~/.cshdirs,   dirsfile  should  be  set  in
             ~/.tcshrc rather than ~/.login.

     dirstack (+)
             An array of all the  directories  on  the  directory
             stack.  `$dirstack[1]' is the current working direc-
             tory, `$dirstack[2]'  the  first  directory  on  the
             stack, etc.  Note that the current working directory
             is `$dirstack[1]' but `=0' in directory  stack  sub-
             stitutions,  etc.   One  can  change the stack arbi-
             trarily by setting dirstack, but the  first  element
             (the  current  working directory) is always correct.
             See also the cwd and owd shell variables.

     dspmbyte (+)
             If set to `euc',  it  enables  display  and  editing
             EUC-kanji(Japanese)  code.   If  set  to  `sjis', it
             enables  display  and  editing   Shift-JIS(Japanese)
             code.   If  set  to  `big5',  it enables display and
             editing Big5(Chinese) code.  If set  to  `utf8',  it
             enables  display and editing Utf8(Unicode) code.  If
             set to the following format, it enables display  and
             editing of original multi-byte code format:

                 > set dspmbyte = 0000....(256 bytes)....0000

             The table requires just 256 bytes.   Each  character
             of  256  characters corresponds (from left to right)
             to the ASCII codes 0x00, 0x01, ... 0xff.  Each char-
             acter is set to number 0,1,2 and 3.  Each number has
             the following meaning:
               0 ... not used for multi-byte characters.
               1 ... used for the  first  byte  of  a  multi-byte
             character.
               2 ... used for the second  byte  of  a  multi-byte
             character.
               3 ... used for both the first byte and second byte
             of a multi-byte character.







               Example:
             If set to `001322', the first character (means  0x00
             of  the ASCII code) and second character (means 0x01
             of ASCII code) are set to `0'.  Then, it is not used
             for multi-byte characters.  The 3rd character (0x02)
             is set to '2', indicating that it is  used  for  the
             first  byte  of  a  multi-byte  character.   The 4th
             character(0x03) is set '3'.  It is used for both the
             first byte and the second byte of a multi-byte char-
             acter.  The 5th and 6th characters  (0x04,0x05)  are
             set  to  '2',  indicating that they are used for the
             second byte of a multi-byte character.

             The GNU  fileutils  version  of  ls  cannot  display
             multi-byte  filenames  without  the -N ( --literal )
             option.   If you are using  this  version,  set  the
             second  word of dspmbyte to "ls".  If not, for exam-
             ple, "ls-F -l" cannot display multi-byte filenames.

               Note:
             This variable can only be used if KANJI and DSPMBYTE
             has been defined at compile time.

     dunique (+)
             If set, pushd removes any instances of name from the
             stack before pushing it onto the stack.

     echo    If set, each command with its  arguments  is  echoed
             just  before  it  is executed.  For non-builtin com-
             mands all expansions occur before echoing.   Builtin
             commands are echoed before command and filename sub-
             stitution, because these substitutions are then done
             selectively.  Set by the -x command line option.

     echo_style (+)
             The style of the echo builtin.  May be set to

             bsd     Don't echo a newline if the  first  argument
                     is `-n'.
             sysv    Recognize backslashed  escape  sequences  in
                     echo strings.
             both    Recognize both the `-n' flag and backslashed
                     escape sequences; the default.
             none    Recognize neither.

             Set by default to the local system default.  The BSD
             and  System  V  options are described in the echo(1)
             man pages on the appropriate systems.

     edit (+)
             If set, the command-line editor  is  used.   Set  by
             default in interactive shells.

     ellipsis (+)
             If set, the `%c'/`%.' and `%C' prompt sequences (see
             the  prompt  shell variable) indicate skipped direc-
             tories  with  an  ellipsis   (`...')    instead   of
             `/<skipped>'.

     fignore (+)
             Lists file name suffixes to be  ignored  by  comple-
             tion.

     filec   In tcsh, completion is always used and this variable
             is  ignored  by  default. If edit is unset, then the
             traditional csh completion is used.  If set in  csh,
             filename completion is used.

     gid (+) The user's real group ID.

     group (+)
             The user's group name.

     histchars
             A string value determining the  characters  used  in
             History substitution (q.v.).  The first character of
             its value is used as the history substitution  char-
             acter,  replacing  the  default  character `!'.  The
             second character of its value replaces the character
             `^' in quick substitutions.

     histdup (+)
             Controls handling of duplicate entries in  the  his-
             tory  list.   If  set  to  `all' only unique history
             events are entered in the history list.  If  set  to
             `prev' and the last history event is the same as the
             current command, then the  current  command  is  not
             entered  in  the history.  If set to `erase' and the
             same event is found in the history  list,  that  old
             event gets erased and the current one gets inserted.
             Note that the `prev' and `all' options renumber his-
             tory events so there are no gaps.

     histfile (+)
             The default location in which `history -S' and `his-
             tory -L' look for a history file.  If unset, ~/.his-
             tory is used.  histfile is useful when  sharing  the
             same  home  directory between different machines, or
             when saving separate histories on  different  termi-
             nals.   Because  only  ~/.tcshrc is normally sourced
             before  ~/.history,  histfile  should  be   set   in
             ~/.tcshrc rather than ~/.login.

     histlit (+)
             If set, builtin and editor commands and the savehist
             mechanism use the literal (unexpanded) form of lines
             in the history list.  See also  the  toggle-literal-
             history editor command.

     history The first  word  indicates  the  number  of  history
             events  to save.  The optional second word (+) indi-
             cates the format in which history is printed; if not
             given, `%h\t%T\t%R\n' is used.  The format sequences
             are described below under prompt; note the  variable
             meaning of `%R'.  Set to `100' by default.

     home    Initialized to the home directory  of  the  invoker.
             The  filename  expansion of `~' refers to this vari-
             able.

     ignoreeof
             If set to the empty string or `0' and the input dev-
             ice  is a terminal, the end-of-file command (usually
             generated by the user by typing  `^D'  on  an  empty
             line) causes the shell to print `Use "exit" to leave
             tcsh.' instead of exiting.  This prevents the  shell
             from  accidentally being killed.  If set to a number
             n, the shell ignores n - 1 consecutive  end-of-files
             and  exits  on  the nth.  (+) If unset, `1' is used,
             i.e., the shell exits on a single `^D'.

     implicitcd (+)
             If set, the shell treats a directory name typed as a
             command  as  though  it  were a request to change to
             that directory.  If set to verbose,  the  change  of
             directory  is  echoed  to the standard output.  This
             behavior  is  inhibited  in  non-interactive   shell
             scripts,  or  for command strings with more than one
             word.  Changing directory takes precedence over exe-
             cuting  a  like-named  command, but it is done after
             alias substitutions.  Tilde and variable  expansions
             work as expected.

     inputmode (+)
             If set to `insert' or `overwrite', puts  the  editor
             into that input mode at the beginning of each line.

     killdup (+)
             Controls handling of duplicate entries in  the  kill
             ring.   If  set  to  `all'  only  unique strings are
             entered in the kill ring.  If set to `prev' and  the
             last killed string is the same as the current killed
             string, then the current string is  not  entered  in
             the  ring.  If set to `erase' and the same string is
             found in the kill ring, the old string is erased and
             the current one is inserted.

     killring (+)
             Indicates the number of killed strings  to  keep  in
             memory.  Set to `30' by default.  If unset or set to
             less than `2', the shell will  only  keep  the  most
             recently killed string.

     listflags (+)
             If set to  `x',  `a'  or  `A',  or  any  combination
             thereof  (e.g.,  `xA'),  they  are  used as flags to
             ls-F, making it act like `ls  -xF',  `ls  -Fa',  `ls
             -FA'  or  a combination (e.g., `ls -FxA'): `a' shows
             all files (even if they start with a `.'), `A' shows
             all  files  but  `.'  and `..', and `x' sorts across
             instead of down.  If the second word of listflags is
             set, it is used as the path to `ls(1)'.

     listjobs (+)
             If set, all jobs are listed when a job is suspended.
             If set to `long', the listing is in long format.

     listlinks (+)
             If set, the ls-F builtin command shows the  type  of
             file to which each symbolic link points.

     listmax (+)
             The maximum number of items which  the  list-choices
             editor command will list without asking first.

     listmaxrows (+)
             The maximum number of rows of items which the  list-
             choices  editor  command  will  list  without asking
             first.

     loginsh (+)
             Set by the shell if it is a login shell.  Setting or
             unsetting it within a shell has no effect.  See also
             shlvl.

     logout (+)
             Set by the shell to `normal' before a normal logout,
             `automatic' before an automatic logout, and `hangup'
             if the shell was killed by a hangup signal (see Sig-
             nal  handling).  See also the autologout shell vari-
             able.

     mail    The names of the files or directories to  check  for
             incoming  mail, separated by whitespace, and option-
             ally  preceded  by  a  numeric  word.   Before  each
             prompt,  if  10  minutes  have passed since the last
             check, the shell checks each file and says `You have
             new  mail.'  (or,  if  mail contains multiple files,
             `You have new mail in name.')  if  the  filesize  is
             greater  than  zero  in  size and has a modification
             time greater than its access time.

             If you are in a login shell, then no  mail  file  is
             reported  unless it has been modified after the time
             the shell  has  started  up,  to  prevent  redundant
             notifications.   Most  login  programs will tell you
             whether or not you have mail when you log in.

             If a file specified in  mail  is  a  directory,  the
             shell  will count each file within that directory as
             a separate message, and  will  report  `You  have  n
             mails.'  or `You have n mails in name.' as appropri-
             ate.  This functionality is provided  primarily  for
             those  systems which store mail in this manner, such
             as the Andrew Mail System.

             If the first word of mail is numeric it is taken  as
             a different mail checking interval, in seconds.

             Under very rare circumstances, the shell may  report
             `You have mail.' instead of `You have new mail.'

     matchbeep (+)
             If set to `never', completion never beeps.   If  set
             to  `nomatch', it beeps only when there is no match.
             If set to `ambiguous, it beeps when there are multi-
             ple  matches.   If set to `notunique', it beeps when
             there is one exact and  other  longer  matches.   If
             unset, `ambiguous' is used.

     nobeep (+)
             If set, beeping is completely  disabled.   See  also
             visiblebell.

     noclobber
             If set, restrictions are placed on  output  redirec-
             tion  to insure that files are not accidentally des-
             troyed and that `>>' redirections refer to  existing
             files, as described in the Input/output section.

     noding  If set, disable  the  printing  of  `DING!'  in  the
             prompt time specifiers at the change of hour.

     noglob  If set, Filename substitution  and  Directory  stack
             substitution  (q.v.)  are  inhibited.   This is most
             useful in shell  scripts  which  do  not  deal  with
             filenames,  or  after  a  list of filenames has been
             obtained and further expansions are not desirable.

     nokanji (+)
             If set and the shell supports Kanji (see the version
             shell variable), it is disabled so that the meta key
             can be used.

     nonomatch
             If set, a Filename substitution or  Directory  stack
             substitution  (q.v.) which does not match any exist-
             ing files is left untouched rather than  causing  an
             error.  It is still an error for the substitution to
             be malformed, e.g., `echo [' still gives an error.

     nostat (+)
             A list of directories (or glob-patterns which  match
             directories;  see Filename substitution) that should
             not be  stat(2)ed  during  a  completion  operation.
             This  is  usually  used to exclude directories which
             take too much time to stat(2), for example /afs.

     notify  If set, the shell announces  job  completions  asyn-
             chronously.   The  default is to present job comple-
             tions just before printing a prompt.

     oid (+) The user's real organization ID.  (Domain/OS only)

     owd (+) The old working directory,  equivalent  to  the  `-'
             used by cd and pushd.  See also the cwd and dirstack
             shell variables.

     path    A list of directories in which to look  for  execut-
             able  commands.   A  null word specifies the current
             directory.  If there is no path variable  then  only
             full  path  names  will execute.  path is set by the
             shell at startup from the PATH environment  variable
             or,  if  PATH  does not exist, to a system-dependent
             default  something  like  `(/usr/local/bin  /usr/bsd
             /bin  /usr/bin  .)'.  The shell may put `.' first or
             last in path or omit it entirely depending on how it
             was  compiled;  see  the  version shell variable.  A
             shell which is given  neither  the  -c  nor  the  -t
             option  hashes  the  contents  of the directories in
             path after reading ~/.tcshrc and each time  path  is
             reset.   If one adds a new command to a directory in
             path while the shell is active, one may need to do a
             rehash for the shell to find it.

     printexitvalue (+)
             If set and an interactive program exits with a  non-
             zero status, the shell prints `Exit status'.

     prompt  The string which is printed before reading each com-
             mand  from  the terminal.  prompt may include any of
             the following formatting sequences  (+),  which  are
             replaced by the given information:
             %/  The current working directory.
             %~  The current working directory,  but  with  one's
                 home  directory  represented  by  `~'  and other
                 users' home directories represented  by  `~user'
                 as per Filename substitution.  `~user' substitu-
                 tion happens only if the shell has already  used
                 `~user' in a pathname in the current session.
             %c[[0]n], %.[[0]n]
                 The trailing component of  the  current  working
                 directory, or n trailing components if a digit n
                 is given.  If n begins with `0', the  number  of
                 skipped    components   precede   the   trailing
                 component(s) in the format `/<skipped>trailing'.
                 If  the  ellipsis shell variable is set, skipped
                 components are represented by an ellipsis so the
                 whole  becomes  `...trailing'.  `~' substitution
                 is done as in `%~' above, but the `~'  component
                 is ignored when counting trailing components.
             %C  Like %c, but without `~' substitution.
             %h, %!, !
                 The current history event number.
             %M  The full hostname.
             %m  The hostname up to the first `.'.
             %S (%s)
                 Start (stop) standout mode.
             %B (%b)
                 Start (stop) boldfacing mode.
             %U (%u)
                 Start (stop) underline mode.
             %t, %@
                 The time of day in 12-hour AM/PM format.
             %T  Like `%t', but in 24-hour format  (but  see  the
                 ampm shell variable).
             %p  The `precise' time of day in 12-hour AM/PM  for-
                 mat, with seconds.
             %P  Like `%p', but in 24-hour format  (but  see  the
                 ampm shell variable).
             \c  c is parsed as in bindkey.
             ^c  c is parsed as in bindkey.
             %%  A single `%'.
             %n  The user name.
             %j  The number of jobs.
             %d  The weekday in `Day' format.
             %D  The day in `dd' format.
             %w  The month in `Mon' format.
             %W  The month in `mm' format.
             %y  The year in `yy' format.
             %Y  The year in `yyyy' format.
             %l  The shell's tty.
             %L  Clears from the end of the prompt to end of  the
                 display or the end of the line.
             %$  Expands the shell or environment  variable  name
                 immediately after the `$'.
             %#  `>' (or the first character of  the  promptchars
                 shell  variable)  for  normal users, `#' (or the
                 second  character  of   promptchars)   for   the
                 superuser.
             %{string%}
                 Includes string as a  literal  escape  sequence.
                 It should be used only to change terminal attri-
                 butes and should not move the  cursor  location.
                 This cannot be the last sequence in prompt.
             %?  The return code of  the  command  executed  just
                 before the prompt.
             %R  In  prompt2,  the  status  of  the  parser.   In
                 prompt3,  the corrected string.  In history, the
                 history string.

             `%B', `%S', `%U' and `%{string%}' are  available  in
             only  eight-bit-clean  shells; see the version shell
             variable.

             The bold, standout and underline sequences are often
             used to distinguish a superuser shell.  For example,

                 > set prompt = "%m [%h] %B[%@]%b [%/] you  rang?
                 "
                 tut [37] [2:54pm] [/usr/accts/sys] you rang? _

             If `%t', `%@', `%T', `%p', or `%P' is used, and nod-
             ing  is not set, then print `DING!' on the change of
             hour (i.e, `:00'  minutes)  instead  of  the  actual
             time.

             Set by default to `%# ' in interactive shells.

     prompt2 (+)
             The string with which to prompt in while and foreach
             loops  and after lines ending in `\'.  The same for-
             mat sequences may be used as in prompt (q.v.);  note
             the  variable  meaning  of  `%R'.  Set by default to
             `%R? ' in interactive shells.

     prompt3 (+)
             The string with  which  to  prompt  when  confirming
             automatic  spelling  correction.   The  same  format
             sequences may be used as in prompt (q.v.); note  the
             variable   meaning  of  `%R'.   Set  by  default  to
             `CORRECT>%R (y|n|e|a)? ' in interactive shells.

     promptchars (+)
             If set (to a two-character string), the `%#' format-
             ting  sequence  in  the  prompt  shell  variable  is
             replaced with the first character for  normal  users
             and the second character for the superuser.

     pushdtohome (+)
             If set, pushd without arguments does `pushd ~', like
             cd.

     pushdsilent (+)
             If set, pushd and popd do not  print  the  directory
             stack.

     recexact (+)
             If set, completion completes on an exact match  even
             if a longer match is possible.

     recognize_only_executables (+)
             If set, command listing displays only files  in  the
             path that are executable.  Slow.

     rmstar (+)
             If set, the user is prompted before `rm *'  is  exe-
             cuted.

     rprompt (+)
             The string to print on the right-hand  side  of  the
             screen  (after the command input) when the prompt is
             being displayed on the left.  It recognizes the same
             formatting  characters as prompt.  It will automati-
             cally disappear and reappear as necessary, to ensure
             that  command  input isn't obscured, and will appear
             only if the prompt, command input, and  itself  will
             fit  together on the first line.  If edit isn't set,
             then rprompt will be printed after  the  prompt  and
             before the command input.

     savedirs (+)
             If set, the shell does `dirs -S' before exiting.  If
             the first word is set to a number, at most that many
             directory stack entries are saved.

     savehist
             If set, the shell does `history -S' before  exiting.
             If  the  first word is set to a number, at most that
             many lines are saved.  (The number must be less than
             or  equal to history.)  If the second word is set to
             `merge', the history list is merged with the  exist-
             ing  history  file instead of replacing it (if there
             is one) and sorted by time stamp and the most recent
             events are retained.  (+)

     sched (+)
             The format in which the sched builtin command prints
             scheduled  events;  if  not given, `%h\t%T\t%R\n' is
             used.  The  format  sequences  are  described  above
             under prompt; note the variable meaning of `%R'.

     shell   The file in which the shell resides.  This  is  used
             in forking shells to interpret files which have exe-
             cute bits set, but which are not executable  by  the
             system.   (See  the  description of Builtin and non-
             builtin  command  execution.)   Initialized  to  the
             (system-dependent) home of the shell.

     shlvl (+)
             The number of nested shells.  Reset to  1  in  login
             shells.  See also loginsh.

     status  The status returned by the last command.  If it ter-
             minated  abnormally,  then  0200  is  added  to  the
             status.  Builtin commands  which  fail  return  exit
             status `1', all other builtin commands return status
             `0'.

     symlinks (+)
             Can be set to several different  values  to  control
             symbolic link (`symlink') resolution:

             If set to `chase', whenever  the  current  directory
             changes  to  a directory containing a symbolic link,
             it is expanded to the real name of the directory  to
             which  the  link points.  This does not work for the
             user's home directory; this is a bug.

             If set to `ignore', the shell tries to  construct  a
             current  directory relative to the current directory
             before the link was crossed.  This means that  cding
             through  a symbolic link and then `cd ..'ing returns
             one to the original directory.   This  affects  only
             builtin commands and filename completion.

             If set to `expand', the shell tries to fix  symbolic
             links  by  actually  expanding  arguments which look
             like path names.  This affects any command, not just
             builtins.   Unfortunately,  this  does  not work for
             hard-to-recognize filenames, such as those  embedded
             in  command  options.  Expansion may be prevented by
             quoting.  While this setting  is  usually  the  most
             convenient, it is sometimes misleading and sometimes
             confusing when it fails  to  recognize  an  argument
             which  should  be  expanded.  A compromise is to use
             `ignore' and use the editor  command  normalize-path
             (bound by default to ^X-n) when necessary.

             Some examples are in order.   First,  let's  set  up
             some play directories:
                 > cd /tmp
                 > mkdir from from/src to
                 > ln -s from/src to/dist

             Here's the behavior with symlinks unset,

                 > cd /tmp/to/dist; echo $cwd
                 /tmp/to/dist
                 > cd ..; echo $cwd
                 /tmp/from

             here's the behavior with symlinks set to `chase',

                 > cd /tmp/to/dst; echo $cwd
                 /tmp/from/src
                 > cd ..; echo $cwd
                 /tmp/from

             here's the behavior with symlinks set to `ignore',

                 > cd /tmp/to/dist; echo $cwd
                 /tmp/to/dst
                 > cd ..; echo $cwd
                 /tmp/to

             and  here's  the  behavior  with  symlinks  set   to
             `expand'.

                 > cd /tmp/to/dist; echo $cwd
                 /tmp/to/dst
                 > cd ..; echo $cwd
                 /tmp/to
                 > cd /tmp/to/dist; echo $cwd
                 /tmp/to/dst
                 > cd ".."; echo $cwd
                 /tmp/from
                 > /bin/echo ..
                 /tmp/to
                 > /bin/echo ".."
                 ..

             Note that `expand'  expansion  1)  works  just  like
             `ignore'  for  builtins  like cd, 2) is prevented by
             quoting, and 3) happens before filenames are  passed
             to non-builtin commands.

     tcsh (+)
             The version  number  of  the  shell  in  the  format
             `R.VV.PP',  where  `R'  is the major release number,
             `VV' the current version and `PP' the patchlevel.

     term    The terminal  type.   Usually  set  in  ~/.login  as
             described under Startup and shutdown.

     time    If set to a number, then  the  time  builtin  (q.v.)
             executes  automatically  after  each  command  which
             takes more than that many CPU seconds.  If there  is
             a second word, it is used as a format string for the
             output of  the  time  builtin.   (u)  The  following
             sequences may be used in the format string:

             %U  The time the process spent in user mode  in  cpu
                 seconds.
             %S  The time the process spent in kernel mode in cpu
                 seconds.
             %E  The elapsed (wall clock) time in seconds.
             %P  The CPU percentage computed as (%U + %S) / %E.
             %W  Number of times the process was swapped.
             %X  The average amount in (shared) text  space  used
                 in Kbytes.
             %D  The  average  amount  in  (unshared)  data/stack
                 space used in Kbytes.
             %K  The total space used (%X + %D) in Kbytes.
             %M  The maximum memory the process had in use at any
                 time in Kbytes.
             %F  The number of major page faults (page needed  to
                 be brought from disk).
             %R  The number of minor page faults.
             %I  The number of input operations.
             %O  The number of output operations.
             %r  The number of socket messages received.
             %s  The number of socket messages sent.
             %k  The number of signals received.
             %w  The  number  of   voluntary   context   switches
                 (waits).
             %c  The number of involuntary context switches.

             Only the first four sequences are supported on  sys-
             tems  without  BSD  resource  limit  functions.  The
             default time format is `%Uu %Ss %E %P %X+%Dk %I+%Oio
             %Fpf+%Ww'  for  systems  that support resource usage
             reporting and `%Uu %Ss %E %P' for  systems  that  do
             not.

             Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are
             not   available,   but   the   following  additional
             sequences are:

             %Y  The number of system calls performed.
             %Z  The number of pages  which  are  zero-filled  on
                 demand.
             %i  The number of times  a  process's  resident  set
                 size was increased by the kernel.
             %d  The number of times  a  process's  resident  set
                 size was decreased by the kernel.
             %l  The number of read system calls performed.
             %m  The number of write system calls performed.
             %p  The number of reads from raw disk devices.
             %q  The number of writes to raw disk devices.

             and the default  time  format  is  `%Uu  %Ss  $E  %P
             %I+%Oio %Fpf+%Ww'.  Note that the CPU percentage can
             be higher than 100% on multi-processors.

     tperiod (+)
             The period, in minutes, between  executions  of  the
             periodic special alias.

     tty (+) The name of the tty, or empty  if  not  attached  to
             one.

     uid (+) The user's real user ID.

     user    The user's login name.

     verbose If set, causes the  words  of  each  command  to  be
             printed,  after  history substitution (if any).  Set
             by the -v command line option.

     version (+)
             The version ID stamp.  It contains the shell's  ver-
             sion  number  (see tcsh), origin, release date, ven-
             dor,  operating  system  and  machine  (see  VENDOR,
             OSTYPE  and  MACHTYPE) and a comma-separated list of
             options which were set  at  compile  time.   Options
             which  are  set  by  default in the distribution are
             noted.

             8b  The shell is eight bit clean; default
             7b  The shell is not eight bit clean
             nls The system's NLS is used;  default  for  systems
                 with NLS
             lf  Login shells execute /etc/.login before  instead
                 of after /etc/.cshrc and ~/.login before instead
                 of after ~/.tcshrc and ~/.history.
             dl  `.' is put last in path for security; default
             nd  `.' is omitted from path for security
             vi  vi-style editing  is  the  default  rather  than
                 emacs
             dtr Login shells drop DTR when exiting
             bye bye is a synonym for logout and log is an alter-
                 nate name for watchlog
             al  autologout is enabled; default
             kan Kanji is used if appropriate according to locale
                 settings,  unless  the nokanji shell variable is
                 set

             sm  The system's malloc(3C) is used
             hb  The `#!<program> <args>' convention is  emulated
                 when executing shell scripts
             ng  The newgrp builtin is available
             rh  The  shell  attempts  to  set   the   REMOTEHOST
                 environment variable
             afs The shell verifies your password with  the  ker-
                 beros server if local authentication fails.  The
                 afsuser shell variable or the  AFSUSER  environ-
                 ment  variable  override  your local username if
                 set.

             An administrator may  enter  additional  strings  to
             indicate differences in the local version.

     visiblebell (+)
             If set, a screen flash is used rather than the audi-
             ble bell.  See also nobeep.

     watch (+)
             A list of user/terminal pairs to  watch  for  logins
             and logouts.  If either the user is `any' all termi-
             nals are watched for the given user and vice  versa.
             Setting  watch  to `(any any)' watches all users and
             terminals.  For example,

                 set watch = (george ttyd1 any console $user any)

             reports activity of the user `george' on ttyd1,  any
             user  on  the console, and oneself (or a trespasser)
             on any terminal.

             Logins and logouts are checked every 10  minutes  by
             default, but the first word of watch can be set to a
             number to check every so many minutes.  For example,

                 set watch = (1 any any)

             reports any login/logout once every minute.  For the
             impatient,  the log builtin command triggers a watch
             report at any time.  All current logins are reported
             (as with the log builtin) when watch is first set.

             The who shell variable controls the format of  watch
             reports.

     who (+) The format string for watch messages.  The following
             sequences are replaced by the given information:

             %n  The name of the user who logged in/out.
             %a  The observed action, i.e., `logged on',  `logged
                 off' or `replaced olduser on'.

             %l  The terminal (tty)  on  which  the  user  logged
                 in/out.
             %M  The full hostname of the remote host, or `local'
                 if the login/logout was from the local host.
             %m  The hostname of the remote host up to the  first
                 `.'.   The  full  name is printed if it is an IP
                 address or an X Window System display.

             %M and %m are available on only systems  that  store
             the  remote hostname in /etc/utmp or /etc/utmpx.  If
             unset, `%n has %a %l from %m.' is used, or  `%n  has
             %a  %l.'  on  systems  which  don't store the remote
             hostname.

     wordchars (+)
             A list of non-alphanumeric  characters  to  be  con-
             sidered   part   of  a  word  by  the  forward-word,
             backward-word  etc.,  editor  commands.   If  unset,
             `*?_-.[]~=' is used.

ENVIRONMENT
     AFSUSER (+)
             Equivalent to the afsuser shell variable.

     COLUMNS The number of columns in the terminal.  See Terminal
             management.

     DISPLAY Used by X Window System (see  X(7)).   If  set,  the
             shell does not set autologout (q.v.).

     EDITOR  The pathname to a  default  editor.   See  also  the
             VISUAL  environment  variable  and the run-fg-editor
             editor command.

     GROUP (+)
             Equivalent to the group shell variable.

     HOME    Equivalent to the home shell variable.

     HOST (+)
             Initialized to the name of the machine on which  the
             shell    is    running,   as   determined   by   the
             gethostname(3C) system call.

     HOSTTYPE (+)
             Initialized to the type  of  machine  on  which  the
             shell  is  running,  as  determined at compile time.
             This variable is obsolete and will be removed  in  a
             future version.

     HPATH (+)
             A colon-separated list of directories in  which  the
             run-help editor command looks for command documenta-
             tion.

     LANG    Gives  the  preferred  character  environment.   See
             Native Language System support.

     LC_CTYPE
             If set, only ctype character  handling  is  changed.
             See Native Language System support.

     LINES   The number of lines in the terminal.   See  Terminal
             management.

     LS_COLORS
             The format of this variable is  reminiscent  of  the
             termcap(5)  file  format;  a colon-separated list of
             expressions of the form "xx=string", where "xx" is a
             two-character  variable  name.   The  variables with
             their associated defaults are:

                 no   0      Normal (non-filename) text
                 fi   0      Regular file
                 di   01;34  Directory
                 ln   01;36  Symbolic link
                 pi   33     Named pipe (FIFO)
                 so   01;35  Socket
                 do      01;35
                             Door
                 bd   01;33  Block device
                 cd   01;32  Character device
                 ex   01;32  Executable file
                 mi   (none) Missing file (defaults to fi)
                 or   (none) Orphaned symbolic link (defaults  to
                             ln)
                 lc   ^[[    Left code
                 rc   m      Right code
                 ec   (none) End code (replaces lc+no+rc)

             You need to include only the variables you  want  to
             change from the default.

             File names can also be colorized based  on  filename
             extension.  This is specified in the LS_COLORS vari-
             able using the syntax "*ext=string".   For  example,
             using ISO 6429 codes, to color all C-language source
             files blue you would specify "*.c=34".   This  would
             color all files ending in .c in blue (34) color.

             Control  characters  can  be   written   either   in
             C-style-escaped  notation,  or  in stty-like ^-nota-
             tion.  The C-style notation adds ^[  for  Escape,  _
             for  a normal space character, and ? for Delete.  In
             addition, the ^[ escape character  can  be  used  to
             override  the default interpretation of ^[, ^, : and
             =.

             Each file will be written as <lc> <color-code>  <rc>
             <filename> <ec>.  If the <ec> code is undefined, the
             sequence <lc> <no> <rc> will be used instead.   This
             is  generally  more convenient to use, but less gen-
             eral.  The left, right and end codes are provided so
             you  don't  have  to type common parts over and over
             again and to support weird terminals; you will  gen-
             erally  not  need  to change them at all unless your
             terminal does not use ISO 6429 color sequences but a
             different system.

             If your terminal does use ISO 6429 color codes,  you
             can compose the type codes (i.e., all except the lc,
             rc, and ec codes) from numerical commands  separated
             by semicolons.  The most common commands are:

                     0   to restore default color
                     1   for brighter colors
                     4   for underlined text
                     5   for flashing text
                     30  for black foreground
                     31  for red foreground
                     32  for green foreground
                     33  for yellow (or brown) foreground
                     34  for blue foreground
                     35  for purple foreground
                     36  for cyan foreground
                     37  for white (or gray) foreground
                     40  for black background
                     41  for red background
                     42  for green background
                     43  for yellow (or brown) background
                     44  for blue background
                     45  for purple background
                     46  for cyan background
                     47  for white (or gray) background

             Not all commands will work on all systems or display
             devices.

             A few terminal programs do not recognize the default
             end code properly.  If all text gets colorized after
             you do a directory listing, try changing the no  and
             fi  codes  from  0  to  the numerical codes for your
             standard fore- and background colors.

     MACHTYPE (+)
             The machine type (microprocessor  class  or  machine
             model), as determined at compile time.

     NOREBIND (+)
             If set, printable  characters  are  not  rebound  to
             self-insert-command.   See  Native  Language  System
             support.

     OSTYPE (+)
             The operating system, as determined at compile time.

     PATH    A colon-separated list of directories  in  which  to
             look  for executables.  Equivalent to the path shell
             variable, but in a different format.

     PWD (+) Equivalent to the cwd shell variable, but  not  syn-
             chronized to it; updated only after an actual direc-
             tory change.

     REMOTEHOST (+)
             The host from which the user has logged in remotely,
             if  this is the case and the shell is able to deter-
             mine it.  Set only if the shell was so compiled; see
             the version shell variable.

     SHLVL (+)
             Equivalent to the shlvl shell variable.

     SYSTYPE (+)
             The current system type.  (Domain/OS only)

     TERM    Equivalent to the term shell variable.

     TERMCAP The  terminal  capability  string.    See   Terminal
             management.

     USER    Equivalent to the user shell variable.

     VENDOR (+)
             The vendor, as determined at compile time.

     VISUAL  The pathname to a default full-screen  editor.   See
             also  the  EDITOR  environment variable and the run-
             fg-editor editor command.

FILES
     /etc/csh.cshrc  Read first by every shell.  ConvexOS,  Stel-
                     lix  and  Intel use /etc/cshrc and NeXTs use
                     /etc/cshrc.std.  A/UX, AMIX, Cray  and  IRIX
                     have  no equivalent in csh(1), but read this
                     file in tcsh anyway.  Solaris does not  have
                     it either, but tcsh reads /etc/.cshrc.  (+)
     /etc/csh.login  Read by login shells  after  /etc/csh.cshrc.
                     ConvexOS,  Stellix and Intel use /etc/login,
                     NeXTs  use  /etc/login.std,   Solaris   uses
                     /etc/.login  and  A/UX,  AMIX, Cray and IRIX
                     use /etc/cshrc.
     ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc  or
                     its equivalent.
     ~/.cshrc        Read by every shell,  if  ~/.tcshrc  doesn't
                     exist,    after    /etc/csh.cshrc   or   its
                     equivalent.  This manual uses `~/.tcshrc' to
                     mean  `~/.tcshrc  or,  if  ~/.tcshrc  is not
                     found, ~/.cshrc'.
     ~/.history      Read by  login  shells  after  ~/.tcshrc  if
                     savehist is set, but see also histfile.
     ~/.login        Read by  login  shells  after  ~/.tcshrc  or
                     ~/.history.   The  shell  may be compiled to
                     read  ~/.login  before  instead   of   after
                     ~/.tcshrc  and  ~/.history;  see the version
                     shell variable.
     ~/.cshdirs (+)  Read  by  login  shells  after  ~/.login  if
                     savedirs is set, but see also dirsfile.
     /etc/csh.logout Read by login shells at  logout.   ConvexOS,
                     Stellix  and Intel use /etc/logout and NeXTs
                     use /etc/logout.std.  A/UX, AMIX,  Cray  and
                     IRIX  have no equivalent in csh(1), but read
                     this file in tcsh anyway.  Solaris 2.x  does
                     not   have   it   either,   but  tcsh  reads
                     /etc/.logout.  (+)
     ~/.logout       Read  by  login  shells  at   logout   after
                     /etc/csh.logout or its equivalent.
     /bin/sh         Used to interpret shell scripts not starting
                     with a `#'.
     /tmp/sh*        Temporary file for `<<'.
     /etc/passwd     Source of home directories for `~name'  sub-
                     stitutions.

     The order in which startup files are read may differ if  the
     shell was so compiled; see Startup and shutdown and the ver-
     sion shell variable.

NEW FEATURES (+)
     This manual describes tcsh as a single entity,  but  experi-
     enced  csh(1)  users  will  want to pay special attention to
     tcsh's new features.

     A command-line editor, which supports GNU  Emacs  or  vi(1)-
     style  key bindings.  See The command-line editor and Editor
     commands.

     Programmable, interactive word completion and listing.   See
     Completion and listing and the complete and uncomplete buil-
     tin commands.

     Spelling correction (q.v.) of filenames, commands and  vari-
     ables.

     Editor commands (q.v.) which perform other useful  functions
     in  the  middle  of  typed commands, including documentation
     lookup (run-help), quick editor  restarting  (run-fg-editor)
     and command resolution (which-command).

     An enhanced history mechanism.  Events in the  history  list
     are  time-stamped.   See  also  the  history command and its
     associated shell variables, the previously undocumented  `#'
     event  specifier  and  new modifiers under History substitu-
     tion,  the  *-history,  history-search-*,  i-search-*,   vi-
     search-*  and toggle-literal-history editor commands and the
     histlit shell variable.

     Enhanced directory parsing  and  directory  stack  handling.
     See  the cd, pushd, popd and dirs commands and their associ-
     ated shell variables, the  description  of  Directory  stack
     substitution, the dirstack, owd and symlinks shell variables
     and the normalize-command  and  normalize-path  editor  com-
     mands.

     Negation in glob-patterns.  See Filename substitution.

     New File inquiry operators (q.v.)  and  a  filetest  builtin
     which uses them.

     A variety of Automatic, periodic  and  timed  events  (q.v.)
     including   scheduled  events,  special  aliases,  automatic
     logout and terminal locking, command timing and watching for
     logins and logouts.

     Support for the Native Language System (see Native  Language
     System support), OS variant features (see OS variant support
     and the echo_style shell variable) and system-dependent file
     locations (see FILES).

     Extensive terminal-management  capabilities.   See  Terminal
     management.

     New builtin commands including builtins, hup, ls-F,  newgrp,
     printenv, which and where (q.v.).

     New variables that make useful information easily  available
     to  the shell.  See the gid, loginsh, oid, shlvl, tcsh, tty,
     uid and version shell variables and  the  HOST,  REMOTEHOST,
     VENDOR, OSTYPE and MACHTYPE environment variables.

     A new syntax for including useful information in the  prompt
     string  (see  prompt).   and  special  prompts for loops and
     spelling correction (see prompt2 and prompt3).
     Read-only variables.  See Variable substitution.

BUGS
     When a suspended command is restarted, the shell prints  the
     directory  it  started  in  if  this  is  different from the
     current directory.  This can be misleading (i.e., wrong)  as
     the job may have changed directories internally.

     Shell builtin functions are not stoppable/restartable.  Com-
     mand  sequences of the form `a ; b ; c' are also not handled
     gracefully when stopping is attempted.  If you suspend  `b',
     the  shell will then immediately execute `c'.  This is espe-
     cially noticeable if this expansion results from  an  alias.
     It  suffices  to  place  the sequence of commands in ()'s to
     force it to a subshell, i.e., `( a ; b ; c )'.

     Control over tty output after processes are started is prim-
     itive;  perhaps  this will inspire someone to work on a good
     virtual terminal interface.  In a virtual terminal interface
     much  more interesting things could be done with output con-
     trol.

     Alias substitution is most often used to  clumsily  simulate
     shell procedures; shell procedures should be provided rather
     than aliases.

     Commands within loops are not placed in  the  history  list.
     Control structures should be parsed rather than being recog-
     nized as built-in commands.  This would allow  control  com-
     mands to be placed anywhere, to be combined with `|', and to
     be used with `&' and `;' metasyntax.

     foreach doesn't ignore here documents when looking  for  its
     end.

     It should be possible to use the `:' modifiers on the output
     of command substitutions.

     The screen update for lines longer than the screen width  is
     very  poor  if the terminal cannot move the cursor up (i.e.,
     terminal type `dumb').

     HPATH and NOREBIND don't need to be environment variables.

     Glob-patterns which do not use `?', `*' or `[]' or which use
     `{}' or `~' are not negated correctly.

     The single-command form of if does output  redirection  even
     if the expression is false and the command is not executed.

     ls-F includes file identification  characters  when  sorting
     filenames   and   does  not  handle  control  characters  in
     filenames well.  It cannot be interrupted.

     Report bugs to tcsh-bugs@mx.gw.com, preferably  with  fixes.
     If  you  want  to  help maintain and test tcsh, send mail to
     listserv@mx.gw.com  with  the  text  `subscribe  tcsh  <your
     name>'  on a line by itself in the body.  You can also `sub-
     scribe tcsh-bugs <your name>' to get  all  bug  reports,  or
     `subscribe  tcsh-diffs  <your  name>' to get the development
     list plus diffs for each patchlevel.

THE T IN TCSH
     In 1964, DEC produced the PDP-6.  The  PDP-10  was  a  later
     re-implementation.  It was re-christened the DECsystem-10 in
     1970 or so when DEC brought out the second model, the KI10.

     TENEX was created at Bolt, Beranek &  Newman  (a  Cambridge,
     Massachusetts  think  tank)  in  1972  as  an  experiment in
     demand-paged virtual memory operating systems.  They built a
     new  pager  for the DEC PDP-10 and created the OS to go with
     it.  It was extremely successful in academia.

     In 1975, DEC brought out a new  model  of  the  PDP-10,  the
     KL10;  they  intended to have only a version of TENEX, which
     they had licensed from BBN, for the new  box.   They  called
     their version TOPS-20 (their capitalization is trademarked).
     A lot of TOPS-10 users (`The OPerating System  for  PDP-10')
     objected;  thus DEC found themselves supporting two incompa-
     tible systems on the same hardware--but then there were 6 on
     the PDP-11!

     TENEX, and TOPS-20 to version 3, had command completion  via
     a  user-code-level  subroutine  library called ULTCMD.  With
     version 3, DEC moved all that capability and more  into  the
     monitor  (`kernel'  for  you  Unix  types),  accessed by the
     COMND% JSYS (`Jump to SYStem'  instruction,  the  supervisor
     call mechanism [are my IBM roots also showing?]).

     The creator of  tcsh  was  impressed  by  this  feature  and
     several  others  of TENEX and TOPS-20, and created a version
     of csh which mimicked them.

LIMITATIONS
     Words can be no longer than 1024 characters.

     The system limits argument lists to 10240 characters.

     The number of arguments to a command which involves filename
     expansion  is  limited  to  1/6th  the  number of characters
     allowed in an argument list.

     Command substitutions may substitute no more characters than
     are allowed in an argument list.
     To detect looping, the shell restricts the number  of  alias
     substitutions on a single line to 20.

SEE ALSO
     csh(1), ls(1), newgrp(1), sh(1), stty(1), su(1M),  tset(1B),
     vi(1),  access(2),  execve(2), fork(2), killpg(3C), pipe(2),
     setrlimit(2),  sigvec(3UCB),  stat(2),  umask(2),  vfork(2),
     wait(2),  malloc(3C), setlocale(3C), tty(7D), a.out(4), ter-
     minfo(4), environ(5),  termio(7I),  Introduction  to  the  C
     Shell

VERSION
     This manual documents tcsh 6.12.00 (Astron) 2002-07-23.

AUTHORS
     William Joy
       Original author of csh(1)
     J.E. Kulp, IIASA, Laxenburg, Austria
       Job control and directory stack features
     Ken Greer, HP Labs, 1981
       File name completion
     Mike Ellis, Fairchild, 1983
       Command name recognition/completion
     Paul Placeway, Ohio State CIS Dept., 1983-1993
       Command line editor, prompt routines, new glob syntax  and
       numerous fixes and speedups
     Karl Kleinpaste, CCI 1983-4
       Special  aliases,  directory   stack   extraction   stuff,
       login/logout  watch, scheduled events, and the idea of the
       new prompt format
     Rayan Zachariassen, University of Toronto, 1984
       ls-F and which builtins and numerous bug fixes,  modifica-
       tions and speedups
     Chris Kingsley, Caltech
       Fast storage allocator routines
     Chris Grevstad, TRW, 1987
       Incorporated 4.3BSD csh into tcsh
     Christos S. Zoulas, Cornell U. EE Dept., 1987-94
       Ports to HPUX, SVR2 and SVR3, a SysV version  of  getwd.c,
       SHORT_STRINGS support and a new version of sh.glob.c
     James J Dempsey, BBN, and Paul Placeway, OSU, 1988
       A/UX port
     Daniel Long, NNSC, 1988
       wordchars
     Patrick Wolfe, Kuck and Associates, Inc., 1988
       vi mode cleanup
     David C Lawrence, Rensselaer Polytechnic Institute, 1989
       autolist and ambiguous completion listing
     Alec Wolman, DEC, 1989
       Newlines in the prompt
     Matt Landau, BBN, 1989
       ~/.tcshrc

     Ray Moody, Purdue Physics, 1989
       Magic space bar history expansion
     Mordechai ????, Intel, 1989
       printprompt() fixes and additions
     Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
       Automatic spelling correction and prompt3
     Per Hedeland, Ellemtel, Sweden, 1990-
       Various bugfixes, improvements and manual updates
     Hans J. Albertsson (Sun Sweden)
       ampm, settc and telltc
     Michael Bloom
       Interrupt handling fixes
     Michael Fine, Digital Equipment Corp
       Extended key support
     Eric Schnoebelen, Convex, 1990
       Convex support, lots of csh bug fixes, save and restore of
       directory stack
     Ron Flax, Apple, 1990
       A/UX 2.0 (re)port
     Dan Oscarsson, LTH Sweden, 1990
       NLS support and simulated NLS support for non  NLS  sites,
       fixes
     Johan Widen, SICS Sweden, 1990
       shlvl, Mach support, correct-line, 8-bit printing
     Matt Day, Sanyo Icon, 1990
       POSIX termio support, SysV limit fixes
     Jaap Vermeulen, Sequent, 1990-91
       Vi mode fixes, expand-line, window change fixes,  Symmetry
       port
     Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
       autolist beeping options, modified the history  search  to
       search for the whole string from the beginning of the line
       to the cursor.
     Scott Krotz, Motorola, 1991
       Minix port
     David Dawes, Sydney U. Australia, Physics Dept., 1991
       SVR4 job control fixes
     Jose Sousa, Interactive Systems Corp., 1991
       Extended vi fixes and vi delete command
     Marc Horowitz, MIT, 1991
       ANSIfication fixes, new exec hashing  code,  imake  fixes,
       where
     Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
       ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n
       addition,  and  various  other portability changes and bug
       fixes
     Jeff Fink, 1992
       complete-word-fwd and complete-word-back
     Harry C. Pulley, 1992
       Coherent port
     Andy Phillips, Mullard Space Science Lab U.K., 1992
       VMS-POSIX port

     Beto Appleton, IBM Corp., 1992
       Walking process group fixes, csh  bug  fixes,  POSIX  file
       tests, POSIX SIGHUP
     Scott Bolte, Cray Computer Corp., 1992
       CSOS port
     Kaveh R. Ghazi, Rutgers University, 1992
       Tek, m88k, Titan and  Masscomp  ports  and  fixes.   Added
       autoconf support.
     Mark Linderman, Cornell University, 1992
       OS/2 port
     Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
       Linux port
     Tim P. Starrin, NASA Langley Research Center Operations, 1993
       Read-only variables
     Dave Schweisguth, Yale University, 1993-4
       New man page and tcsh.man2html
     Larry Schwimmer, Stanford University, 1993
       AFS and HESIOD patches
     Luke Mewburn, RMIT University, 1994-6
       Enhanced directory printing in prompt, added ellipsis  and
       rprompt.
     Edward Hutchins, Silicon Graphics Inc., 1996
       Added implicit cd.
     Martin Kraemer, 1997
       Ported to Siemens Nixdorf EBCDIC machine
     Amol Deshpande, Microsoft, 1997
       Ported to WIN32 (Windows/95 and Windows/NT); wrote all the
       missing  library  and message catalog code to interface to
       Windows.
     Taga Nayuta, 1998
       Color ls additions.

THANKS TO
     Bryan Dunlap, Clayton Elwell, Karl Kleinpaste,  Bob  Manson,
     Steve  Romig,  Diana Smetters, Bob Sutterfield, Mark Verber,
     Elizabeth Zwicky and all the other people at Ohio State  for
     suggestions and encouragement

     All the people on the net, for putting  up  with,  reporting
     bugs in, and suggesting new additions to each and every ver-
     sion

     Richard M. Alderson III, for writing the `T in tcsh' section


NOTES
     Source for tcsh is available in the SUNWtcshS package.

     It is no longer possible for variables to have a  '-'  or  a
     '='  within  the  name. Any variables of this form will gen-
     erate a 'setenv: Syntax error' error message.


Man pages from Solaris 10 Update 8. See docs.sun.com and www.oracle.com for further documentation and Solaris information.
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