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TCSH(1)			    General Commands Manual		       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),  program-
       mable word completion (see Completion and listing), spelling correction
       (see Spelling correction), a history mechanism (see  History  substitu-
       tion),  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 lo-
       gin  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 does not load any resource	or startup files,  or  perform
	   any command hashing,	and thus starts	faster.

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

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

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

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

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

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

       -s  Command input is taken from the standard input.

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

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

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

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

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

       --help
	   Print a help	message	on the standard	output and exit. (+)

       --version
	   Print the version/platform/compilation options on the standard out-
	   put and exit.  This information is also contained  in  the  version
	   shell variable. (+)

       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	~/.tc-
       shrc is not found, ~/.cshrc, then ~/.history (or	the value of the hist-
       file 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 be-
       fore  instead of	after ~/.tcshrc	or ~/.cshrc and	~/.history, if so com-
       piled; 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  lo-
       gin, usually go in one's	~/.login file.	Users who need to use the same
       set of files with both csh(1) and tcsh can have only a  ~/.cshrc	 which
       checks for the existence	of the tcsh shell variable (q.v.) before using
       tcsh-specific commands, or can have both	a  ~/.cshrc  and  a  ~/.tcshrc
       which  sources  (see  the  builtin command) ~/.cshrc.  The rest of this
       manual uses `~/.tcshrc' to mean `~/.tcshrc  or,	if  ~/.tcshrc  is  not
       found, ~/.cshrc'.

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

       One can log out by typing `^D' on an empty line,	`logout' or `login' or
       via  the	 shell's  autologout mechanism (see the	autologout shell 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 lo-
       gout 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
       space  to the end of other completed words, to speed typing and provide
       a visual	indicator of successful	completion.  The addsuffix shell vari-
       able  can  be  unset  to	 prevent this.)	 If no match is	found (perhaps
       `/usr/lost+found' doesn't exist), the terminal bell rings.  If the word
       is  already complete (perhaps there is a	`/usr/lost' on your system, or
       perhaps you were	thinking too far ahead and typed the  whole  thing)  a
       `/' or space is added to	the end	if it isn't already there.

       Completion  works  anywhere in the line,	not at just the	end; completed
       text pushes the rest of the line	to the right.  Completion in the  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  ex-
       ample,  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-
       variables editor	command.

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

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

       The  shell  variable fignore can	be set to a list of suffixes to	be ig-
       nored 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), be-
       cause  they  end	in suffixes in fignore.	 Note that a `\' was needed in
       front of	`~' to prevent it from being expanded to home as described un-
       der  Filename  substitution.  fignore is	ignored	if only	one completion
       is possible.

       If the complete shell variable is set to	`enhance', completion  1)  ig-
       nores  case and 2) considers periods, hyphens and underscores (`.', `-'
       and `_')	to be word separators and hyphens and underscores to be	equiv-
       alent.  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 un-
       derscores  are equivalent.  Periods, however, are not equivalent	to hy-
       phens or	underscores.

       If the complete shell variable is set to	`Enhance', completion  ignores
       case  and differences between a hyphen and an underscore	word separator
       only when the user types	a lowercase character or a  hyphen.   Entering
       an  uppercase character or an underscore	will not match the correspond-
       ing  lowercase  character  or  hyphen  word  separator.	  Typing   `rm
       a--file[^D]'  in	the directory of the previous example would still list
       all  three  files,  but	typing	 `rm   A--file'	  would	  match	  only
       `A_silly_file'	and   typing   `rm   a__file[^D]'   would  match  just
       `A_silly_file' and `another_silly_file'	because	 the  user  explicitly
       used an uppercase or an underscore character.

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

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

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

	   > rm	foo[tab]
	   > rm	foo

       the completion completes	on `foo', even though `food' and `foonly' also
       match.	autoexpand can be set to run the expand-history	editor command
       before each completion attempt, autocorrect can be set to spelling-cor-
       rect  the  word	to  be completed (see Spelling correction) before each
       completion attempt and correct can be set to complete commands automat-
       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  in-
       tends,  and is provided mostly as an experimental feature.  Suggestions
       and improvements	are welcome.

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

       The  character  or characters to	which each command is bound by default
       is given	in parentheses.	 `^character' means a  control	character  and
       `M-character'  a	meta character,	typed as escape-character on terminals
       without a meta key.  Case counts, but commands that are bound  to  let-
       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
	       ignoreeof  shell	 variable  (q.v.) is set to prevent this.  See
	       also delete-char-or-list-or-eof.

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

       expand-glob (^X-*)
	       Expands the glob-pattern	to the left of the cursor.  See	 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 be-
	       ginning with the	current	contents of the	input buffer up	to the
	       cursor  and copies it into the input buffer.  The search	string
	       may be a	glob-pattern (see  Filename  substitution)  containing
	       `*',  `?', `[]' or `{}'.	 up-history and	down-history will pro-
	       ceed 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 ap-
			   propriate.
		   ^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-_)
	       Inserts	the  last  word	of the previous	input line (`!$') into
	       the input buffer.  See also copy-prev-word.

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

       list-choices-raw	(^X-^D)
	       Like list-choices, but ignores user-defined 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,  re-
	       places  it with the full	path to	the executable.	 Special char-
	       acters are quoted.  Aliases are expanded	and  quoted  but  com-
	       mands within aliases are	not.  This command is useful with com-
	       mands 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 de-
	       signed for short	help files.  If	the special alias  helpcommand
	       is defined, it is run with the command name as a	sole argument.
	       Else, documentation should be in	 a  file  named	 command.help,
	       command.1,  command.6, command.8	or command, which should be in
	       one of the directories listed in	the  HPATH  environment	 vari-
	       able.   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'
	       or  `overwrite' to put the editor in that mode at the beginning
	       of each line.  See also overwrite-mode.

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

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

       spell-word (M-s,	M-S)
	       Attempts	 to  correct  the  spelling of the current word	as de-
	       scribed 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 buf-
	       fer.  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, re-
	       places the yanked string	with the next previous string from the
	       killring. This also has the effect of  rotating	the  killring,
	       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.

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

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

       Furthermore,  all Substitutions (see below) except History substitution
       can be prevented	by enclosing the strings  (or  parts  of  strings)  in
       which  they appear with single quotes or	by quoting the crucial 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
       variables can be	set to store the history list automatically on	logout
       and restore it on login.

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

       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 be-
       low).  `!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 be-
       ginning with `vdoc', and, in this example, not find one,	but  `!{v}doc'
       would expand unambiguously to `vi wumpus.mandoc'.  Even in braces, his-
       tory 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 ex-
       pand `!3d' as in	csh(1) say `!{3}d'.

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

	   0	   The first (command) word
	   n	   The nth argument
	   ^	   The first argument, equivalent to `1'
	   $	   The last argument
	   %	   The word matched by an ?s? search
	   x-y	   A range of words
	   -y	   Equivalent to `0-y'
	   *	   Equivalent to `^-$',	but returns nothing if the event  con-
		   tains only 1	word
	   x*	   Equivalent to `x-$'
	   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 ar-
       guments 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 search	 or  event  number  in
		   event specification is used.	 The trailing delimiter	may be
		   omitted if it is immediately	followed by a newline.
	   &	   Repeat the previous substitution.
	   g	   Apply the following modifier	once to	each word.
	   a (+)   Apply the following modifier	as many	times as possible to a
		   single  word.   `a' and `g' can be used together to apply a
		   modifier globally.  With the	`s' modifier,  only  the  pat-
		   terns  contained  in	the original word are substituted, not
		   patterns that contain any substitution result.
	   p	   Print the new command line but do not execute it.
	   q	   Quote the substituted words,	preventing  further  substitu-
		   tions.
	   x	   Like	q, but break into words	at blanks, tabs	and newlines.

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

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

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

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

   Variable substitution
       The shell maintains a list of variables,	each of	which has as  value  a
       list  of	zero or	more words.  The values	of shell variables can be 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  in-
       stance, 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 oc-
       curs.  Strings quoted by	``' are	interpreted later (see Command substi-
       tution  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  en-
       tire  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 be-
       come 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-
       stitution.

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

       $name
       ${name} Substitutes the words of	the value of variable name, each sepa-
	       rated by	a blank.  Braces insulate name from following  charac-
	       ters which would	otherwise be part of it.  Shell	variables have
	       names consisting	of 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 some of 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 se-
	       lector `*' 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 in-
	       terpretation  thereafter.  It can be used to read from the key-
	       board 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 in-
	       terrupt	to interrupt the sequence into which the line is to be
	       substituted, but	csh does not allow this.

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

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

   Command substitution
       Command substitution is indicated by a command enclosed	in  ``'.   The
       output  from  such  a  command is broken	into separate words at blanks,
       tabs and	newlines, and null words are 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.

       By  default, the	shell since version 6.12 replaces all newline and car-
       riage return characters in the command by spaces.  If this is  switched
       off by unsetting	csubstnonl, newlines separate commands as usual.

   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  (unless  either  globdot  or  globstar or both are
       set(+)).	 The character `*' matches any string of characters, including
       the  null string.  The character	`?' matches any	single character.  The
       sequence	`[...]'	matches	any one	of the	characters  enclosed.	Within
       `[...]',	 a  pair  of characters	separated by `-' matches any character
       lexically between the two.

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

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

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

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

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

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

       The globstar shell variable can be set to allow `**' or `***' as	a file
       glob  pattern  that matches any string of characters including `/', re-
       cursively traversing any	existing sub-directories.   For	 example,  `ls
       **.c'  will  list  all  the .c files in the current directory tree.  If
       used by itself, it will match match zero	or more	sub-directories	 (e.g.
       `ls  /usr/include/**/time.h'  will  list	any file named `time.h'	in the
       /usr/include directory tree; `ls	/usr/include/**time.h' will match  any
       file  in	 the  /usr/include  directory tree ending in `time.h'; and `ls
       /usr/include/**time**.h'	will match any .h file with `time' either in a
       subdirectory name or in the filename itself).  To prevent problems with
       recursion, the `**' glob-pattern	will not descend into a	symbolic  link
       containing a directory.	To override this, use `***' (+)

       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  di-
       rectory	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.  Fi-
       nally, cd and pushd interpret `-' as the	old working directory (equiva-
       lent  to	 the  shell variable owd).  This is not	a substitution at all,
       but an abbreviation recognized by only those commands.  Nonetheless, it
       too can be prevented by quoting.

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

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

       Simple  commands	 and  pipelines	may be joined into sequences with `;',
       and will	be executed sequentially.  Commands and	pipelines can also  be
       joined  into  sequences with `||' or `&&', indicating, as in the	C 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 of-
       ten 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  the shell	is not given a -f 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. This hash-
       ing mechanism is	not used:

       1.  If hashing is turned	explicitly off via unhash.

       2.  If the shell	was given a -f argument.

       3.  For each directory component	of path	which does not	begin  with  a
	   `/'.

       4.  If the command contains a `/'.

       In  the	above  four cases the shell concatenates each component	of the
       path vector with	the given command name to form a path name of  a  file
       which  it  then attempts	to execute it. If execution is successful, the
       search stops.

       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:

       < name  Open  file  name	(which is first	variable, command and filename
	       expanded) as the	standard input.
       << word Read the	shell input up to a line which is identical  to	 word.
	       word  is	not subjected to variable, filename or command substi-
	       tution, and each	input line is compared to word before any sub-
	       stitutions  are done on this input line.	 Unless	a quoting `\',
	       `"', `' or ``' appears in word variable and  command  substitu-
	       tion  is	 performed  on	the intervening	lines, allowing	`\' to
	       quote `$', `\' and ``'.	Commands which	are  substituted  have
	       all  blanks, tabs, and newlines preserved, except for the final
	       newline which is	dropped.  The resultant	text is	placed	in  an
	       anonymous temporary file	which is given to the command as 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 ex-
	       panded 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 in-
       put 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
       but useful ways)	from terminal input.  These commands  all  operate  by
       forcing the shell to reread or skip in its input	and, due to the	imple-
       mentation, restrict the placement of some of the	commands.

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

       If the shell's input is not seekable, the shell buffers up input	 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 `%'  be-
       ing,  in	groups,	at the same level.  The	`==' `!=' `=~' and `!~'	opera-
       tors compare their arguments as strings;	all others operate on numbers.
       The  operators  `=~'  and  `!~'	are like `!=' and `==' except that the
       right hand side is a glob-pattern (see Filename	substitution)  against
       which  the left hand operand is matched.	 This reduces the need for use
       of the switch builtin command in	shell scripts when all that is	really
       needed is pattern matching.

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

   Command exit	status
       Commands	can be executed	in expressions and their exit status  returned
       by enclosing them in braces (`{}').  Remember that the braces should be
       separated from the words	of the command by spaces.  Command  executions
       succeed,	returning true,	i.e., `1', if the command exits	with status 0,
       otherwise they fail, returning false, i.e., `0'.	 If more detailed 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 (+)
	   f   Plain file
	   d   Directory
	   l   Symbolic	link (+) *
	   b   Block special file (+)
	   c   Character special file (+)
	   p   Named pipe (fifo) (+) *
	   S   Socket special file (+) *
	   u   Set-user-ID bit is set (+)
	   g   Set-group-ID bit	is set (+)
	   k   Sticky bit is set (+)
	   t   file (which must	be a digit) is an open file descriptor	for  a
	       terminal	device (+)
	   R   Has been	migrated (Convex only) (+)
	   L   Applies	subsequent  operators in a multiple-operator test to a
	       symbolic	link rather than to the	file to	which the link	points
	       (+) *

       file  is	command	and filename expanded and then tested to see if	it has
       the specified relationship to the real user.  If	file does not exist or
       is  inaccessible	 or, for the operators indicated by `*', if the	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 op-
       erators	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  un-
		   known
	   Z	   Size, in bytes

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

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

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

   Jobs
       The  shell  associates  a  job with each	pipeline.  It keeps a table of
       current jobs, printed by	the jobs command, and assigns them small 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.

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

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

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

       When using the system's NLS, the	setlocale(3) function is called	to de-
       termine appropriate character code/classification and sorting (e.g.,  a
       'en_CA.UTF-8'  would yield "UTF-8" as a character code).	 This function
       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 vari-
       ables 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  au-
       tomatically  rebound to self-insert-command.  The corresponding binding
       for the escape-char sequence, if	any, is	left alone.  These  characters
       are  not	rebound	if the NOREBIND	environment variable is	set.  This may
       be useful for the simulated NLS or a primitive real NLS	which  assumes
       full ISO	8859-1.	 Otherwise, all	M-char 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 ex-
       plicitly	set the	tty in 8 bit mode through the appropriate stty(1) com-
       mand 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 op-
       erating 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
       class  or  machine model) of the	system on which	the shell thinks it is
       running.	 These are particularly	useful when sharing one's home	direc-
       tory between several types of machines; one can,	for example,

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

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

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

       Note  also  the	newgrp builtin,	the afsuser and	echo_style shell 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 de-
       bug 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++|--
       @ name[index]++|--
	       The first form prints the values	of all shell variables.

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

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

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

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

       alias [name [wordlist]]
	       Without	arguments,  prints all aliases.	 With name, prints the
	       alias for name.	With name and wordlist,	 assigns  wordlist  as
	       the  alias  of  name.  wordlist is command and filename substi-
	       tuted.  name may	not be `alias' or `unalias'.  See also the un-
	       alias 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 ed-
		   itor.
	       -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 in-
		   stead of an editor command.
	       -s  command is taken as a literal string	and treated as	termi-
		   nal	input  when  key  is typed.  Bound keys	in command are
		   themselves reinterpreted, and this continues	for ten	levels
		   of interpretation.
	       --  Forces  a break from	option processing, so the next word is
		   taken as key	even if	it begins with '-'.
	       -u (or any invalid option)
		   Prints a usage message.

	       key may be a single character or	a string.   If	a  command  is
	       bound  to  a string, the	first character	of the string is bound
	       to sequence-lead-in and the entire string is bound to the  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 ex-
	       ecution.	 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-PROCEDURE.
	       (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] [I--] [name]
	       If a directory name is given, changes the shell's  working  di-
	       rectory	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
	       is  a  shell variable whose value begins	with `/', then this is
	       tried to	see if it is a directory.

	       With -p,	prints the final directory stack, just like dirs.  The
	       -l,  -n and -v flags have the same effect on cd as on dirs, and
	       they imply -p.  (+) Using -- forces a break  from  option  pro-
	       cessing so the next word	is taken as the	directory name even if
	       it begins with '-'. (+)

	       See also	the implicitcd shell variable.

       chdir   A synonym for the cd builtin command.

       complete	[command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
	       Without arguments, lists	all completions.  With 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
		   $var	   Words from the variable var
		   (...)   Words from the given	list
		   `...`   Words from the output of command

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

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

	       command invoked from `...` version has  additional  environment
	       variable	 set,  the  variable name is COMMAND_LINE and contains
	       (as its name indicates) contents	of the current (already	 typed
	       in)  command  line.  One	 can  examine  and use contents	of the
	       COMMAND_LINE variable in	her custom script to  build  more  so-
	       phisticated  completions	(see completion	for svn(1) included in
	       this package).

	       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 di-
	       rectory.	 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,

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

	       or from a command run at	completion time:

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

	       Note  that the complete command does not	itself quote its 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.  Be-
	       cause 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 se-
	       lect argument, and we used `$HOME' instead of `~' because  home
	       directory substitution works at only the	beginning of a word.

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

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

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

	       Finally,	here's a complex example for inspiration:

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

	       This  completes	words  following `-name', `-newer', `-cpio' or
	       `ncpio' (note the pattern which matches both) to	 files,	 words
	       following  `-exec' or `-ok' to commands,	words following	`user'
	       and `group' to users and	groups respectively and	words  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 di-
	       rectory 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.  Be-
	       cause  only  ~/.tcshrc  is  normally sourced before ~/.cshdirs,
	       dirsfile	should be set in ~/.tcshrc rather than ~/.login.

	       The last	form clears the	directory stack.

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

       echotc [-sv] arg	... (+)
	       Exercises the terminal capabilities (see	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 re-
	       sulting	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 0.

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

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

       foreach name (wordlist)
       ...
       end     Successively  sets the variable name to each member of wordlist
	       and executes the	sequence of commands between this command  and
	       the  matching  end.  (Both foreach and end must appear alone on
	       separate	lines.)	 The builtin command continue may be  used  to
	       continue	 the loop prematurely and the builtin 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 the `-n' parameter is not	recognized  and	 words
	       are  delimited  by  null	 characters in the output.  Useful for
	       programs	which wish to use the shell to filename	expand a  list
	       of words.

       goto word
	       word  is	 filename and command-substituted to yield a string of
	       the form	`label'.  The shell rewinds its	input as much as  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 si-
	       multaneous  use.	  Currently  it	 succeeds only when the	shells
	       quit nicely one after another.

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

	       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 re-
	       sponse to hangups, overriding hup.  Without an argument,	causes
	       the  non-interactive shell only to exit on a hangup for the re-
	       mainder of the script.  See also	Signal handling	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  oc-
	       curs  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
	       none is given, the TERM (terminate) signal)  to	the  specified
	       jobs or processes.  job may be a	number,	a string, `', `%', `+'
	       or `-' as described under Jobs.	Signals	are  either  given  by
	       number  or by name (as given in /usr/include/signal.h, stripped
	       of the prefix `SIG').  There is no  default  job;  saying  just
	       `kill'  does not	send a signal to the current job.  If the sig-
	       nal being sent is TERM (terminate) or HUP  (hangup),  then  the
	       job  or	process	is sent	a CONT (continue) signal as well.  The
	       third form lists	the signal names.

       limit [-h] [resource [maximum-use]]
	       Limits the consumption by the current process and each  process
	       it creates to not individually exceed maximum-use on the	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 re-
		      gion

	       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

	       vmemoryuse
		      the  maximum amount of virtual memory a process may have
		      allocated	to it at a given time (address space)

	       vmemoryuse
		      the maximum amount of virtual memory a process may  have
		      allocated	to it at a given time

	       heapsize
		      the  maximum amount of memory a process may allocate per
		      brk() system call

	       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

	       swapsize
		      the maximum amount of swap space reserved	 or  used  for
		      this user

	       maxlocks
		      the maximum number of locks for this user

	       maxsignal
		      the maximum number of pending signals for	this user

	       maxmessage
		      the  maximum  number  of bytes in	POSIX mqueues for this
		      user

	       maxnice
		      the maximum nice priority	the user is allowed  to	 raise
		      mapped from [19...-20] to	[0...39] for this user

	       maxrtprio
		      the  maximum  realtime  priority for this	user maxrttime
		      the timeout for RT tasks in microseconds 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' or	`g' or `gigabytes' may
	       also be used.  For cputime the default  scaling	is  `seconds',
	       while  `m'  for minutes or `h' for hours, or a time of the form
	       `mm:ss' giving minutes and seconds may be used.

	       If maximum-use  is `unlimited',	then  the  limitation  on  the
	       specified  resource  is	removed	(this is equivalent to the un-
	       limit builtin command).

	       For both	resource names and scale factors, unambiguous prefixes
	       of the names suffice.

       log (+) Prints  the watch shell variable	and reports on each user indi-
	       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	shell 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)

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

       nice [+number] [command]
	       Sets the	scheduling priority for	the shell to number, or, with-
	       out  number, to 4.  With	command, runs command at the appropri-
	       ate priority.  The greater the number, the less cpu the process
	       gets.   The  super-user	may specify negative priority by using
	       `nice -number ...'.  Command is always 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,  causes  the
	       non-interactive	shell only 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 la-
	       bel' 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
	       changes	to  it.	  If  dextract is set, however,	`pushd +n' ex-
	       tracts the nth directory, pushes	it onto	the top	of  the	 stack
	       and changes to it.  (+)

	       Finally,	 all  forms  of	pushd 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 pushd as
	       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
	       the  autorehash	shell variable is not set and new commands are
	       added to	directories in path while you are logged in.  With au-
	       torehash,  a new	command	will be	found automatically, except in
	       the special case	where another command of the same  name	 which
	       is  located in a	different directory already exists in the hash
	       table.  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 ex-
	       ecuted  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.

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

       set
       set name	...
       set name=word ...
       set [-r]	[-f|-l]	name=(wordlist)	... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word	... (+)
	       The first form of the command prints the	 value	of  all	 shell
	       variables.   Variables  which  contain  more than a single word
	       print as	a parenthesized	word list.  The	second form sets  name
	       to  the	null  string.	The third form sets name to the	single
	       word.  The fourth form sets  name  to  the  list	 of  words  in
	       wordlist.   In  all cases the value is command and filename ex-
	       panded.	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 sev-
	       enth form makes name read-only, whether or not it has a	value.
	       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
	       set  which are fixed on (`+mode') or off	(`-mode').  The	avail-
	       able modes, and thus the	display, vary from system  to  system.
	       With  -a,  lists	all tty	modes in the chosen set	whether	or not
	       they are	fixed.	With +mode, -mode or mode, fixes  mode	on  or
	       off  or removes control from mode in the	chosen set.  For exam-
	       ple, `setty +echok echoe' fixes `echok' mode on and allows com-
	       mands  to  turn	`echoe'	mode on	or off,	both when the shell is
	       executing commands.

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

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

       source [-h] name	[args ...]
	       The shell reads and executes commands from name.	 The  commands
	       are  not	 placed	 on  the history list.	If any args are	given,
	       they are	placed in argv.	 (+) source commands may be nested; if
	       they  are  nested  too deeply the shell may run out of file de-
	       scriptors.  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 be-
	       gins after the default label.  Each case	label and the  default
	       label  must  appear  at	the  beginning of a line.  The command
	       breaksw causes execution	to continue after the  endsw.	Other-
	       wise 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)).

       termname	[terminal type]	(+)
	       Tests if	terminal type (or the current value of TERM if no ter-
	       minal type is given) has	an entry in the	 hosts	termcap(5)  or
	       terminfo(5)  database.  Prints  the terminal type to stdout and
	       returns 0 if an entry is	present	otherwise returns 1.

       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-
	       tic when	the command completes.	Without	command, prints	a time
	       summary for the current shell and its children.

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

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

       uncomplete pattern (+)
	       Removes all completions whose names match pattern.  `uncomplete
	       *' thus removes all completions.	 It is not an error for	 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 [-hf] [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.
	       Note  that  unlimit may not exit	successful, since most systems
	       do not allow descriptors	to be unlimited.  With -f  errors  are
	       ignored.

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

       while (expr)
       ...
       end     Executes	 the  commands	between	the while and the matching end
	       while expr (an  expression,  as	described  under  Expressions)
	       evaluates  non-zero.   while and	end must appear	alone on their
	       input lines.  break and continue	may be used  to	 terminate  or
	       continue	the loop prematurely.  If the input is a terminal, the
	       user is prompted	the first time through the loop	as with	 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\;\!#:q^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
	       for checking on common but infrequent changes such as new mail.
	       For example, if one does

		   > set tperiod = 30
		   > alias periodic checknews

	       then  the checknews(1) program runs every 30 minutes.  If peri-
	       odic is set but tperiod is unset	or set to 0, periodic  behaves
	       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\;\!#:q^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,	 csubstnonl,  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 group, home, path, shlvl,	term and user with the
       environment variables of	the same names:	whenever the environment vari-
       able changes the	shell changes  the  corresponding  shell  variable  to
       match  (unless  the  shell variable is read-only) and vice versa.  Note
       that although cwd and PWD have identical	meanings, they	are  not  syn-
       chronized  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,	the spell-word editor command is invoked automatically
	       before each completion attempt.

       autoexpand (+)
	       If set, the expand-history editor command is invoked  automati-
	       cally  before  each completion attempt. If this is set to only-
	       history,	then only history will be expanded and a  second  com-
	       pletion will expand filenames.

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

       autologout (+)
	       The  first  word	 is the	number of minutes of 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 lo-
	       gout.  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.

       autorehash (+)
	       If set, the internal hash table of the contents of the directo-
	       ries in the path	variable will be recomputed if	a  command  is
	       not  found  in the hash table.  In addition, the	list of	avail-
	       able commands will be rebuilt for each  command	completion  or
	       spelling	 correction  attempt if	set to `complete' or `correct'
	       respectively; if	set to `always', this will be  done  for  both
	       cases.

       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.).

       compat_expr (+)
	       If set, the shell will evaluate expressions right to left, like
	       the original csh.

       complete	(+)
	       If set to `igncase', the	completion becomes  case  insensitive.
	       If  set to `enhance', completion	ignores	case and considers hy-
	       phens and underscores to	be equivalent; it will also treat  pe-
	       riods, hyphens and underscores (`.', `-'	and `_') as word sepa-
	       rators.	If set to `Enhance', completion	matches	uppercase  and
	       underscore  characters explicitly and matches lowercase and hy-
	       phens in	a case-insensivite manner; it will treat periods,  hy-
	       pens and	underscores as word separators.

       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>

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

       csubstnonl (+)
	       If set, newlines	and carriage returns in	 command  substitution
	       are replaced by spaces.	Set by default.

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

       dextract	(+)
	       If set, `pushd +n' extracts the nth directory from  the	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	(+)
	       Has an effect iff 'dspm'	is listed as part of the version shell
	       variable.  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 '1', 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.

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

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

       dunique (+)
	       If set, pushd removes any instances of name from	the stack  be-
	       fore 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 se-
		       quences;	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 in-
	       teractive shells.

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

       euid (+)
	       The user's effective user ID.

       euser (+)
	       The  first  matching passwd entry name corresponding to the ef-
	       fective user ID.

       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.

       globdot (+)
	       If set, wild-card glob patterns will match files	 and  directo-
	       ries beginning with `.' except for `.' and `..'

       globstar	(+)
	       If  set,	 the  `**' and `***' file glob patterns	will match any
	       string of characters including `/' traversing any existing sub-
	       directories.   (e.g.   `ls  **.c' will list all the .c files in
	       the current directory tree).  If	used by	itself,	it will	 match
	       match   zero   or   more	 sub-directories  (e.g.	 `ls  /usr/in-
	       clude/**/time.h'	will list  any	file  named  `time.h'  in  the
	       /usr/include directory tree; whereas `ls	/usr/include/**time.h'
	       will match any file in the /usr/include directory  tree	ending
	       in  `time.h').	To  prevent  problems with recursion, the `**'
	       glob-pattern will not descend into a symbolic link containing a
	       directory.  To override this, use `***'

       group (+)
	       The user's group	name.

       highlight
	       If  set,	 the incremental search	match (in i-search-back	and i-
	       search-fwd) and the region between the mark and the cursor  are
	       highlighted in reverse video.

	       Highlighting  requires more frequent terminal writes, which in-
	       troduces	extra overhead.	If you	care  about  terminal  perfor-
	       mance, you may want to leave this unset.

       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
	       entered	in  the	history.  If set to `erase' and	the same event
	       is found	in the history list, that old event  gets  erased  and
	       the  current one	gets inserted.	Note that the `prev' and `all'
	       options renumber	history	events so there	are no gaps.

       histfile	(+)
	       The default location in which `history  -S'  and	 `history  -L'
	       look  for a history file.  If unset, ~/.history is used.	 hist-
	       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
	       are put in the killring by  the	editor	commands  that	delete
	       (kill)  strings	of text, e.g. backward-delete-word, kill-line,
	       etc, as well as the copy-region-as-kill command.	 The yank edi-
	       tor  command will yank the most recently	killed string into the
	       command-line, while yank-pop (see Editor	commands) can be  used
	       to yank earlier killed strings.

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

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

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

       listmax (+)
	       The  maximum number of items which the list-choices editor 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    A list of files and directories to check	for incoming mail, op-
	       tionally	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	multi-
	       ple  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 un-
	       less 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.

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

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

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

       noclobber
	       If set, restrictions are	placed on output redirection to	insure
	       that files are not accidentally destroyed and that  `>>'	 redi-
	       rections	 refer	to  existing  files,  as  described in the In-
	       put/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  un-
	       touched 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.

       padhour If set, enable the printing of padding '0' for hours, in	24 and
	       12 hour formats.	 E.G.: 07:45:42	vs. 7:45:42.

       parseoctal
	       To  retain  compatibily	with  older versions numeric variables
	       starting	with 0 are not	interpreted  as	 octal.	 Setting  this
	       variable	enables	proper octal parsing.

       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 de-
	       pending on how it was compiled; see the version shell variable.
	       A  shell	which is given neither the -c nor the -t option	hashes
	       the contents of the directories in path after reading ~/.tcshrc
	       and  each  time	path is	reset.	If one adds a new command to a
	       directory in path while the shell is active, one	may need to do
	       a rehash	for the	shell to find it.

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

       prompt  The string which	is printed before reading  each	 command  from
	       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.
	       %N  The effective 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.
	       %{string%}
		   Includes string as a	literal	escape sequence.  It should be
		   used	only to	change terminal	attributes and should not move
		   the cursor location.	 This cannot be	the last  sequence  in
		   prompt.
	       %?  The	return	code  of  the command executed just before the
		   prompt.
	       %R  In prompt2, the status of the parser.  In prompt3, the cor-
		   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 se-
	       quence in the prompt shell variable is replaced with the	 first
	       character for normal users and the second character for the su-
	       peruser.

       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
	       if  the	prompt,	command	input, and itself will fit together on
	       the first line.	If  edit  isn't	 set,  then  rprompt  will  be
	       printed after the prompt	and before the command input.

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

       savehist
	       If  set,	 the  shell  does `history -S' before exiting.	If the
	       first word is set to a number, at  most	that  many  lines  are
	       saved.  (The number must	be less	than or	equal to history.)  If
	       the second word is set to `merge', the history list  is	merged
	       with  the  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  se-
	       quences	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, unless the variable
	       anyerror	is set,	and any	error in a pipeline or a backquote ex-
	       pansion	will  be propagated (this is the default csh behavior,
	       and the current tcsh default).  If  it  terminated  abnormally,
	       then  0200 is added to the status.  Builtin commands which fail
	       return exit status `1', all other builtin commands return  sta-
	       tus `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 di-
	       rectory 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  di-
	       rectories:

		   > cd	/tmp
		   > mkdir from	from/src to
		   > ln	-s from/src to/dst

	       Here's the behavior with	symlinks unset,

		   > 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.
	       %D  The average amount in (unshared) data/stack space  used  in
		   Kbytes.
	       %K  The total space used	(%X + %D) in Kbytes.
	       %M  The	maximum	 memory	 the process had in use	at any time in
		   Kbytes.
	       %F  The number of major page faults (page needed	to be  brought
		   from	disk).
	       %R  The number of minor page faults.
	       %I  The number of input operations.
	       %O  The number of output	operations.
	       %r  The number of socket	messages received.
	       %s  The number of socket	messages sent.
	       %k  The number of signals received.
	       %w  The number of voluntary context switches (waits).
	       %c  The number of involuntary context switches.

	       Only  the first four sequences are supported on 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 re-
	       source 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  in-
		   creased by the kernel.
	       %d  The	number	of times a process's resident set size was de-
		   creased 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  op-
	       tion.

       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
	       wide  The shell is multibyte encoding clean (like UTF-8)
	       nls   The system's NLS is used; default for systems with	NLS
	       lf    Login shells execute /etc/csh.login before	instead	of af-
		     ter /etc/csh.cshrc	and ~/.login before instead  of	 after
		     ~/.tcshrc and ~/.history.
	       dl    `.' is put	last in	path for security; default
	       nd    `.' is omitted from path for security
	       vi    vi-style editing is the default rather than emacs
	       dtr   Login shells drop DTR when	exiting
	       bye   bye  is a synonym for logout and log is an	alternate name
		     for watchlog
	       al    autologout	is enabled; default
	       kan   Kanji is used if appropriate  according  to  locale  set-
		     tings, 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
		     variable
	       afs   The shell verifies	your password with the kerberos	server
		     if	local authentication fails.  The afsuser  shell	 vari-
		     able  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 lo-
		   gin/logout was from the local host.
	       %m  The hostname	of the remote host up to the first  `.'.   The
		   full	 name is printed if it is an IP	address	or an X	Window
		   System display.

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

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

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 ed-
	       itor 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)
		   or	(none) Orphaned	symbolic link (defaults	to ln)
		   lc	^[[    Left code
		   rc	m      Right code
		   ec	(none) End code	(replaces lc+no+rc)

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

	       File names can also be colorized	based on  filename  extension.
	       This  is	 specified  in the LS_COLORS 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 no-
	       tation,	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.

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

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

       PATH    A colon-separated list of directories in	which to look for exe-
	       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 ED-
	       ITOR environment	variable and the run-fg-editor editor command.

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/lo-
		       gin.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  in-
		       stead  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
		       not have	it either, but tcsh reads /etc/.logout.	 (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or
		       its equivalent.
       /bin/sh	       Used to interpret shell scripts	not  starting  with  a
		       `#'.
       /tmp/sh*	       Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       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
       prompt2 and prompt3).

       Read-only variables.  See Variable substitution.

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

       Shell  builtin  functions  are  not stoppable/restartable.  Command se-
       quences 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 re-
       sults  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 in-
       terface.	 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.

       Control structures should be parsed rather  than	 being	recognized  as
       built-in	commands.  This	would allow control commands to	be placed any-
       where, to be combined with `|', and to be used with `&' and  `;'	 meta-
       syntax.

       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  ex-
       pression	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 in-
       terrupted.

       Command substitution supports multiple commands and conditions, but not
       cycles or backward gotos.

       Report bugs at http://bugs.gw.com/, preferably with fixes.  If you want
       to  help	 maintain  and	test tcsh, send	mail to	tcsh-request@mx.gw.com
       with the	text `subscribe	tcsh' on a line	by itself in the body.

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 op-
       erating systems.	 They built a new pager	for the	DEC PDP-10 and created
       the OS to go with it.  It was extremely successful in academia.

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

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

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

LIMITATIONS
       The system limits argument lists	to ARG_MAX 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  al-
       lowed 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 6.18.01 (Astron) 2012-02-14.

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
	 Ports	 to   HPUX,   SVR2  and	 SVR3,	a  SysV	 version  of  getwd.c,
	 SHORT_STRINGS support and a new version of sh.glob.c
       James J Dempsey,	BBN, and Paul Placeway,	OSU, 1988
	 A/UX port
       Daniel Long, NNSC, 1988
	 wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
	 vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic	Institute, 1989
	 autolist and ambiguous	completion listing
       Alec Wolman, DEC, 1989
	 Newlines in the prompt
       Matt Landau, BBN, 1989
	 ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
	 Magic space bar history expansion
       Mordechai ????, Intel, 1989
	 printprompt() fixes and additions
       Kazuhiro	Honda, Dept. of	Computer Science, Keio University, 1989
	 Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
	 Various bugfixes, improvements	and manual updates
       Hans J. Albertsson (Sun Sweden)
	 ampm, settc and telltc
       Michael Bloom
	 Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
	 Extended key support
       Eric Schnoebelen, Convex, 1990
	 Convex	support, lots of csh bug fixes,	save and restore of  directory
	 stack
       Ron Flax, Apple,	1990
	 A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
	 NLS support and simulated NLS support for non NLS sites, fixes
       Johan Widen, SICS Sweden, 1990
	 shlvl,	Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
	 POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent,	1990-91
	 Vi mode fixes,	expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
	 autolist  beeping  options, modified the history search to search for
	 the whole string from the beginning of	the line to the	cursor.
       Scott Krotz, Motorola, 1991
	 Minix port
       David Dawes, Sydney U. Australia, Physics Dept.,	1991
	 SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
	 Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
	 ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock,	sterling@netcom.com, 1991-1995
	 ETA and Pyramid port, Makefile	and lint fixes,	ignoreeof=n  addition,
	 and various other portability changes and bug fixes
       Jeff Fink, 1992
	 complete-word-fwd and complete-word-back
       Harry C.	Pulley,	1992
	 Coherent port
       Andy Phillips, Mullard Space Science Lab	U.K., 1992
	 VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
	 Walking  process  group fixes,	csh bug	fixes, POSIX file tests, POSIX
	 SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
	 CSOS port
       Kaveh R.	Ghazi, Rutgers University, 1992
	 Tek, m88k, Titan and Masscomp ports and fixes.	 Added	autoconf  sup-
	 port.
       Mark Linderman, Cornell University, 1992
	 OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
	 Linux port
       Tim P. Starrin, NASA Langley Research Center Operations,	1993
	 Read-only variables
       Dave Schweisguth, Yale University, 1993-4
	 New man page and tcsh.man2html
       Larry Schwimmer,	Stanford University, 1993
	 AFS and HESIOD	patches
       Luke Mewburn, RMIT University, 1994-6
	 Enhanced directory printing in	prompt,	added ellipsis and rprompt.
       Edward Hutchins,	Silicon	Graphics Inc., 1996
	 Added implicit	cd.
       Martin Kraemer, 1997
	 Ported	to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
	 Ported	 to  WIN32  (Windows/95	and Windows/NT); wrote all the missing
	 library and message catalog code to interface to Windows.
       Taga Nayuta, 1998
	 Color ls additions.

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

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

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

Astron 6.18.01		       14 February 2012			       TCSH(1)

NAME | SYNOPSIS | DESCRIPTION | REFERENCE | ENVIRONMENT | FILES | NEW FEATURES (+) | BUGS | THE T IN TCSH | LIMITATIONS | SEE ALSO | VERSION | AUTHORS | THANKS TO

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