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tcsh(1)

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),  pro-
       grammable  word	completion (see Completion and listing), spelling cor-
       rection (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 remain-
	   ing arguments will not be interpreted as shell options.   This  may
	   be used to pass options to a shell script without confusion or pos-
	   sible 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 executed.  Any remaining argu-
	   ments 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	abnormally  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

       -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 immedi-
	   ately 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  ver-
       sion  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/csh.cshrc and /etc/csh.login.   It	then  executes	commands  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/csh.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/csh.cshrc and ~/.tcshrc or ~/.cshrc on
       startup.

       For examples of startup	files,	please	consult  http://tcshrc.source-
       forge.net.

       Commands  like  stty(1)	and  tset(1),  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

       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  vari-
       able).  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 sys-
       tem 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 commands but which deserve their own
       treatment.  Finally, Editor 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 envi-
       ronment variable) to

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

       unless doing so would alter another single-character binding.  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 description 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	recog-
       nizes  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 abbrevia-
       tion.  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
       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 mid-
       dle 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 beginning with `em'.	Completion can
       find a command in any directory in path or if given  a  full  pathname.
       Typing  `echo  $ar[tab]'  would	complete  `$ar' to `$argv' if no other
       variable 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 vari-
       able.  The first word in the buffer and the first word  following  `;',
       `|',  `|&',  `&&' or `||' is considered to be a command.  A word begin-
       ning with `$' is considered to be a variable.  Anything else is a file-
       name.  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 re-
       prints 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 comple-
       tion 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 abbreviated with `=' (see Directory stack  sub-
       stitution).  For example,

	   > 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-
       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 substitution.  fignore is ignored if only one completion
       is possible.

       If  the	complete  shell  variable  is  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.  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',

       ically  after  one hits `return'.  matchbeep can be set to make comple-
       tion beep or not beep in a variety of situations, 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 mecha-
       nism 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, commands and  variables.   Com-
       pletion	and listing do not work on glob-patterns (see Filename substi-
       tution), 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 listing 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 anything else to execute the original line
       unchanged.

       Spelling correction recognizes user-defined completions (see  the  com-
       plete  builtin  command).   If  an input word in a position 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  pos-
       sible  completions for that position, spelling correction does not reg-
       ister a misspelling.

       Like completion, spelling correction works anywhere in the line,  push-
       ing  the rest of the line to the right and possibly leaving extra char-
       acters 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.  Sugges-
       tions and improvements are welcome.

   Editor commands (+)
       `bindkey' lists	key  bindings  and  `bindkey  -l'  lists  and  briefly
       ters by default are bound to both lower- and uppercase letters for con-
       venience.

       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 incom-
	       plete word.

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

       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 preceding one for
	       which the current is a leading substring, 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 commands, 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

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

       expand-line (not bound)
	       Like expand-history, but expands history substitutions 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) con-
	       taining `*', `?', `[]' 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.  Additional  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	neces-
	       sary,  (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.
		   delete (or any character bound to backward-delete-char)
			   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 suc-
			   cessful 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-_)
       list-choices-raw (^X-^D)
	       Like list-choices, but ignores user-defined completions.

       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  inserts  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 executable.  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' set-
	       ting 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 helpcom-
	       mand is defined, it is run with the  command  name  as  a  sole
	       argument.   Else,  documentation should be in a file named com-
	       mand.help, command.1, command.6, command.8  or  command,  which
	       should  be  in one of the directories listed in the HPATH envi-
	       ronment 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  over-
	       write  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'
	       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 charac-
	       ter 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 vari-
	       able.

       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-pat-
	       tern, 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.

       yank-pop (M-y)
	       When  executed  immediately  after  a yank or another yank-pop,
	       replaces the yanked string with the next previous  string  from
	       the  killring.  This  also has the effect of rotating the kill-
	       ring, such  that  this  string  will  be  considered  the  most
	       recently  killed  by  a	later yank command. Repeating yank-pop
	       will cycle through the killring any number of times.

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

       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  charac-
       ter(s) (e.g., `$' or ``' for Variable substitution or Command substitu-
       tion 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.) History substitution is
       prevented by backslashes but not by single quotes.  Strings quoted with
       double  or  backward  quotes  undergo Variable substitution and Command
       substitution, but other substitutions are prevented.

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

       Quoting complex strings, particularly strings which themselves  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  back-
       slashes	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 performs on the
       input in the order in which they occur.	We note in  passing  the  data
       structures  involved  and the commands and variables which affect them.
       Remember that substitutions 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  con-
       secutive 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  cur-
       rent  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

       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 special 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 substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which indi-
       cates the event from which words are to be  taken,  a  ``word  designa-
       tor'',  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  carefully 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	example,  not  find  one,  but
       `!{v}doc'  would  expand  unambiguously to `vi wumpus.mandoc'.  Even in
       braces, history substitutions 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

	   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 `^-$', but returns nothing if the event  con-
		   tains only 1 word
	   x*	   Equivalent to `x-$'
	   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 previous 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	written `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 abbre-
       viated `!', an argument selector beginning with `-' will be interpreted
       as an event specification.

       A  history reference may have a word designator but no event specifica-
       tion.  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  ``modi-
       fied'',	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
		   character  `&'  in  the r is replaced by l; `\' also quotes
		   `&'.  If l is empty (``''), the l from a previous substitu-
		   tion  or the s from a previous `?s?' event specification is
		   used.  The trailing delimiter may be omitted if it is imme-
		   diately 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

       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 wum-
       pus.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 pre-
       vious example.  This is the only history substitution  which  does  not
       explicitly 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 substitutions 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  com-
       mand,  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 orig-
       inal command were the previous input line.  If the alias does not  con-
       tain a history reference, the argument list is left untouched.

       Thus  if  the  alias  for `ls' were `ls -l' the command `ls /usr' would
       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  dis-
       played  and  changed with the set and unset commands.  The system main-
       tains its own list of ``environment'' variables.   These  can  be  dis-
       played 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 variable 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  command
       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 `@' command permits
       numeric calculations to be performed and the result assigned to a vari-
       able.   Variable  values  are,  however, always represented as (zero or
       more) strings.  For the purposes of numeric operations, the null string
       is considered 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  sub-
       stitution  below) so `$' substitution does not occur there until later,
       if at all.  A `$' is passed unchanged if followed 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  vari-
       able  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  substitu-
       tion  the  variable  will expand to multiple words with each word sepa-
       rated by a blank and quoted to prevent later command or	filename  sub-
	       rated by a blank.  Braces insulate name from following  charac-
	       ters 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]
       ${name[selector]}
	       Substitutes only the selected words from  the  value  of  name.
	       The  selector  is subjected to `$' substitution 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 mod-
       ifiers 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

       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 discarded.  The output  is  vari-
       able 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 sub-
       stitution 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 charac-
       ters, 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 undisturbed.

       The  character `~' at the beginning of a filename refers to home direc-
       /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home	direc-
       tory substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `[' or `~', with
       or without `^', not to match any files.	However, 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 individual 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 dirsfile shell variables  can  be  set	to  store  the
       directory  stack  automatically on logout and restore it on login.  The
       dirstack shell variable can be examined to see the directory stack  and
       set to put arbitrary directories into the directory stack.

       The character `=' followed by one or more digits expands to an entry in
       the directory stack.  The special case `=-' expands to the last	direc-
       tory 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'.  Quoting 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.   Nonethe-
       less, it too can be prevented by quoting.

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

       joined  into  sequences with `||' or `&&', indicating, as in the C lan-
       guage, that the second is to be executed only if  the  first  fails  or
       succeeds respectively.

       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 component 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 execute.

       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 spe-
       cial alias may be set to specify an interpreter other  than  the  shell
       itself.

       On  systems which do not understand the `#!' script interpreter conven-
       tion 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 `#!interpreter 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:

	       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 stan-
	       dard 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  acciden-
	       tal  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  output.   name is
	       expanded in the same way as `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! 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 command 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 out-
       put.  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 workaround.  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
       If the shell's input is not seekable, the shell buffers up input  when-
       ever 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 `!~' oper-
       ators compare their arguments as strings; all others  operate  on  num-
       bers.   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  adjacent to components of expressions which are syntacti-
       cally 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 sta-
       tus 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 (+)
	   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	speci-
       fied 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  equiva-
       lent  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 subsequent 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 operators which  do  not,
       (e.g., X and t).  Following L with a non-file operator can lead to par-
       ticularly 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 groupname is
		   unknown
       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 inte-
       ger 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 `Sus-
       pended'	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 command 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 immedi-
       ately and is like an interrupt in that pending output and unread  input
       are  discarded  when  it is typed.  The wait builtin command 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  command.
       (+)

       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 command `stty tostop'.  If you set
       this tty option, then background jobs will stop when they try  to  pro-
       duce 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  fore-
       ground.	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 restart a suspended
       ex(1) job, if there were only one suspended job whose name  began  with
       the  string  `ex'.   It is also possible to say `%?string' to specify a
       job whose text contains string, if there is only one such job.
       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 com-
       mand for details on setting options in the new tty driver.

   Status reporting
       The shell learns immediately whenever a process changes state.  It nor-
       mally  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 automati-
       cally 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,  postcmd, and jobcmd Special
       aliases can be set, respectively, to execute commands  when  the  shell
       wants  to ring the bell, when the working directory changes, every tpe-
       riod minutes, before each prompt, before each  command  gets  executed,
       after  each  command  gets  executed,  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 builtin  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.

       respects.

       When  using  the  system's  NLS, the setlocale(3) function is called to
       determine appropriate character classification and sorting.  This func-
       tion  typically	examines  the LANG and LC_CTYPE environment variables;
       refer to the system documentation 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  bind-
       ing for the escape-char sequence, if any, is left alone.  These charac-
       ters 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 bindings in  the  range
       \240-\377  are  effectively  undone.  Explicitly 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 pro-
       cesses between sites.  The jobs builtin prints the site on  which  each
       job is executing.

       Under  BS2000,  bs2cmd  executes  commands of the underlying BS2000/OSD
       operating system.

       Under Domain/OS, inlib adds shared libraries to	the  current  environ-
       ment, 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 uni-
       verse.

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

       The VENDOR, OSTYPE and MACHTYPE environment variables indicate  respec-
       tively  the  vendor,  operating system and machine type (microprocessor

       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  vari-
       ables  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 behav-
       ior  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 terminate  sig-
       nals  can be controlled with onintr, and its handling of hangups can be
       controlled with hup and nohup.

       The shell exits on a hangup (see also the logout shell  variable).   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 quoting  literal  charac-
       ters,  and  `execute',  used  when executing commands.  The shell holds
       some settings in each mode constant, 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 modified 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 manipulate and
       debug terminal capabilities from the command line.

       On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win-
       dow  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 available  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++|--
	       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  substi-
	       tuted.	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 description 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 bindings.
	       -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 written  ^charac-
		   ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char-
		   acter written M-character (e.g.,  `M-A'),  a  function  key
		   written  F-string (e.g., `F-string'), or an extended prefix
		   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 com-
		   pletely.
	       -c  command  is	interpreted  as  a builtin or external command
		   instead of an editor command.

	       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  com-
	       mand.

	       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 written `^?'  (caret-question mark).  key and command
	       can  contain backslashed escape sequences (in the style of Sys-
	       tem 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 num-
			   ber nnn

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

       bs2cmd bs2000-command (+)
	       Passes bs2000-command to the  BS2000  command  interpreter  for
	       execution.  Only  non-interactive commands can be executed, and
	       it is not possible to execute any command  that	would  overlay
	       the image of the current process, like /EXECUTE or /CALL-PROCE-
	       DURE. (BS2000 only)

       break   Causes execution to resume after the end of the nearest enclos-
	       ing  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 cur-
	       rent 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

       chdir   A synonym for the cd builtin command.

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

	       command may be a full command name or a glob-pattern (see File-
	       name  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 following:

		   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  cur-
		       rent 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 vari-
		       ables, which must include the current word.

	       list, the list of possible completions, may be one of the  fol-
	       lowing:

		   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 supplied path pre-
			   fix
		   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  sup-
			   plied path prefix
		   v	   Any variables
		   u	   Usernames
		   x	   Like  n,  but  prints  select  when list-choices is
			   used.
		   X	   Completions
	       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 delimiter 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 completing 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 position 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 following `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 directory 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 examples below,
	       could just as well have used 'c/*' or 'n/*' as 'p/*'.

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

		   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  argu-
	       ments,  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 completion were specified first it would always match
	       and the positional completion would never be executed.  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'  completion.   Of
	       course,	one  could still type excluded names manually or over-
	       ride the completion mechanism using  the  complete-word-raw  or
	       list-choices-raw editor 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 particu-
	       lar 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 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  follow-
	       ing  `-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,
	       sequences  of  the  BSD	and/or	System V versions of echo; see
	       echo(1).

       echotc [-sv] arg ... (+)
	       Exercises the terminal capabilities (see termcap(5))  in  args.
	       For  example,  'echotc home' sends the cursor to the home posi-
	       tion, '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 terminals, 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 cor-
	       rectly.	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, messages 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  executes  the
	       resulting command(s) in the context of the current shell.  This
	       is usually used to execute commands generated as the result  of
	       command or variable substitution, because parsing occurs before
	       these substitutions.  See tset(1) 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 specified expr (an
	       expression,  as	described under Expressions) 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.

       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 command 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 output.  Useful for pro-
	       grams 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  pos-
	       sible,  searches for a line of the form `label:', possibly pre-
	       ceded 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 commands (and avoiding exec's).
	       An  exec  is attempted for each component of the path where the
	       hash function 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,  timestamps 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 existing 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
	       ~/.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 history 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  han-
	       dling and the nohup builtin command.

       if (expr) command
	       If  expr (an expression, as described under Expressions) evalu-
	       ates 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 executed, etc.  Any  number  of  else-if
	       pairs are possible; 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 systems, prints the site  on
	       which each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The  first  and second forms sends the specified signal (or, if
	       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 speci-
	       fied resource.  If no maximum-use is given,  then  the  current
	       limit is printed; if no resource is given, then all limitations
	       are given.  If the -h flag is given, the hard limits  are  used
	       instead	of the current limits.	The hard limits impose a ceil-
	       ing 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 supported  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 process

	       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) num-
	       ber 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
	       cated  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 compati-
	       bility 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 identifies 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 com-
	       bination  (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 depend-
	       ing on the filetype or extension.  See the color tcsh  variable
	       and the LS_COLORS environment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
	       The  first  form migrates the process or job to the site speci-
	       fied 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)

	       gets.  The super-user may specify negative  priority  by  using
	       `nice -number ...'.  Command is always executed 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 sig-
	       nals.  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 builtin command.

       notify [%job ...]
	       Causes the shell to notify the  user  asynchronously  when  the
	       status of any of the specified jobs (or, without %job, the cur-
	       rent 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  argu-
	       ments,  restores the default action of the shell on interrupts,
	       which is to terminate shell scripts or to return to the	termi-
	       nal 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 termi-
	       nates because it was interrupted.

	       onintr is ignored if the shell is running detached and in  sys-
	       tem  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 variable can be set to
	       prevent this and the -p flag can be given to override  pushdsi-
	       lent.   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	variables  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 direc-
	       tory 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 direc-
	       tory (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  ele-
	       ment  of  the  directory stack around to be the top element and
	       on dirs.  (+)

       rehash  Causes the internal hash table of the contents of the  directo-
	       ries  in the path variable to be recomputed.  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 directories.  Also
	       flushes the cache of home directories built by tilde expansion.

       repeat count command
	       The  specified  command,  which is subject to the same restric-
	       tions 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	inter-
	       preted 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 format.  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 com-
	       mand 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,  nor-
	       mal  operation of an already-running command will not be inter-
	       rupted so that a scheduled-event list element may be run.

       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  command.   Note,  however,
	       that  variable  expansion  happens 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 cannot
	       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 environ-
	       ment 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 capability cap (as
	       defined in termcap(5)) has the value value.  No sanity checking
	       is  done.   Concept terminal 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 `execute' set of tty modes respectively;
	       without -d, -q or -x, `execute' is used.

	       Without	other  arguments,  setty lists the modes in the chosen

       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
	       descriptors.   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 executed, much like `history -L'.

       stop %job|pid ...
	       Stops the specified jobs or processes which  are  executing  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(1).

       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 execution
	       begins after the  default  label.   Each  case  label  and  the
	       default label must appear at the beginning of a line.  The com-
	       mand 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 termcap(5)).

       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 summary as described under the time variable.  If
	       necessary,  an extra shell is created to print the time statis-
	       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  noth-
	       ing 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 speci-
	       fied,  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.).	Avail-
	       able only if the shell was so compiled; see the	version  shell
	       variable.

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

       which command (+)
       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 fore-
	       ach.

   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 system 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 various calling conventions (e.g., the
	       customary Unix `-h'), except by using a table of many commands.

       periodic
	       Runs  every  tperiod minutes.  This provides a convenient means
	       like precmd.

       precmd  Runs  just  before each prompt is printed.  For example, if one
	       does

		   > alias precmd date

	       then date(1) runs just before the shell prompts for  each  com-
	       mand.  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 environ-
       ment  variable  changes the shell changes the corresponding shell vari-
       able 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 automatically intercon-
       verts 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 authentication.

       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, 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  inactivity	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 vari-
	       able logout to `automatic' and exits.  When the shell automati-
	       cally locks, the user is required to enter his password to con-
	       tinue 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 subdirecto-
	       ries 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.  Alternatively, it  can  be  set  to
	       only ls-F or only ls to enable color to only one command.  Set-
	       ting 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)  consid-
	       ers  periods,  hyphens and underscores (`.', `-' and `_') to be
	       word separators and hyphens and underscores to  be  equivalent.
	       If set to `igncase', the completion becomes case insensitive.

       continue (+)
	       If  set	to  a  list  of  commands, the shell will continue 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>

       dextract (+)
	       If  set,  `pushd +n' extracts the nth directory from the direc-
	       tory 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.
	       `$dirstack[1]' is the current working directory, `$dirstack[2]'
	       the  first  directory on the stack, etc.  Note that the current
	       working directory is `$dirstack[1]' but `=0' in directory stack
	       substitutions,  etc.   One  can change the stack arbitrarily 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 char-
	       acters  corresponds  (from  left  to  right) to the ASCII codes
	       0x00, 0x01, ... 0xff.  Each character 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 character.  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.
	       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 commands all expansions  occur
	       before echoing.	Builtin commands are echoed before command and
	       filename substitution, 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	appro-
	       priate 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 directories with an ellipsis
	       (`...')	instead of `/<skipped>'.

       fignore (+)
	       Lists file name suffixes to be ignored by completion.

       filec   In tcsh, completion is always used and this variable is ignored
	       by  default. If edit is unset, then the traditional csh comple-
	       tion 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  sub-
	       stitution  (q.v.).  The first character of its value is used as
	       the history substitution character, replacing the default char-
	       acter  `!'.   The  second  character  of its value replaces the
	       character `^' in quick substitutions.

       histdup (+)
	       Controls handling of duplicate entries in the history list.  If
	       set to `all' only unique history events are entered in the his-
	       tory list.  If set to `prev' and the last history event is  the
	       same  as  the  current command, then the current command is not
	       file  is  useful  when  sharing the same home directory between
	       different machines, or when saving separate histories  on  dif-
	       ferent  terminals.   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 (+) indicates the format in which his-
	       tory  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 variable.

       ignoreeof
	       If set to the empty string or `0' and the  input  device  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.   Historically  this
	       setting	exited	after  26  successive  EOF's to avoid infinite
	       loops.  If set to a number n, the shell ignores n - 1  consecu-
	       tive  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 executing 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.   Strings
	       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  com-
	       mand will list without asking first.

       listmaxrows (+)
	       The maximum number of rows of items which the list-choices edi-
	       tor 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, `auto-
	       matic' before an automatic logout, and `hangup'	if  the  shell
	       was  killed by a hangup signal (see Signal handling).  See also
	       the autologout shell variable.

       mail    The names of the files or directories  to  check  for  incoming
	       mail,  separated  by  whitespace,  and optionally 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 appropriate.  This functionality is provided  primar-
	       ily  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.
	       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 redirection to insure
	       that files are not accidentally destroyed and that  `>>'  redi-
	       rections   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  existing  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 directo-
	       ries; 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 asynchronously.
	       The default is to present job completions 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 executable 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 some-
	       thing  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 vari-
	       able.  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  com-
	       the terminal.  prompt may include any of the following  format-
	       ting  sequences	(+),  which are replaced by the given informa-
	       tion:

	       %/  The current working directory.
	       %~  The current working directory, but with one's  home	direc-
		   tory  represented  by `~' and other users' home directories
		   represented	by  `~user'  as  per  Filename	 substitution.
		   `~user'  substitution 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 format, 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 vari-
		   able) for normal users, `#' (or  the  second  character  of
		   promptchars) for the superuser.
		   rected 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 noding  is  not
	       set,  then print `DING!' on the change of hour (i.e, `:00' min-
	       utes) 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 format 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  `%#'  formatting
	       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 executed.

       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 automatically disappear and reappear as	necessary,  to
	       ensure  that command input isn't obscured, and will appear only

       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 existing 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  execute  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  terminated
	       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  compro-
	       mise  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

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

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

		   > cd /tmp/to/dst; echo $cwd
		   /tmp/to/dst
		   > cd ..; echo $cwd
		   /tmp/to
		   > cd /tmp/to/dst; 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 auto-
	       matically  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.
	       %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 systems 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 avail-
	       able, 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 spe-
	       cial 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 version number
	       (see tcsh), origin, release date, vendor, 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/csh.login before instead of after
		   /etc/csh.cshrc  and	~/.login  before  instead   of	 after
	       kan Kanji is used if appropriate according to locale  settings,
		   unless the nokanji shell variable is set
	       sm  The system's malloc(3) is used
	       hb  The	`#!<program>  <args>' convention is emulated when exe-
		   cuting shell scripts
	       ng  The newgrp builtin is available
	       rh  The shell attempts to set the REMOTEHOST environment  vari-
		   able
	       afs The	shell  verifies your password with the kerberos server
		   if local authentication fails.  The afsuser shell  variable
		   or  the  AFSUSER  environment  variable override your local
		   username if set.

	       An administrator may enter additional strings to indicate  dif-
	       ferences in the local version.

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

       watch (+)
	       A list of user/terminal pairs to watch for logins and  logouts.
	       If  either  the user is `any' all terminals 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

ENVIRONMENT

       AFSUSER (+)
	       Equivalent to the afsuser shell variable.

       COLUMNS The  number  of	columns in the terminal.  See Terminal manage-
	       ment.

       DISPLAY Used by X Window System (see X(1)).  If set, the shell does not
	       set autologout (q.v.).

       EDITOR  The pathname to a default editor.  See also the VISUAL environ-
	       ment 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(2) system call.

       HOSTTYPE (+)
	       Initialized  to	the type of machine on which the shell is run-
	       ning, 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 documentation.

       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)
	       File  names  can also be colorized based on filename extension.
	       This is specified in the LS_COLORS variable  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  ^-notation.	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 general.  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	generally  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 numeri-
	       cal codes for your standard fore- and background colors.

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

	       cutables.  Equivalent to the path shell variable, but in a dif-
	       ferent format.

       PWD (+) Equivalent to the cwd shell variable, but not  synchronized  to
	       it; updated only after an actual directory change.

       REMOTEHOST (+)
	       The host from which the user has logged in remotely, if this is
	       the case and the shell is able to determine 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  com-
	       mand.

FILES

       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix 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	2.x  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 2.x uses /etc/.login and A/UX,
		       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its equiva-
		       lent.
       ~/.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 ver-
		       sion 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

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

NEW FEATURES (+)

       This manual describes tcsh as a single entity, but  experienced	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 builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

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

       An enhanced history mechanism.  Events in the history  list  are  time-
       stamped.   See  also the history command and its associated shell vari-
       ables, the previously undocumented `#' event specifier  and  new  modi-
       fiers  under  History substitution, 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 associated shell variables, the
       description of Directory stack substitution, the dirstack, owd and sym-
       links shell variables and the normalize-command and normalize-path edi-
       tor commands.

       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 lock-
       ing, command timing and watching for logins and logouts.

       Support for the Native Language System (see Native Language System sup-
       port),  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
       internally.

       Shell   builtin	 functions  are  not  stoppable/restartable.   Command
       sequences of the form `a ; b ; c' are also not handled gracefully  when
       stopping is attempted.  If you suspend `b', the shell will then immedi-
       ately execute `c'.  This is especially  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 primitive;  per-
       haps  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 control.

       Alias substitution is most often used to clumsily simulate shell proce-
       dures; 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 recognized as built-in
       commands.  This would allow control commands 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 `subscribe 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-implementa-
       tion.  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 cre-
       ated the OS to go with it.  It was extremely successful in academia.

       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  substitu-
       tions on a single line to 20.

SEE ALSO

       csh(1),	emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
       tset(1),  vi(1),  x(1),	access(2),  execve(2),	 fork(2),   killpg(2),
       pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
       malloc(3),  setlocale(3),  tty(4),  a.out(5),  termcap(5),  environ(7),
       termio(7), Introduction to the C Shell

VERSION

       This manual documents tcsh 6.13.00 (Astron) 2004-05-19.

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, modifications 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
       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
	 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 version

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

Astron 6.13.00			  19 May 2004			       TCSH(1)

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