1TCSH(1) General Commands Manual TCSH(1)
2
6 tcsh - C shell with file name completion and command line editing
7
9 tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
10 tcsh -l
11
13 tcsh is an enhanced but completely compatible version of the Berkeley
14 UNIX C shell, csh(1). It is a command language interpreter usable both
15 as an interactive login shell and a shell script command processor. It
16 includes a command-line editor (see The command-line editor), program‐
17 mable word completion (see Completion and listing), spelling correction
18 (see Spelling correction), a history mechanism (see History substitu‐
19 tion), job control (see Jobs) and a C-like syntax. The NEW FEATURES
20 section describes major enhancements of tcsh over csh(1). Throughout
21 this manual, features of tcsh not found in most csh(1) implementations
22 (specifically, the 4.4BSD csh) are labeled with `(+)', and features
23 which are present in csh(1) but not usually documented are labeled with
24 `(u)'.
25 Argument list processing
27 If the first argument (argument 0) to the shell is `-' then it is a
28 login shell. A login shell can be also specified by invoking the shell
29 with the -l flag as the only argument.
30 The rest of the flag arguments are interpreted as follows:
32 -b Forces a ``break'' from option processing, causing any further
34 shell arguments to be treated as non-option arguments. The remain‐
35 ing arguments will not be interpreted as shell options. This may
36 be used to pass options to a shell script without confusion or pos‐
37 sible subterfuge. The shell will not run a set-user ID script
38 without this option.
39 -c Commands are read from the following argument (which must be
41 present, and must be a single argument), stored in the command
42 shell variable for reference, and executed. Any remaining argu‐
43 ments are placed in the argv shell variable.
44 -d The shell loads the directory stack from ~/.cshdirs as described
46 under Startup and shutdown, whether or not it is a login shell. (+)
47 -Dname[=value]
49 Sets the environment variable name to value. (Domain/OS only) (+)
50 -e The shell exits if any invoked command terminates abnormally or
52 yields a non-zero exit status.
53 -f The shell does not load any resource or startup files, or perform
55 any command hashing, and thus starts faster.
56 -F The shell uses fork(2) instead of vfork(2) to spawn processes. (+)
58 -i The shell is interactive and prompts for its top-level input, even
60 if it appears to not be a terminal. Shells are interactive without
61 this option if their inputs and outputs are terminals.
62 -l The shell is a login shell. Applicable only if -l is the only flag
64 specified.
65 -m The shell loads ~/.tcshrc even if it does not belong to the effec‐
67 tive user. Newer versions of su(1) can pass -m to the shell. (+)
68 -n The shell parses commands but does not execute them. This aids in
70 debugging shell scripts.
71 -q The shell accepts SIGQUIT (see Signal handling) and behaves when it
73 is used under a debugger. Job control is disabled. (u)
74 -s Command input is taken from the standard input.
76 -t The shell reads and executes a single line of input. A `\' may be
78 used to escape the newline at the end of this line and continue
79 onto another line.
80 -v Sets the verbose shell variable, so that command input is echoed
82 after history substitution.
83 -x Sets the echo shell variable, so that commands are echoed immedi‐
85 ately before execution.
86 -V Sets the verbose shell variable even before executing ~/.tcshrc.
88 -X Is to -x as -V is to -v.
90 --help
92 Print a help message on the standard output and exit. (+)
93 --version
95 Print the version/platform/compilation options on the standard out‐
96 put and exit. This information is also contained in the version
97 shell variable. (+)
98 After processing of flag arguments, if arguments remain but none of the
100 -c, -i, -s, or -t options were given, the first argument is taken as
101 the name of a file of commands, or ``script'', to be executed. The
102 shell opens this file and saves its name for possible resubstitution by
103 `$0'. Because many systems use either the standard version 6 or ver‐
104 sion 7 shells whose shell scripts are not compatible with this shell,
105 the shell uses such a `standard' shell to execute a script whose first
106 character is not a `#', i.e., that does not start with a comment.
107 Remaining arguments are placed in the argv shell variable.
109 Startup and shutdown
111 A login shell begins by executing commands from the system files
112 /etc/csh.cshrc and /etc/csh.login. It then executes commands from
113 files in the user's home directory: first ~/.tcshrc (+) or, if
114 ~/.tcshrc is not found, ~/.cshrc, then ~/.history (or the value of the
115 histfile shell variable), then ~/.login, and finally ~/.cshdirs (or the
116 value of the dirsfile shell variable) (+). The shell may read
117 /etc/csh.login before instead of after /etc/csh.cshrc, and ~/.login
118 before instead of after ~/.tcshrc or ~/.cshrc and ~/.history, if so
119 compiled; see the version shell variable. (+)
120 Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on
122 startup.
123 For examples of startup files, please consult http://tcshrc.source‐
125 forge.net.
126 Commands like stty(1) and tset(1), which need be run only once per
128 login, usually go in one's ~/.login file. Users who need to use the
129 same set of files with both csh(1) and tcsh can have only a ~/.cshrc
130 which checks for the existence of the tcsh shell variable (q.v.) before
131 using tcsh-specific commands, or can have both a ~/.cshrc and a
132 ~/.tcshrc which sources (see the builtin command) ~/.cshrc. The rest
133 of this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
134 not found, ~/.cshrc'.
135 In the normal case, the shell begins reading commands from the termi‐
137 nal, prompting with `> '. (Processing of arguments and the use of the
138 shell to process files containing command scripts are described later.)
139 The shell repeatedly reads a line of command input, breaks it into
140 words, places it on the command history list, parses it and executes
141 each command in the line.
142 One can log out by typing `^D' on an empty line, `logout' or `login' or
144 via the shell's autologout mechanism (see the autologout shell vari‐
145 able). When a login shell terminates it sets the logout shell variable
146 to `normal' or `automatic' as appropriate, then executes commands from
147 the files /etc/csh.logout and ~/.logout. The shell may drop DTR on
148 logout if so compiled; see the version shell variable.
149 The names of the system login and logout files vary from system to sys‐
151 tem for compatibility with different csh(1) variants; see FILES.
152 Editing
154 We first describe The command-line editor. The Completion and listing
155 and Spelling correction sections describe two sets of functionality
156 that are implemented as editor commands but which deserve their own
157 treatment. Finally, Editor commands lists and describes the editor
158 commands specific to the shell and their default bindings.
159 The command-line editor (+)
161 Command-line input can be edited using key sequences much like those
162 used in GNU Emacs or vi(1). The editor is active only when the edit
163 shell variable is set, which it is by default in interactive shells.
164 The bindkey builtin can display and change key bindings. Emacs-style
165 key bindings are used by default (unless the shell was compiled other‐
166 wise; see the version shell variable), but bindkey can change the key
167 bindings to vi-style bindings en masse.
168 The shell always binds the arrow keys (as defined in the TERMCAP envi‐
170 ronment variable) to
171 down down-history
173 up up-history
174 left backward-char
175 right forward-char
176 unless doing so would alter another single-character binding. One can
178 set the arrow key escape sequences to the empty string with settc to
179 prevent these bindings. The ANSI/VT100 sequences for arrow keys are
180 always bound.
181 Other key bindings are, for the most part, what Emacs and vi(1) users
183 would expect and can easily be displayed by bindkey, so there is no
184 need to list them here. Likewise, bindkey can list the editor commands
185 with a short description of each.
186 Note that editor commands do not have the same notion of a ``word'' as
188 does the shell. The editor delimits words with any non-alphanumeric
189 characters not in the shell variable wordchars, while the shell recog‐
190 nizes only whitespace and some of the characters with special meanings
191 to it, listed under Lexical structure.
192 Completion and listing (+)
194 The shell is often able to complete words when given a unique abbrevia‐
195 tion. Type part of a word (for example `ls /usr/lost') and hit the tab
196 key to run the complete-word editor command. The shell completes the
197 filename `/usr/lost' to `/usr/lost+found/', replacing the incomplete
198 word with the complete word in the input buffer. (Note the terminal
199 `/'; completion adds a `/' to the end of completed directories and a
200 space to the end of other completed words, to speed typing and provide
201 a visual indicator of successful completion. The addsuffix shell vari‐
202 able can be unset to prevent this.) If no match is found (perhaps
203 `/usr/lost+found' doesn't exist), the terminal bell rings. If the word
204 is already complete (perhaps there is a `/usr/lost' on your system, or
205 perhaps you were thinking too far ahead and typed the whole thing) a
206 `/' or space is added to the end if it isn't already there.
207 Completion works anywhere in the line, not at just the end; completed
209 text pushes the rest of the line to the right. Completion in the mid‐
210 dle of a word often results in leftover characters to the right of the
211 cursor that need to be deleted.
212 Commands and variables can be completed in much the same way. For
214 example, typing `em[tab]' would complete `em' to `emacs' if emacs were
215 the only command on your system beginning with `em'. Completion can
216 find a command in any directory in path or if given a full pathname.
217 Typing `echo $ar[tab]' would complete `$ar' to `$argv' if no other
218 variable began with `ar'.
219 The shell parses the input buffer to determine whether the word you
221 want to complete should be completed as a filename, command or vari‐
222 able. The first word in the buffer and the first word following `;',
223 `|', `|&', `&&' or `||' is considered to be a command. A word begin‐
224 ning with `$' is considered to be a variable. Anything else is a file‐
225 name. An empty line is `completed' as a filename.
226 You can list the possible completions of a word at any time by typing
228 `^D' to run the delete-char-or-list-or-eof editor command. The shell
229 lists the possible completions using the ls-F builtin (q.v.) and re‐
230 prints the prompt and unfinished command line, for example:
231 > ls /usr/l[^D]
233 lbin/ lib/ local/ lost+found/
234 > ls /usr/l
235 If the autolist shell variable is set, the shell lists the remaining
237 choices (if any) whenever completion fails:
238 > set autolist
240 > nm /usr/lib/libt[tab]
241 libtermcap.a@ libtermlib.a@
242 > nm /usr/lib/libterm
243 If autolist is set to `ambiguous', choices are listed only when comple‐
245 tion fails and adds no new characters to the word being completed.
246 A filename to be completed can contain variables, your own or others'
248 home directories abbreviated with `~' (see Filename substitution) and
249 directory stack entries abbreviated with `=' (see Directory stack sub‐
250 stitution). For example,
251 > ls ~k[^D]
253 kahn kas kellogg
254 > ls ~ke[tab]
255 > ls ~kellogg/
256 or
258 > set local = /usr/local
260 > ls $lo[tab]
261 > ls $local/[^D]
262 bin/ etc/ lib/ man/ src/
263 > ls $local/
264 Note that variables can also be expanded explicitly with the expand-
266 variables editor command.
267 delete-char-or-list-or-eof lists at only the end of the line; in the
269 middle of a line it deletes the character under the cursor and on an
270 empty line it logs one out or, if ignoreeof is set, does nothing.
271 `M-^D', bound to the editor command list-choices, lists completion pos‐
272 sibilities anywhere on a line, and list-choices (or any one of the
273 related editor commands that do or don't delete, list and/or log out,
274 listed under delete-char-or-list-or-eof) can be bound to `^D' with the
275 bindkey builtin command if so desired.
276 The complete-word-fwd and complete-word-back editor commands (not bound
278 to any keys by default) can be used to cycle up and down through the
279 list of possible completions, replacing the current word with the next
280 or previous word in the list.
281 The shell variable fignore can be set to a list of suffixes to be
283 ignored by completion. Consider the following:
284 > ls
286 Makefile condiments.h~ main.o side.c
287 README main.c meal side.o
288 condiments.h main.c~
289 > set fignore = (.o \~)
290 > emacs ma[^D]
291 main.c main.c~ main.o
292 > emacs ma[tab]
293 > emacs main.c
294 `main.c~' and `main.o' are ignored by completion (but not listing),
296 because they end in suffixes in fignore. Note that a `\' was needed in
297 front of `~' to prevent it from being expanded to home as described
298 under Filename substitution. fignore is ignored if only one completion
299 is possible.
300 If the complete shell variable is set to `enhance', completion 1)
302 ignores case and 2) considers periods, hyphens and underscores (`.',
303 `-' and `_') to be word separators and hyphens and underscores to be
304 equivalent. If you had the following files
305 comp.lang.c comp.lang.perl comp.std.c++
307 comp.lang.c++ comp.std.c
308 and typed `mail -f c.l.c[tab]', it would be completed to `mail -f
310 comp.lang.c', and ^D would list `comp.lang.c' and `comp.lang.c++'.
311 `mail -f c..c++[^D]' would list `comp.lang.c++' and `comp.std.c++'.
312 Typing `rm a--file[^D]' in the following directory
313 A_silly_file a-hyphenated-file another_silly_file
315 would list all three files, because case is ignored and hyphens and
317 underscores are equivalent. Periods, however, are not equivalent to
318 hyphens or underscores.
319 Completion and listing are affected by several other shell variables:
321 recexact can be set to complete on the shortest possible unique match,
322 even if more typing might result in a longer match:
323 > ls
325 fodder foo food foonly
326 > set recexact
327 > rm fo[tab]
328 just beeps, because `fo' could expand to `fod' or `foo', but if we type
330 another `o',
331 > rm foo[tab]
333 > rm foo
334 the completion completes on `foo', even though `food' and `foonly' also
336 match. autoexpand can be set to run the expand-history editor command
337 before each completion attempt, autocorrect can be set to spelling-cor‐
338 rect the word to be completed (see Spelling correction) before each
339 completion attempt and correct can be set to complete commands automat‐
340 ically after one hits `return'. matchbeep can be set to make comple‐
341 tion beep or not beep in a variety of situations, and nobeep can be set
342 to never beep at all. nostat can be set to a list of directories
343 and/or patterns that match directories to prevent the completion mecha‐
344 nism from stat(2)ing those directories. listmax and listmaxrows can be
345 set to limit the number of items and rows (respectively) that are
346 listed without asking first. recognize_only_executables can be set to
347 make the shell list only executables when listing commands, but it is
348 quite slow.
349 Finally, the complete builtin command can be used to tell the shell how
351 to complete words other than filenames, commands and variables. Com‐
352 pletion and listing do not work on glob-patterns (see Filename substi‐
353 tution), but the list-glob and expand-glob editor commands perform
354 equivalent functions for glob-patterns.
355 Spelling correction (+)
357 The shell can sometimes correct the spelling of filenames, commands and
358 variable names as well as completing and listing them.
359 Individual words can be spelling-corrected with the spell-word editor
361 command (usually bound to M-s and M-S) and the entire input buffer with
362 spell-line (usually bound to M-$). The correct shell variable can be
363 set to `cmd' to correct the command name or `all' to correct the entire
364 line each time return is typed, and autocorrect can be set to correct
365 the word to be completed before each completion attempt.
366 When spelling correction is invoked in any of these ways and the shell
368 thinks that any part of the command line is misspelled, it prompts with
369 the corrected line:
370 > set correct = cmd
372 > lz /usr/bin
373 CORRECT>ls /usr/bin (y|n|e|a)?
374 One can answer `y' or space to execute the corrected line, `e' to leave
376 the uncorrected command in the input buffer, `a' to abort the command
377 as if `^C' had been hit, and anything else to execute the original line
378 unchanged.
379 Spelling correction recognizes user-defined completions (see the com‐
381 plete builtin command). If an input word in a position for which a
382 completion is defined resembles a word in the completion list, spelling
383 correction registers a misspelling and suggests the latter word as a
384 correction. However, if the input word does not match any of the pos‐
385 sible completions for that position, spelling correction does not reg‐
386 ister a misspelling.
387 Like completion, spelling correction works anywhere in the line, push‐
389 ing the rest of the line to the right and possibly leaving extra char‐
390 acters to the right of the cursor.
391 Beware: spelling correction is not guaranteed to work the way one
393 intends, and is provided mostly as an experimental feature. Sugges‐
394 tions and improvements are welcome.
395 Editor commands (+)
397 `bindkey' lists key bindings and `bindkey -l' lists and briefly
398 describes editor commands. Only new or especially interesting editor
399 commands are described here. See emacs(1) and vi(1) for descriptions
400 of each editor's key bindings.
401 The character or characters to which each command is bound by default
403 is given in parentheses. `^character' means a control character and
404 `M-character' a meta character, typed as escape-character on terminals
405 without a meta key. Case counts, but commands that are bound to let‐
406 ters by default are bound to both lower- and uppercase letters for con‐
407 venience.
408 complete-word (tab)
410 Completes a word as described under Completion and listing.
411 complete-word-back (not bound)
413 Like complete-word-fwd, but steps up from the end of the list.
414 complete-word-fwd (not bound)
416 Replaces the current word with the first word in the list of
417 possible completions. May be repeated to step down through the
418 list. At the end of the list, beeps and reverts to the incom‐
419 plete word.
420 complete-word-raw (^X-tab)
422 Like complete-word, but ignores user-defined completions.
423 copy-prev-word (M-^_)
425 Copies the previous word in the current line into the input
426 buffer. See also insert-last-word.
427 dabbrev-expand (M-/)
429 Expands the current word to the most recent preceding one for
430 which the current is a leading substring, wrapping around the
431 history list (once) if necessary. Repeating dabbrev-expand
432 without any intervening typing changes to the next previous
433 word etc., skipping identical matches much like history-search-
434 backward does.
435 delete-char (not bound)
437 Deletes the character under the cursor. See also delete-char-
438 or-list-or-eof.
439 delete-char-or-eof (not bound)
441 Does delete-char if there is a character under the cursor or
442 end-of-file on an empty line. See also delete-char-or-list-or-
443 eof.
444 delete-char-or-list (not bound)
446 Does delete-char if there is a character under the cursor or
447 list-choices at the end of the line. See also delete-char-or-
448 list-or-eof.
449 delete-char-or-list-or-eof (^D)
451 Does delete-char if there is a character under the cursor,
452 list-choices at the end of the line or end-of-file on an empty
453 line. See also those three commands, each of which does only a
454 single action, and delete-char-or-eof, delete-char-or-list and
455 list-or-eof, each of which does a different two out of the
456 three.
457 down-history (down-arrow, ^N)
459 Like up-history, but steps down, stopping at the original input
460 line.
461 end-of-file (not bound)
463 Signals an end of file, causing the shell to exit unless the
464 ignoreeof shell variable (q.v.) is set to prevent this. See
465 also delete-char-or-list-or-eof.
466 expand-history (M-space)
468 Expands history substitutions in the current word. See History
469 substitution. See also magic-space, toggle-literal-history and
470 the autoexpand shell variable.
471 expand-glob (^X-*)
473 Expands the glob-pattern to the left of the cursor. See File‐
474 name substitution.
475 expand-line (not bound)
477 Like expand-history, but expands history substitutions in each
478 word in the input buffer,
479 expand-variables (^X-$)
481 Expands the variable to the left of the cursor. See Variable
482 substitution.
483 history-search-backward (M-p, M-P)
485 Searches backwards through the history list for a command
486 beginning with the current contents of the input buffer up to
487 the cursor and copies it into the input buffer. The search
488 string may be a glob-pattern (see Filename substitution) con‐
489 taining `*', `?', `[]' or `{}'. up-history and down-history
490 will proceed from the appropriate point in the history list.
491 Emacs mode only. See also history-search-forward and i-search-
492 back.
493 history-search-forward (M-n, M-N)
495 Like history-search-backward, but searches forward.
496 i-search-back (not bound)
498 Searches backward like history-search-backward, copies the
499 first match into the input buffer with the cursor positioned at
500 the end of the pattern, and prompts with `bck: ' and the first
501 match. Additional characters may be typed to extend the
502 search, i-search-back may be typed to continue searching with
503 the same pattern, wrapping around the history list if neces‐
504 sary, (i-search-back must be bound to a single character for
505 this to work) or one of the following special characters may be
506 typed:
507 ^W Appends the rest of the word under the cursor to
509 the search pattern.
510 delete (or any character bound to backward-delete-char)
511 Undoes the effect of the last character typed and
512 deletes a character from the search pattern if
513 appropriate.
514 ^G If the previous search was successful, aborts the
515 entire search. If not, goes back to the last suc‐
516 cessful search.
517 escape Ends the search, leaving the current line in the
518 input buffer.
519 Any other character not bound to self-insert-command terminates
521 the search, leaving the current line in the input buffer, and
522 is then interpreted as normal input. In particular, a carriage
523 return causes the current line to be executed. Emacs mode
524 only. See also i-search-fwd and history-search-backward.
525 i-search-fwd (not bound)
527 Like i-search-back, but searches forward.
528 insert-last-word (M-_)
530 Inserts the last word of the previous input line (`!$') into
531 the input buffer. See also copy-prev-word.
532 list-choices (M-^D)
534 Lists completion possibilities as described under Completion
535 and listing. See also delete-char-or-list-or-eof and list-
536 choices-raw.
537 list-choices-raw (^X-^D)
539 Like list-choices, but ignores user-defined completions.
540 list-glob (^X-g, ^X-G)
542 Lists (via the ls-F builtin) matches to the glob-pattern (see
543 Filename substitution) to the left of the cursor.
544 list-or-eof (not bound)
546 Does list-choices or end-of-file on an empty line. See also
547 delete-char-or-list-or-eof.
548 magic-space (not bound)
550 Expands history substitutions in the current line, like expand-
551 history, and inserts a space. magic-space is designed to be
552 bound to the space bar, but is not bound by default.
553 normalize-command (^X-?)
555 Searches for the current word in PATH and, if it is found,
556 replaces it with the full path to the executable. Special
557 characters are quoted. Aliases are expanded and quoted but
558 commands within aliases are not. This command is useful with
559 commands that take commands as arguments, e.g., `dbx' and `sh
560 -x'.
561 normalize-path (^X-n, ^X-N)
563 Expands the current word as described under the `expand' set‐
564 ting of the symlinks shell variable.
565 overwrite-mode (unbound)
567 Toggles between input and overwrite modes.
568 run-fg-editor (M-^Z)
570 Saves the current input line and looks for a stopped job with a
571 name equal to the last component of the file name part of the
572 EDITOR or VISUAL environment variables, or, if neither is set,
573 `ed' or `vi'. If such a job is found, it is restarted as if
574 `fg %job' had been typed. This is used to toggle back and
575 forth between an editor and the shell easily. Some people bind
576 this command to `^Z' so they can do this even more easily.
577 run-help (M-h, M-H)
579 Searches for documentation on the current command, using the
580 same notion of `current command' as the completion routines,
581 and prints it. There is no way to use a pager; run-help is
582 designed for short help files. If the special alias helpcom‐
583 mand is defined, it is run with the command name as a sole
584 argument. Else, documentation should be in a file named com‐
585 mand.help, command.1, command.6, command.8 or command, which
586 should be in one of the directories listed in the HPATH envi‐
587 ronment variable. If there is more than one help file only the
588 first is printed.
589 self-insert-command (text characters)
591 In insert mode (the default), inserts the typed character into
592 the input line after the character under the cursor. In over‐
593 write mode, replaces the character under the cursor with the
594 typed character. The input mode is normally preserved between
595 lines, but the inputmode shell variable can be set to `insert'
596 or `overwrite' to put the editor in that mode at the beginning
597 of each line. See also overwrite-mode.
598 sequence-lead-in (arrow prefix, meta prefix, ^X)
600 Indicates that the following characters are part of a multi-key
601 sequence. Binding a command to a multi-key sequence really
602 creates two bindings: the first character to sequence-lead-in
603 and the whole sequence to the command. All sequences beginning
604 with a character bound to sequence-lead-in are effectively
605 bound to undefined-key unless bound to another command.
606 spell-line (M-$)
608 Attempts to correct the spelling of each word in the input buf‐
609 fer, like spell-word, but ignores words whose first character
610 is one of `-', `!', `^' or `%', or which contain `\', `*' or
611 `?', to avoid problems with switches, substitutions and the
612 like. See Spelling correction.
613 spell-word (M-s, M-S)
615 Attempts to correct the spelling of the current word as
616 described under Spelling correction. Checks each component of
617 a word which appears to be a pathname.
618 toggle-literal-history (M-r, M-R)
620 Expands or `unexpands' history substitutions in the input buf‐
621 fer. See also expand-history and the autoexpand shell vari‐
622 able.
623 undefined-key (any unbound key)
625 Beeps.
626 up-history (up-arrow, ^P)
628 Copies the previous entry in the history list into the input
629 buffer. If histlit is set, uses the literal form of the entry.
630 May be repeated to step up through the history list, stopping
631 at the top.
632 vi-search-back (?)
634 Prompts with `?' for a search string (which may be a glob-pat‐
635 tern, as with history-search-backward), searches for it and
636 copies it into the input buffer. The bell rings if no match is
637 found. Hitting return ends the search and leaves the last
638 match in the input buffer. Hitting escape ends the search and
639 executes the match. vi mode only.
640 vi-search-fwd (/)
642 Like vi-search-back, but searches forward.
643 which-command (M-?)
645 Does a which (see the description of the builtin command) on
646 the first word of the input buffer.
647 yank-pop (M-y)
649 When executed immediately after a yank or another yank-pop,
650 replaces the yanked string with the next previous string from
651 the killring. This also has the effect of rotating the kill‐
652 ring, such that this string will be considered the most
653 recently killed by a later yank command. Repeating yank-pop
654 will cycle through the killring any number of times.
655 Lexical structure
657 The shell splits input lines into words at blanks and tabs. The spe‐
658 cial characters `&', `|', `;', `<', `>', `(', and `)' and the doubled
659 characters `&&', `||', `<<' and `>>' are always separate words, whether
660 or not they are surrounded by whitespace.
661 When the shell's input is not a terminal, the character `#' is taken to
663 begin a comment. Each `#' and the rest of the input line on which it
664 appears is discarded before further parsing.
665 A special character (including a blank or tab) may be prevented from
667 having its special meaning, and possibly made part of another word, by
668 preceding it with a backslash (`\') or enclosing it in single (`''),
669 double (`"') or backward (``') quotes. When not otherwise quoted a
670 newline preceded by a `\' is equivalent to a blank, but inside quotes
671 this sequence results in a newline.
672 Furthermore, all Substitutions (see below) except History substitution
674 can be prevented by enclosing the strings (or parts of strings) in
675 which they appear with single quotes or by quoting the crucial charac‐
676 ter(s) (e.g., `$' or ``' for Variable substitution or Command substitu‐
677 tion respectively) with `\'. (Alias substitution is no exception:
678 quoting in any way any character of a word for which an alias has been
679 defined prevents substitution of the alias. The usual way of quoting
680 an alias is to precede it with a backslash.) History substitution is
681 prevented by backslashes but not by single quotes. Strings quoted with
682 double or backward quotes undergo Variable substitution and Command
683 substitution, but other substitutions are prevented.
684 Text inside single or double quotes becomes a single word (or part of
686 one). Metacharacters in these strings, including blanks and tabs, do
687 not form separate words. Only in one special case (see Command substi‐
688 tution below) can a double-quoted string yield parts of more than one
689 word; single-quoted strings never do. Backward quotes are special:
690 they signal Command substitution (q.v.), which may result in more than
691 one word.
692 Quoting complex strings, particularly strings which themselves contain
694 quoting characters, can be confusing. Remember that quotes need not be
695 used as they are in human writing! It may be easier to quote not an
696 entire string, but only those parts of the string which need quoting,
697 using different types of quoting to do so if appropriate.
698 The backslash_quote shell variable (q.v.) can be set to make back‐
700 slashes always quote `\', `'', and `"'. (+) This may make complex
701 quoting tasks easier, but it can cause syntax errors in csh(1) scripts.
702 Substitutions
704 We now describe the various transformations the shell performs on the
705 input in the order in which they occur. We note in passing the data
706 structures involved and the commands and variables which affect them.
707 Remember that substitutions can be prevented by quoting as described
708 under Lexical structure.
709 History substitution
711 Each command, or ``event'', input from the terminal is saved in the
712 history list. The previous command is always saved, and the history
713 shell variable can be set to a number to save that many commands. The
714 histdup shell variable can be set to not save duplicate events or con‐
715 secutive duplicate events.
716 Saved commands are numbered sequentially from 1 and stamped with the
718 time. It is not usually necessary to use event numbers, but the cur‐
719 rent event number can be made part of the prompt by placing an `!' in
720 the prompt shell variable.
721 The shell actually saves history in expanded and literal (unexpanded)
723 forms. If the histlit shell variable is set, commands that display and
724 store history use the literal form.
725 The history builtin command can print, store in a file, restore and
727 clear the history list at any time, and the savehist and histfile shell
728 variables can be can be set to store the history list automatically on
729 logout and restore it on login.
730 History substitutions introduce words from the history list into the
732 input stream, making it easy to repeat commands, repeat arguments of a
733 previous command in the current command, or fix spelling mistakes in
734 the previous command with little typing and a high degree of confi‐
735 dence.
736 History substitutions begin with the character `!'. They may begin
738 anywhere in the input stream, but they do not nest. The `!' may be
739 preceded by a `\' to prevent its special meaning; for convenience, a
740 `!' is passed unchanged when it is followed by a blank, tab, newline,
741 `=' or `('. History substitutions also occur when an input line begins
742 with `^'. This special abbreviation will be described later. The
743 characters used to signal history substitution (`!' and `^') can be
744 changed by setting the histchars shell variable. Any input line which
745 contains a history substitution is printed before it is executed.
746 A history substitution may have an ``event specification'', which indi‐
748 cates the event from which words are to be taken, a ``word designa‐
749 tor'', which selects particular words from the chosen event, and/or a
750 ``modifier'', which manipulates the selected words.
751 An event specification can be
753 n A number, referring to a particular event
755 -n An offset, referring to the event n before the current
756 event
757 # The current event. This should be used carefully in
758 csh(1), where there is no check for recursion. tcsh allows
759 10 levels of recursion. (+)
760 ! The previous event (equivalent to `-1')
761 s The most recent event whose first word begins with the
762 string s
763 ?s? The most recent event which contains the string s. The
764 second `?' can be omitted if it is immediately followed by
765 a newline.
766 For example, consider this bit of someone's history list:
768 9 8:30 nroff -man wumpus.man
770 10 8:31 cp wumpus.man wumpus.man.old
771 11 8:36 vi wumpus.man
772 12 8:37 diff wumpus.man.old wumpus.man
773 The commands are shown with their event numbers and time stamps. The
775 current event, which we haven't typed in yet, is event 13. `!11' and
776 `!-2' refer to event 11. `!!' refers to the previous event, 12. `!!'
777 can be abbreviated `!' if it is followed by `:' (`:' is described
778 below). `!n' refers to event 9, which begins with `n'. `!?old?' also
779 refers to event 12, which contains `old'. Without word designators or
780 modifiers history references simply expand to the entire event, so we
781 might type `!cp' to redo the copy command or `!!|more' if the `diff'
782 output scrolled off the top of the screen.
783 History references may be insulated from the surrounding text with
785 braces if necessary. For example, `!vdoc' would look for a command
786 beginning with `vdoc', and, in this example, not find one, but
787 `!{v}doc' would expand unambiguously to `vi wumpus.mandoc'. Even in
788 braces, history substitutions do not nest.
789 (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
791 `d' appended to it, tcsh expands it to the last event beginning with
792 `3d'; only completely numeric arguments are treated as event numbers.
793 This makes it possible to recall events beginning with numbers. To
794 expand `!3d' as in csh(1) say `!{3}d'.
795 To select words from an event we can follow the event specification by
797 a `:' and a designator for the desired words. The words of an input
798 line are numbered from 0, the first (usually command) word being 0, the
799 second word (first argument) being 1, etc. The basic word designators
800 are:
801 0 The first (command) word
803 n The nth argument
804 ^ The first argument, equivalent to `1'
805 $ The last argument
806 % The word matched by an ?s? search
807 x-y A range of words
808 -y Equivalent to `0-y'
809 * Equivalent to `^-$', but returns nothing if the event con‐
810 tains only 1 word
811 x* Equivalent to `x-$'
812 x- Equivalent to `x*', but omitting the last word (`$')
813 Selected words are inserted into the command line separated by single
815 blanks. For example, the `diff' command in the previous example might
816 have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
817 argument from the previous event) or `diff !-2:2 !-2:1' to select and
818 swap the arguments from the `cp' command. If we didn't care about the
819 order of the `diff' we might have said `diff !-2:1-2' or simply `diff
820 !-2:*'. The `cp' command might have been written `cp wumpus.man
821 !#:1.old', using `#' to refer to the current event. `!n:- hurkle.man'
822 would reuse the first two words from the `nroff' command to say `nroff
823 -man hurkle.man'.
824 The `:' separating the event specification from the word designator can
826 be omitted if the argument selector begins with a `^', `$', `*', `%' or
827 `-'. For example, our `diff' command might have been `diff !!^.old
828 !!^' or, equivalently, `diff !!$.old !!$'. However, if `!!' is abbre‐
829 viated `!', an argument selector beginning with `-' will be interpreted
830 as an event specification.
831 A history reference may have a word designator but no event specifica‐
833 tion. It then references the previous command. Continuing our `diff'
834 example, we could have said simply `diff !^.old !^' or, to get the
835 arguments in the opposite order, just `diff !*'.
836 The word or words in a history reference can be edited, or ``modi‐
838 fied'', by following it with one or more modifiers, each preceded by a
839 `:':
840 h Remove a trailing pathname component, leaving the head.
842 t Remove all leading pathname components, leaving the tail.
843 r Remove a filename extension `.xxx', leaving the root name.
844 e Remove all but the extension.
845 u Uppercase the first lowercase letter.
846 l Lowercase the first uppercase letter.
847 s/l/r/ Substitute l for r. l is simply a string like r, not a
848 regular expression as in the eponymous ed(1) command. Any
849 character may be used as the delimiter in place of `/'; a
850 `\' can be used to quote the delimiter expect `(', `)', `|'
851 and `>' inside l and r. The character `&' in the r is
852 replaced by l; `\' also quotes `&'. If l is empty (``''),
853 the l from a previous substitution or the s from a previous
854 search or event number in event specification is used. The
855 trailing delimiter may be omitted if it is immediately fol‐
856 lowed by a newline.
857 & Repeat the previous substitution.
858 g Apply the following modifier once to each word.
859 a (+) Apply the following modifier as many times as possible to a
860 single word. `a' and `g' can be used together to apply a
861 modifier globally. With the `s' modifier, only the pat‐
862 terns contained in the original word are substituted, not
863 patterns that contain any substitution result.
864 p Print the new command line but do not execute it.
865 q Quote the substituted words, preventing further substitu‐
866 tions.
867 x Like q, but break into words at blanks, tabs and newlines.
868 Modifiers are applied to only the first modifiable word (unless `g' is
870 used). It is an error for no word to be modifiable.
871 For example, the `diff' command might have been written as `diff wum‐
873 pus.man.old !#^:r', using `:r' to remove `.old' from the first argument
874 on the same line (`!#^'). We could say `echo hello out there', then
875 `echo !*:u' to capitalize `hello', `echo !*:au' to say it out loud, or
876 `echo !*:agu' to really shout. We might follow `mail -s "I forgot my
877 password" rot' with `!:s/rot/root' to correct the spelling of `root'
878 (but see Spelling correction for a different approach).
879 There is a special abbreviation for substitutions. `^', when it is the
881 first character on an input line, is equivalent to `!:s^'. Thus we
882 might have said `^rot^root' to make the spelling correction in the pre‐
883 vious example. This is the only history substitution which does not
884 explicitly begin with `!'.
885 (+) In csh as such, only one modifier may be applied to each history or
887 variable expansion. In tcsh, more than one may be used, for example
888 % mv wumpus.man /usr/man/man1/wumpus.1
890 % man !$:t:r
891 man wumpus
892 In csh, the result would be `wumpus.1:r'. A substitution followed by a
894 colon may need to be insulated from it with braces:
895 > mv a.out /usr/games/wumpus
897 > setenv PATH !$:h:$PATH
898 Bad ! modifier: $.
899 > setenv PATH !{-2$:h}:$PATH
900 setenv PATH /usr/games:/bin:/usr/bin:.
901 The first attempt would succeed in csh but fails in tcsh, because tcsh
903 expects another modifier after the second colon rather than `$'.
904 Finally, history can be accessed through the editor as well as through
906 the substitutions just described. The up- and down-history, history-
907 search-backward and -forward, i-search-back and -fwd, vi-search-back
908 and -fwd, copy-prev-word and insert-last-word editor commands search
909 for events in the history list and copy them into the input buffer.
910 The toggle-literal-history editor command switches between the expanded
911 and literal forms of history lines in the input buffer. expand-history
912 and expand-line expand history substitutions in the current word and in
913 the entire input buffer respectively.
914 Alias substitution
916 The shell maintains a list of aliases which can be set, unset and
917 printed by the alias and unalias commands. After a command line is
918 parsed into simple commands (see Commands) the first word of each com‐
919 mand, left-to-right, is checked to see if it has an alias. If so, the
920 first word is replaced by the alias. If the alias contains a history
921 reference, it undergoes History substitution (q.v.) as though the orig‐
922 inal command were the previous input line. If the alias does not con‐
923 tain a history reference, the argument list is left untouched.
924 Thus if the alias for `ls' were `ls -l' the command `ls /usr' would
926 become `ls -l /usr', the argument list here being undisturbed. If the
927 alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
928 become `grep bill /etc/passwd'. Aliases can be used to introduce
929 parser metasyntax. For example, `alias print 'pr \!* | lpr'' defines a
930 ``command'' (`print') which pr(1)s its arguments to the line printer.
931 Alias substitution is repeated until the first word of the command has
933 no alias. If an alias substitution does not change the first word (as
934 in the previous example) it is flagged to prevent a loop. Other loops
935 are detected and cause an error.
936 Some aliases are referred to by the shell; see Special aliases.
938 Variable substitution
940 The shell maintains a list of variables, each of which has as value a
941 list of zero or more words. The values of shell variables can be dis‐
942 played and changed with the set and unset commands. The system main‐
943 tains its own list of ``environment'' variables. These can be dis‐
944 played and changed with printenv, setenv and unsetenv.
945 (+) Variables may be made read-only with `set -r' (q.v.) Read-only
947 variables may not be modified or unset; attempting to do so will cause
948 an error. Once made read-only, a variable cannot be made writable, so
949 `set -r' should be used with caution. Environment variables cannot be
950 made read-only.
951 Some variables are set by the shell or referred to by it. For
953 instance, the argv variable is an image of the shell's argument list,
954 and words of this variable's value are referred to in special ways.
955 Some of the variables referred to by the shell are toggles; the shell
956 does not care what their value is, only whether they are set or not.
957 For instance, the verbose variable is a toggle which causes command
958 input to be echoed. The -v command line option sets this variable.
959 Special shell variables lists all variables which are referred to by
960 the shell.
961 Other operations treat variables numerically. The `@' command permits
963 numeric calculations to be performed and the result assigned to a vari‐
964 able. Variable values are, however, always represented as (zero or
965 more) strings. For the purposes of numeric operations, the null string
966 is considered to be zero, and the second and subsequent words of multi-
967 word values are ignored.
968 After the input line is aliased and parsed, and before each command is
970 executed, variable substitution is performed keyed by `$' characters.
971 This expansion can be prevented by preceding the `$' with a `\' except
972 within `"'s where it always occurs, and within `''s where it never
973 occurs. Strings quoted by ``' are interpreted later (see Command sub‐
974 stitution below) so `$' substitution does not occur there until later,
975 if at all. A `$' is passed unchanged if followed by a blank, tab, or
976 end-of-line.
977 Input/output redirections are recognized before variable expansion, and
979 are variable expanded separately. Otherwise, the command name and
980 entire argument list are expanded together. It is thus possible for
981 the first (command) word (to this point) to generate more than one
982 word, the first of which becomes the command name, and the rest of
983 which become arguments.
984 Unless enclosed in `"' or given the `:q' modifier the results of vari‐
986 able substitution may eventually be command and filename substituted.
987 Within `"', a variable whose value consists of multiple words expands
988 to a (portion of a) single word, with the words of the variable's value
989 separated by blanks. When the `:q' modifier is applied to a substitu‐
990 tion the variable will expand to multiple words with each word sepa‐
991 rated by a blank and quoted to prevent later command or filename sub‐
992 stitution.
993 The following metasequences are provided for introducing variable val‐
995 ues into the shell input. Except as noted, it is an error to reference
996 a variable which is not set.
997 $name
999 ${name} Substitutes the words of the value of variable name, each sepa‐
1000 rated by a blank. Braces insulate name from following charac‐
1001 ters which would otherwise be part of it. Shell variables have
1002 names consisting of letters and digits starting with a letter.
1003 The underscore character is considered a letter. If name is
1004 not a shell variable, but is set in the environment, then that
1005 value is returned (but some of the other forms given below are
1006 not available in this case).
1007 $name[selector]
1008 ${name[selector]}
1009 Substitutes only the selected words from the value of name.
1010 The selector is subjected to `$' substitution and may consist
1011 of a single number or two numbers separated by a `-'. The
1012 first word of a variable's value is numbered `1'. If the first
1013 number of a range is omitted it defaults to `1'. If the last
1014 member of a range is omitted it defaults to `$#name'. The
1015 selector `*' selects all words. It is not an error for a range
1016 to be empty if the second argument is omitted or in range.
1017 $0 Substitutes the name of the file from which command input is
1018 being read. An error occurs if the name is not known.
1019 $number
1020 ${number}
1021 Equivalent to `$argv[number]'.
1022 $* Equivalent to `$argv', which is equivalent to `$argv[*]'.
1023 The `:' modifiers described under History substitution, except for
1025 `:p', can be applied to the substitutions above. More than one may be
1026 used. (+) Braces may be needed to insulate a variable substitution
1027 from a literal colon just as with History substitution (q.v.); any mod‐
1028 ifiers must appear within the braces.
1029 The following substitutions can not be modified with `:' modifiers.
1031 $?name
1033 ${?name}
1034 Substitutes the string `1' if name is set, `0' if it is not.
1035 $?0 Substitutes `1' if the current input filename is known, `0' if
1036 it is not. Always `0' in interactive shells.
1037 $#name
1038 ${#name}
1039 Substitutes the number of words in name.
1040 $# Equivalent to `$#argv'. (+)
1041 $%name
1042 ${%name}
1043 Substitutes the number of characters in name. (+)
1044 $%number
1045 ${%number}
1046 Substitutes the number of characters in $argv[number]. (+)
1047 $? Equivalent to `$status'. (+)
1048 $$ Substitutes the (decimal) process number of the (parent) shell.
1049 $! Substitutes the (decimal) process number of the last background
1050 process started by this shell. (+)
1051 $_ Substitutes the command line of the last command executed. (+)
1052 $< Substitutes a line from the standard input, with no further
1053 interpretation thereafter. It can be used to read from the
1054 keyboard in a shell script. (+) While csh always quotes $<, as
1055 if it were equivalent to `$<:q', tcsh does not. Furthermore,
1056 when tcsh is waiting for a line to be typed the user may type
1057 an interrupt to interrupt the sequence into which the line is
1058 to be substituted, but csh does not allow this.
1059 The editor command expand-variables, normally bound to `^X-$', can be
1061 used to interactively expand individual variables.
1062 Command, filename and directory stack substitution
1064 The remaining substitutions are applied selectively to the arguments of
1065 builtin commands. This means that portions of expressions which are
1066 not evaluated are not subjected to these expansions. For commands
1067 which are not internal to the shell, the command name is substituted
1068 separately from the argument list. This occurs very late, after input-
1069 output redirection is performed, and in a child of the main shell.
1070 Command substitution
1072 Command substitution is indicated by a command enclosed in ``'. The
1073 output from such a command is broken into separate words at blanks,
1074 tabs and newlines, and null words are discarded. The output is vari‐
1075 able and command substituted and put in place of the original string.
1076 Command substitutions inside double quotes (`"') retain blanks and
1078 tabs; only newlines force new words. The single final newline does not
1079 force a new word in any case. It is thus possible for a command sub‐
1080 stitution to yield only part of a word, even if the command outputs a
1081 complete line.
1082 By default, the shell since version 6.12 replaces all newline and car‐
1084 riage return characters in the command by spaces. If this is switched
1085 off by unsetting csubstnonl, newlines separate commands as usual.
1086 Filename substitution
1088 If a word contains any of the characters `*', `?', `[' or `{' or begins
1089 with the character `~' it is a candidate for filename substitution,
1090 also known as ``globbing''. This word is then regarded as a pattern
1091 (``glob-pattern''), and replaced with an alphabetically sorted list of
1092 file names which match the pattern.
1093 In matching filenames, the character `.' at the beginning of a filename
1095 or immediately following a `/', as well as the character `/' must be
1096 matched explicitly. The character `*' matches any string of charac‐
1097 ters, including the null string. The character `?' matches any single
1098 character. The sequence `[...]' matches any one of the characters
1099 enclosed. Within `[...]', a pair of characters separated by `-'
1100 matches any character lexically between the two.
1101 (+) Some glob-patterns can be negated: The sequence `[^...]' matches
1103 any single character not specified by the characters and/or ranges of
1104 characters in the braces.
1105 An entire glob-pattern can also be negated with `^':
1107 > echo *
1109 bang crash crunch ouch
1110 > echo ^cr*
1111 bang ouch
1112 Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or
1114 `~' (below) are not negated correctly.
1115 The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'. Left-
1117 to-right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
1118 `/usr/source/s1/oldls.c /usr/source/s1/ls.c'. The results of matches
1119 are sorted separately at a low level to preserve this order:
1120 `../{memo,*box}' might expand to `../memo ../box ../mbox'. (Note that
1121 `memo' was not sorted with the results of matching `*box'.) It is not
1122 an error when this construct expands to files which do not exist, but
1123 it is possible to get an error from a command to which the expanded
1124 list is passed. This construct may be nested. As a special case the
1125 words `{', `}' and `{}' are passed undisturbed.
1126 The character `~' at the beginning of a filename refers to home direc‐
1128 tories. Standing alone, i.e., `~', it expands to the invoker's home
1129 directory as reflected in the value of the home shell variable. When
1130 followed by a name consisting of letters, digits and `-' characters the
1131 shell searches for a user with that name and substitutes their home
1132 directory; thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
1133 `/usr/ken/chmach'. If the character `~' is followed by a character
1134 other than a letter or `/' or appears elsewhere than at the beginning
1135 of a word, it is left undisturbed. A command like `setenv MANPATH
1136 /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home direc‐
1137 tory substitution as one might hope.
1138 It is an error for a glob-pattern containing `*', `?', `[' or `~', with
1140 or without `^', not to match any files. However, only one pattern in a
1141 list of glob-patterns must match a file (so that, e.g., `rm *.a *.c
1142 *.o' would fail only if there were no files in the current directory
1143 ending in `.a', `.c', or `.o'), and if the nonomatch shell variable is
1144 set a pattern (or list of patterns) which matches nothing is left
1145 unchanged rather than causing an error.
1146 The noglob shell variable can be set to prevent filename substitution,
1148 and the expand-glob editor command, normally bound to `^X-*', can be
1149 used to interactively expand individual filename substitutions.
1150 Directory stack substitution (+)
1152 The directory stack is a list of directories, numbered from zero, used
1153 by the pushd, popd and dirs builtin commands (q.v.). dirs can print,
1154 store in a file, restore and clear the directory stack at any time, and
1155 the savedirs and dirsfile shell variables can be set to store the
1156 directory stack automatically on logout and restore it on login. The
1157 dirstack shell variable can be examined to see the directory stack and
1158 set to put arbitrary directories into the directory stack.
1159 The character `=' followed by one or more digits expands to an entry in
1161 the directory stack. The special case `=-' expands to the last direc‐
1162 tory in the stack. For example,
1163 > dirs -v
1165 0 /usr/bin
1166 1 /usr/spool/uucp
1167 2 /usr/accts/sys
1168 > echo =1
1169 /usr/spool/uucp
1170 > echo =0/calendar
1171 /usr/bin/calendar
1172 > echo =-
1173 /usr/accts/sys
1174 The noglob and nonomatch shell variables and the expand-glob editor
1176 command apply to directory stack as well as filename substitutions.
1177 Other substitutions (+)
1179 There are several more transformations involving filenames, not
1180 strictly related to the above but mentioned here for completeness. Any
1181 filename may be expanded to a full path when the symlinks variable
1182 (q.v.) is set to `expand'. Quoting prevents this expansion, and the
1183 normalize-path editor command does it on demand. The normalize-command
1184 editor command expands commands in PATH into full paths on demand.
1185 Finally, cd and pushd interpret `-' as the old working directory
1186 (equivalent to the shell variable owd). This is not a substitution at
1187 all, but an abbreviation recognized by only those commands. Nonethe‐
1188 less, it too can be prevented by quoting.
1189 Commands
1191 The next three sections describe how the shell executes commands and
1192 deals with their input and output.
1193 Simple commands, pipelines and sequences
1195 A simple command is a sequence of words, the first of which specifies
1196 the command to be executed. A series of simple commands joined by `|'
1197 characters forms a pipeline. The output of each command in a pipeline
1198 is connected to the input of the next.
1199 Simple commands and pipelines may be joined into sequences with `;',
1201 and will be executed sequentially. Commands and pipelines can also be
1202 joined into sequences with `||' or `&&', indicating, as in the C lan‐
1203 guage, that the second is to be executed only if the first fails or
1204 succeeds respectively.
1205 A simple command, pipeline or sequence may be placed in parentheses,
1207 `()', to form a simple command, which may in turn be a component of a
1208 pipeline or sequence. A command, pipeline or sequence can be executed
1209 without waiting for it to terminate by following it with an `&'.
1210 Builtin and non-builtin command execution
1212 Builtin commands are executed within the shell. If any component of a
1213 pipeline except the last is a builtin command, the pipeline is executed
1214 in a subshell.
1215 Parenthesized commands are always executed in a subshell.
1217 (cd; pwd); pwd
1219 thus prints the home directory, leaving you where you were (printing
1221 this after the home directory), while
1222 cd; pwd
1224 leaves you in the home directory. Parenthesized commands are most
1226 often used to prevent cd from affecting the current shell.
1227 When a command to be executed is found not to be a builtin command the
1229 shell attempts to execute the command via execve(2). Each word in the
1230 variable path names a directory in which the shell will look for the
1231 command. If the shell is not given a -f option, the shell hashes the
1232 names in these directories into an internal table so that it will try
1233 an execve(2) in only a directory where there is a possibility that the
1234 command resides there. This greatly speeds command location when a
1235 large number of directories are present in the search path. This hash‐
1236 ing mechanism is not used:
1237 1. If hashing is turned explicitly off via unhash.
1239 2. If the shell was given a -f argument.
1241 3. For each directory component of path which does not begin with a
1243 `/'.
1244 4. If the command contains a `/'.
1246 In the above four cases the shell concatenates each component of the
1248 path vector with the given command name to form a path name of a file
1249 which it then attempts to execute it. If execution is successful, the
1250 search stops.
1251 If the file has execute permissions but is not an executable to the
1253 system (i.e., it is neither an executable binary nor a script that
1254 specifies its interpreter), then it is assumed to be a file containing
1255 shell commands and a new shell is spawned to read it. The shell spe‐
1256 cial alias may be set to specify an interpreter other than the shell
1257 itself.
1258 On systems which do not understand the `#!' script interpreter conven‐
1260 tion the shell may be compiled to emulate it; see the version shell
1261 variable. If so, the shell checks the first line of the file to see if
1262 it is of the form `#!interpreter arg ...'. If it is, the shell starts
1263 interpreter with the given args and feeds the file to it on standard
1264 input.
1265 Input/output
1267 The standard input and standard output of a command may be redirected
1268 with the following syntax:
1269 < name Open file name (which is first variable, command and filename
1271 expanded) as the standard input.
1272 << word Read the shell input up to a line which is identical to word.
1273 word is not subjected to variable, filename or command substi‐
1274 tution, and each input line is compared to word before any sub‐
1275 stitutions are done on this input line. Unless a quoting `\',
1276 `"', `' or ``' appears in word variable and command substitu‐
1277 tion is performed on the intervening lines, allowing `\' to
1278 quote `$', `\' and ``'. Commands which are substituted have
1279 all blanks, tabs, and newlines preserved, except for the final
1280 newline which is dropped. The resultant text is placed in an
1281 anonymous temporary file which is given to the command as stan‐
1282 dard input.
1283 > name
1284 >! name
1285 >& name
1286 >&! name
1287 The file name is used as standard output. If the file does not
1288 exist then it is created; if the file exists, it is truncated,
1289 its previous contents being lost.
1290 If the shell variable noclobber is set, then the file must not
1292 exist or be a character special file (e.g., a terminal or
1293 `/dev/null') or an error results. This helps prevent acciden‐
1294 tal destruction of files. In this case the `!' forms can be
1295 used to suppress this check.
1296 The forms involving `&' route the diagnostic output into the
1298 specified file as well as the standard output. name is
1299 expanded in the same way as `<' input filenames are.
1300 >> name
1301 >>& name
1302 >>! name
1303 >>&! name
1304 Like `>', but appends output to the end of name. If the shell
1305 variable noclobber is set, then it is an error for the file not
1306 to exist, unless one of the `!' forms is given.
1307 A command receives the environment in which the shell was invoked as
1309 modified by the input-output parameters and the presence of the command
1310 in a pipeline. Thus, unlike some previous shells, commands run from a
1311 file of shell commands have no access to the text of the commands by
1312 default; rather they receive the original standard input of the shell.
1313 The `<<' mechanism should be used to present inline data. This permits
1314 shell command scripts to function as components of pipelines and allows
1315 the shell to block read its input. Note that the default standard
1316 input for a command run detached is not the empty file /dev/null, but
1317 the original standard input of the shell. If this is a terminal and if
1318 the process attempts to read from the terminal, then the process will
1319 block and the user will be notified (see Jobs).
1320 Diagnostic output may be directed through a pipe with the standard out‐
1322 put. Simply use the form `|&' rather than just `|'.
1323 The shell cannot presently redirect diagnostic output without also
1325 redirecting standard output, but `(command > output-file) >& error-
1326 file' is often an acceptable workaround. Either output-file or error-
1327 file may be `/dev/tty' to send output to the terminal.
1328 Features
1330 Having described how the shell accepts, parses and executes command
1331 lines, we now turn to a variety of its useful features.
1332 Control flow
1334 The shell contains a number of commands which can be used to regulate
1335 the flow of control in command files (shell scripts) and (in limited
1336 but useful ways) from terminal input. These commands all operate by
1337 forcing the shell to reread or skip in its input and, due to the imple‐
1338 mentation, restrict the placement of some of the commands.
1339 The foreach, switch, and while statements, as well as the if-then-else
1341 form of the if statement, require that the major keywords appear in a
1342 single simple command on an input line as shown below.
1343 If the shell's input is not seekable, the shell buffers up input when‐
1345 ever a loop is being read and performs seeks in this internal buffer to
1346 accomplish the rereading implied by the loop. (To the extent that this
1347 allows, backward gotos will succeed on non-seekable inputs.)
1348 Expressions
1350 The if, while and exit builtin commands use expressions with a common
1351 syntax. The expressions can include any of the operators described in
1352 the next three sections. Note that the @ builtin command (q.v.) has
1353 its own separate syntax.
1354 Logical, arithmetical and comparison operators
1356 These operators are similar to those of C and have the same precedence.
1357 They include
1358 || && | ^ & == != =~ !~ <= >=
1360 < > << >> + - * / % ! ~ ( )
1361 Here the precedence increases to the right, `==' `!=' `=~' and `!~',
1363 `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%'
1364 being, in groups, at the same level. When multiple operators which
1365 have same precedence are used in one expression, calculation must be
1366 done from operator of right side. The `==' `!=' `=~' and `!~' opera‐
1367 tors compare their arguments as strings; all others operate on numbers.
1368 The operators `=~' and `!~' are like `!=' and `==' except that the
1369 right hand side is a glob-pattern (see Filename substitution) against
1370 which the left hand operand is matched. This reduces the need for use
1371 of the switch builtin command in shell scripts when all that is really
1372 needed is pattern matching.
1373 Null or missing arguments are considered `0'. The results of all
1375 expressions are strings, which represent decimal numbers. It is impor‐
1376 tant to note that no two components of an expression can appear in the
1377 same word; except when adjacent to components of expressions which are
1378 syntactically significant to the parser (`&' `|' `<' `>' `(' `)') they
1379 should be surrounded by spaces.
1380 Command exit status
1382 Commands can be executed in expressions and their exit status returned
1383 by enclosing them in braces (`{}'). Remember that the braces should be
1384 separated from the words of the command by spaces. Command executions
1385 succeed, returning true, i.e., `1', if the command exits with status 0,
1386 otherwise they fail, returning false, i.e., `0'. If more detailed sta‐
1387 tus information is required then the command should be executed outside
1388 of an expression and the status shell variable examined.
1389 File inquiry operators
1391 Some of these operators perform true/false tests on files and related
1392 objects. They are of the form -op file, where op is one of
1393 r Read access
1395 w Write access
1396 x Execute access
1397 X Executable in the path or shell builtin, e.g., `-X ls' and `-X
1398 ls-F' are generally true, but `-X /bin/ls' is not (+)
1399 e Existence
1400 o Ownership
1401 z Zero size
1402 s Non-zero size (+)
1403 f Plain file
1404 d Directory
1405 l Symbolic link (+) *
1406 b Block special file (+)
1407 c Character special file (+)
1408 p Named pipe (fifo) (+) *
1409 S Socket special file (+) *
1410 u Set-user-ID bit is set (+)
1411 g Set-group-ID bit is set (+)
1412 k Sticky bit is set (+)
1413 t file (which must be a digit) is an open file descriptor for a
1414 terminal device (+)
1415 R Has been migrated (convex only) (+)
1416 L Applies subsequent operators in a multiple-operator test to a
1417 symbolic link rather than to the file to which the link points
1418 (+) *
1419 file is command and filename expanded and then tested to see if it has
1421 the specified relationship to the real user. If file does not exist or
1422 is inaccessible or, for the operators indicated by `*', if the speci‐
1423 fied file type does not exist on the current system, then all enquiries
1424 return false, i.e., `0'.
1425 These operators may be combined for conciseness: `-xy file' is equiva‐
1427 lent to `-x file && -y file'. (+) For example, `-fx' is true (returns
1428 `1') for plain executable files, but not for directories.
1429 L may be used in a multiple-operator test to apply subsequent operators
1431 to a symbolic link rather than to the file to which the link points.
1432 For example, `-lLo' is true for links owned by the invoking user. Lr,
1433 Lw and Lx are always true for links and false for non-links. L has a
1434 different meaning when it is the last operator in a multiple-operator
1435 test; see below.
1436 It is possible but not useful, and sometimes misleading, to combine
1438 operators which expect file to be a file with operators which do not,
1439 (e.g., X and t). Following L with a non-file operator can lead to par‐
1440 ticularly strange results.
1441 Other operators return other information, i.e., not just `0' or `1'.
1443 (+) They have the same format as before; op may be one of
1444 A Last file access time, as the number of seconds since the
1446 epoch
1447 A: Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
1448 1993'
1449 M Last file modification time
1450 M: Like M, but in timestamp format
1451 C Last inode modification time
1452 C: Like C, but in timestamp format
1453 D Device number
1454 I Inode number
1455 F Composite file identifier, in the form device:inode
1456 L The name of the file pointed to by a symbolic link
1457 N Number of (hard) links
1458 P Permissions, in octal, without leading zero
1459 P: Like P, with leading zero
1460 Pmode Equivalent to `-P file & mode', e.g., `-P22 file' returns
1461 `22' if file is writable by group and other, `20' if by
1462 group only, and `0' if by neither
1463 Pmode: Like Pmode, with leading zero
1464 U Numeric userid
1465 U: Username, or the numeric userid if the username is unknown
1466 G Numeric groupid
1467 G: Groupname, or the numeric groupid if the groupname is
1468 unknown
1469 Z Size, in bytes
1470 Only one of these operators may appear in a multiple-operator test, and
1472 it must be the last. Note that L has a different meaning at the end of
1473 and elsewhere in a multiple-operator test. Because `0' is a valid
1474 return value for many of these operators, they do not return `0' when
1475 they fail: most return `-1', and F returns `:'.
1476 If the shell is compiled with POSIX defined (see the version shell
1478 variable), the result of a file inquiry is based on the permission bits
1479 of the file and not on the result of the access(2) system call. For
1480 example, if one tests a file with -w whose permissions would ordinarily
1481 allow writing but which is on a file system mounted read-only, the test
1482 will succeed in a POSIX shell but fail in a non-POSIX shell.
1483 File inquiry operators can also be evaluated with the filetest builtin
1485 command (q.v.) (+).
1486 Jobs
1488 The shell associates a job with each pipeline. It keeps a table of
1489 current jobs, printed by the jobs command, and assigns them small inte‐
1490 ger numbers. When a job is started asynchronously with `&', the shell
1491 prints a line which looks like
1492 [1] 1234
1494 indicating that the job which was started asynchronously was job number
1496 1 and had one (top-level) process, whose process id was 1234.
1497 If you are running a job and wish to do something else you may hit the
1499 suspend key (usually `^Z'), which sends a STOP signal to the current
1500 job. The shell will then normally indicate that the job has been `Sus‐
1501 pended' and print another prompt. If the listjobs shell variable is
1502 set, all jobs will be listed like the jobs builtin command; if it is
1503 set to `long' the listing will be in long format, like `jobs -l'. You
1504 can then manipulate the state of the suspended job. You can put it in
1505 the ``background'' with the bg command or run some other commands and
1506 eventually bring the job back into the ``foreground'' with fg. (See
1507 also the run-fg-editor editor command.) A `^Z' takes effect immedi‐
1508 ately and is like an interrupt in that pending output and unread input
1509 are discarded when it is typed. The wait builtin command causes the
1510 shell to wait for all background jobs to complete.
1511 The `^]' key sends a delayed suspend signal, which does not generate a
1513 STOP signal until a program attempts to read(2) it, to the current job.
1514 This can usefully be typed ahead when you have prepared some commands
1515 for a job which you wish to stop after it has read them. The `^Y' key
1516 performs this function in csh(1); in tcsh, `^Y' is an editing command.
1517 (+)
1518 A job being run in the background stops if it tries to read from the
1520 terminal. Background jobs are normally allowed to produce output, but
1521 this can be disabled by giving the command `stty tostop'. If you set
1522 this tty option, then background jobs will stop when they try to pro‐
1523 duce output like they do when they try to read input.
1524 There are several ways to refer to jobs in the shell. The character
1526 `%' introduces a job name. If you wish to refer to job number 1, you
1527 can name it as `%1'. Just naming a job brings it to the foreground;
1528 thus `%1' is a synonym for `fg %1', bringing job 1 back into the fore‐
1529 ground. Similarly, saying `%1 &' resumes job 1 in the background, just
1530 like `bg %1'. A job can also be named by an unambiguous prefix of the
1531 string typed in to start it: `%ex' would normally restart a suspended
1532 ex(1) job, if there were only one suspended job whose name began with
1533 the string `ex'. It is also possible to say `%?string' to specify a
1534 job whose text contains string, if there is only one such job.
1535 The shell maintains a notion of the current and previous jobs. In out‐
1537 put pertaining to jobs, the current job is marked with a `+' and the
1538 previous job with a `-'. The abbreviations `%+', `%', and (by analogy
1539 with the syntax of the history mechanism) `%%' all refer to the current
1540 job, and `%-' refers to the previous job.
1541 The job control mechanism requires that the stty(1) option `new' be set
1543 on some systems. It is an artifact from a `new' implementation of the
1544 tty driver which allows generation of interrupt characters from the
1545 keyboard to tell jobs to stop. See stty(1) and the setty builtin com‐
1546 mand for details on setting options in the new tty driver.
1547 Status reporting
1549 The shell learns immediately whenever a process changes state. It nor‐
1550 mally informs you whenever a job becomes blocked so that no further
1551 progress is possible, but only right before it prints a prompt. This
1552 is done so that it does not otherwise disturb your work. If, however,
1553 you set the shell variable notify, the shell will notify you immedi‐
1554 ately of changes of status in background jobs. There is also a shell
1555 command notify which marks a single process so that its status changes
1556 will be immediately reported. By default notify marks the current
1557 process; simply say `notify' after starting a background job to mark
1558 it.
1559 When you try to leave the shell while jobs are stopped, you will be
1561 warned that `There are suspended jobs.' You may use the jobs command to
1562 see what they are. If you do this or immediately try to exit again,
1563 the shell will not warn you a second time, and the suspended jobs will
1564 be terminated.
1565 Automatic, periodic and timed events (+)
1567 There are various ways to run commands and take other actions automati‐
1568 cally at various times in the ``life cycle'' of the shell. They are
1569 summarized here, and described in detail under the appropriate Builtin
1570 commands, Special shell variables and Special aliases.
1571 The sched builtin command puts commands in a scheduled-event list, to
1573 be executed by the shell at a given time.
1574 The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
1576 aliases can be set, respectively, to execute commands when the shell
1577 wants to ring the bell, when the working directory changes, every tpe‐
1578 riod minutes, before each prompt, before each command gets executed,
1579 after each command gets executed, and when a job is started or is
1580 brought into the foreground.
1581 The autologout shell variable can be set to log out or lock the shell
1583 after a given number of minutes of inactivity.
1584 The mail shell variable can be set to check for new mail periodically.
1586 The printexitvalue shell variable can be set to print the exit status
1588 of commands which exit with a status other than zero.
1589 The rmstar shell variable can be set to ask the user, when `rm *' is
1591 typed, if that is really what was meant.
1592 The time shell variable can be set to execute the time builtin command
1594 after the completion of any process that takes more than a given number
1595 of CPU seconds.
1596 The watch and who shell variables can be set to report when selected
1598 users log in or out, and the log builtin command reports on those users
1599 at any time.
1600 Native Language System support (+)
1602 The shell is eight bit clean (if so compiled; see the version shell
1603 variable) and thus supports character sets needing this capability.
1604 NLS support differs depending on whether or not the shell was compiled
1605 to use the system's NLS (again, see version). In either case, 7-bit
1606 ASCII is the default character code (e.g., the classification of which
1607 characters are printable) and sorting, and changing the LANG or
1608 LC_CTYPE environment variables causes a check for possible changes in
1609 these respects.
1610 When using the system's NLS, the setlocale(3) function is called to
1612 determine appropriate character code/classification and sorting (e.g.,
1613 a 'en_CA.UTF-8' would yield "UTF-8" as a character code). This func‐
1614 tion typically examines the LANG and LC_CTYPE environment variables;
1615 refer to the system documentation for further details. When not using
1616 the system's NLS, the shell simulates it by assuming that the ISO
1617 8859-1 character set is used whenever either of the LANG and LC_CTYPE
1618 variables are set, regardless of their values. Sorting is not affected
1619 for the simulated NLS.
1620 In addition, with both real and simulated NLS, all printable characters
1622 in the range \200-\377, i.e., those that have M-char bindings, are
1623 automatically rebound to self-insert-command. The corresponding bind‐
1624 ing for the escape-char sequence, if any, is left alone. These charac‐
1625 ters are not rebound if the NOREBIND environment variable is set. This
1626 may be useful for the simulated NLS or a primitive real NLS which
1627 assumes full ISO 8859-1. Otherwise, all M-char bindings in the range
1628 \240-\377 are effectively undone. Explicitly rebinding the relevant
1629 keys with bindkey is of course still possible.
1630 Unknown characters (i.e., those that are neither printable nor control
1632 characters) are printed in the format \nnn. If the tty is not in 8 bit
1633 mode, other 8 bit characters are printed by converting them to ASCII
1634 and using standout mode. The shell never changes the 7/8 bit mode of
1635 the tty and tracks user-initiated changes of 7/8 bit mode. NLS users
1636 (or, for that matter, those who want to use a meta key) may need to
1637 explicitly set the tty in 8 bit mode through the appropriate stty(1)
1638 command in, e.g., the ~/.login file.
1639 OS variant support (+)
1641 A number of new builtin commands are provided to support features in
1642 particular operating systems. All are described in detail in the
1643 Builtin commands section.
1644 On systems that support TCF (aix-ibm370, aix-ps2), getspath and
1646 setspath get and set the system execution path, getxvers and setxvers
1647 get and set the experimental version prefix and migrate migrates pro‐
1648 cesses between sites. The jobs builtin prints the site on which each
1649 job is executing.
1650 Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
1652 operating system.
1653 Under Domain/OS, inlib adds shared libraries to the current environ‐
1655 ment, rootnode changes the rootnode and ver changes the systype.
1656 Under Mach, setpath is equivalent to Mach's setpath(1).
1658 Under Masscomp/RTU and Harris CX/UX, universe sets the universe.
1660 Under Harris CX/UX, ucb or att runs a command under the specified uni‐
1662 verse.
1663 Under Convex/OS, warp prints or sets the universe.
1665 The VENDOR, OSTYPE and MACHTYPE environment variables indicate respec‐
1667 tively the vendor, operating system and machine type (microprocessor
1668 class or machine model) of the system on which the shell thinks it is
1669 running. These are particularly useful when sharing one's home direc‐
1670 tory between several types of machines; one can, for example,
1671 set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)
1673 in one's ~/.login and put executables compiled for each machine in the
1675 appropriate directory.
1676 The version shell variable indicates what options were chosen when the
1678 shell was compiled.
1679 Note also the newgrp builtin, the afsuser and echo_style shell vari‐
1681 ables and the system-dependent locations of the shell's input files
1682 (see FILES).
1683 Signal handling
1685 Login shells ignore interrupts when reading the file ~/.logout. The
1686 shell ignores quit signals unless started with -q. Login shells catch
1687 the terminate signal, but non-login shells inherit the terminate behav‐
1688 ior from their parents. Other signals have the values which the shell
1689 inherited from its parent.
1690 In shell scripts, the shell's handling of interrupt and terminate sig‐
1692 nals can be controlled with onintr, and its handling of hangups can be
1693 controlled with hup and nohup.
1694 The shell exits on a hangup (see also the logout shell variable). By
1696 default, the shell's children do too, but the shell does not send them
1697 a hangup when it exits. hup arranges for the shell to send a hangup to
1698 a child when it exits, and nohup sets a child to ignore hangups.
1699 Terminal management (+)
1701 The shell uses three different sets of terminal (``tty'') modes:
1702 `edit', used when editing, `quote', used when quoting literal charac‐
1703 ters, and `execute', used when executing commands. The shell holds
1704 some settings in each mode constant, so commands which leave the tty in
1705 a confused state do not interfere with the shell. The shell also
1706 matches changes in the speed and padding of the tty. The list of tty
1707 modes that are kept constant can be examined and modified with the
1708 setty builtin. Note that although the editor uses CBREAK mode (or its
1709 equivalent), it takes typed-ahead characters anyway.
1710 The echotc, settc and telltc commands can be used to manipulate and
1712 debug terminal capabilities from the command line.
1713 On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win‐
1715 dow resizing automatically and adjusts the environment variables LINES
1716 and COLUMNS if set. If the environment variable TERMCAP contains li#
1717 and co# fields, the shell adjusts them to reflect the new window size.
1718
1720 The next sections of this manual describe all of the available Builtin
1721 commands, Special aliases and Special shell variables.
1722 Builtin commands
1724 %job A synonym for the fg builtin command.
1725 %job & A synonym for the bg builtin command.
1727 : Does nothing, successfully.
1729 @
1731 @ name = expr
1732 @ name[index] = expr
1733 @ name++|--
1734 @ name[index]++|--
1735 The first form prints the values of all shell variables.
1736 The second form assigns the value of expr to name. The third
1738 form assigns the value of expr to the index'th component of
1739 name; both name and its index'th component must already exist.
1740 expr may contain the operators `*', `+', etc., as in C. If
1742 expr contains `<', `>', `&' or `' then at least that part of
1743 expr must be placed within `()'. Note that the syntax of expr
1744 has nothing to do with that described under Expressions.
1745 The fourth and fifth forms increment (`++') or decrement (`--')
1747 name or its index'th component.
1748 The space between `@' and name is required. The spaces between
1750 name and `=' and between `=' and expr are optional. Components
1751 of expr must be separated by spaces.
1752 alias [name [wordlist]]
1754 Without arguments, prints all aliases. With name, prints the
1755 alias for name. With name and wordlist, assigns wordlist as
1756 the alias of name. wordlist is command and filename substi‐
1757 tuted. name may not be `alias' or `unalias'. See also the
1758 unalias builtin command.
1759 alloc Shows the amount of dynamic memory acquired, broken down into
1761 used and free memory. With an argument shows the number of
1762 free and used blocks in each size category. The categories
1763 start at size 8 and double at each step. This command's output
1764 may vary across system types, because systems other than the
1765 VAX may use a different memory allocator.
1766 bg [%job ...]
1768 Puts the specified jobs (or, without arguments, the current
1769 job) into the background, continuing each if it is stopped.
1770 job may be a number, a string, `', `%', `+' or `-' as described
1771 under Jobs.
1772 bindkey [-l|-d|-e|-v|-u] (+)
1774 bindkey [-a] [-b] [-k] [-r] [--] key (+)
1775 bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
1776 Without options, the first form lists all bound keys and the
1777 editor command to which each is bound, the second form lists
1778 the editor command to which key is bound and the third form
1779 binds the editor command command to key. Options include:
1780 -l Lists all editor commands and a short description of each.
1782 -d Binds all keys to the standard bindings for the default
1783 editor.
1784 -e Binds all keys to the standard GNU Emacs-like bindings.
1785 -v Binds all keys to the standard vi(1)-like bindings.
1786 -a Lists or changes key-bindings in the alternative key map.
1787 This is the key map used in vi command mode.
1788 -b key is interpreted as a control character written ^charac‐
1789 ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char‐
1790 acter written M-character (e.g., `M-A'), a function key
1791 written F-string (e.g., `F-string'), or an extended prefix
1792 key written X-character (e.g., `X-A').
1793 -k key is interpreted as a symbolic arrow key name, which may
1794 be one of `down', `up', `left' or `right'.
1795 -r Removes key's binding. Be careful: `bindkey -r' does not
1796 bind key to self-insert-command (q.v.), it unbinds key com‐
1797 pletely.
1798 -c command is interpreted as a builtin or external command
1799 instead of an editor command.
1800 -s command is taken as a literal string and treated as termi‐
1801 nal input when key is typed. Bound keys in command are
1802 themselves reinterpreted, and this continues for ten levels
1803 of interpretation.
1804 -- Forces a break from option processing, so the next word is
1805 taken as key even if it begins with '-'.
1806 -u (or any invalid option)
1807 Prints a usage message.
1808 key may be a single character or a string. If a command is
1810 bound to a string, the first character of the string is bound
1811 to sequence-lead-in and the entire string is bound to the com‐
1812 mand.
1813 Control characters in key can be literal (they can be typed by
1815 preceding them with the editor command quoted-insert, normally
1816 bound to `^V') or written caret-character style, e.g., `^A'.
1817 Delete is written `^?' (caret-question mark). key and command
1818 can contain backslashed escape sequences (in the style of Sys‐
1819 tem V echo(1)) as follows:
1820 \a Bell
1822 \b Backspace
1823 \e Escape
1824 \f Form feed
1825 \n Newline
1826 \r Carriage return
1827 \t Horizontal tab
1828 \v Vertical tab
1829 \nnn The ASCII character corresponding to the octal num‐
1830 ber nnn
1831 `\' nullifies the special meaning of the following character,
1833 if it has any, notably `\' and `^'.
1834 bs2cmd bs2000-command (+)
1836 Passes bs2000-command to the BS2000 command interpreter for
1837 execution. Only non-interactive commands can be executed, and
1838 it is not possible to execute any command that would overlay
1839 the image of the current process, like /EXECUTE or /CALL-PROCE‐
1840 DURE. (BS2000 only)
1841 break Causes execution to resume after the end of the nearest enclos‐
1843 ing foreach or while. The remaining commands on the current
1844 line are executed. Multi-level breaks are thus possible by
1845 writing them all on one line.
1846 breaksw Causes a break from a switch, resuming after the endsw.
1848 builtins (+)
1850 Prints the names of all builtin commands.
1851 bye (+) A synonym for the logout builtin command. Available only if
1853 the shell was so compiled; see the version shell variable.
1854 case label:
1856 A label in a switch statement as discussed below.
1857 cd [-p] [-l] [-n|-v] [name]
1859 If a directory name is given, changes the shell's working
1860 directory to name. If not, changes to home. If name is `-' it
1861 is interpreted as the previous working directory (see Other
1862 substitutions). (+) If name is not a subdirectory of the cur‐
1863 rent directory (and does not begin with `/', `./' or `../'),
1864 each component of the variable cdpath is checked to see if it
1865 has a subdirectory name. Finally, if all else fails but name
1866 is a shell variable whose value begins with `/', then this is
1867 tried to see if it is a directory.
1868 With -p, prints the final directory stack, just like dirs. The
1870 -l, -n and -v flags have the same effect on cd as on dirs, and
1871 they imply -p. (+)
1872 See also the implicitcd shell variable.
1874 chdir A synonym for the cd builtin command.
1876 complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
1878 Without arguments, lists all completions. With command, lists
1879 completions for command. With command and word etc., defines
1880 completions.
1881 command may be a full command name or a glob-pattern (see File‐
1883 name substitution). It can begin with `-' to indicate that
1884 completion should be used only when command is ambiguous.
1885 word specifies which word relative to the current word is to be
1887 completed, and may be one of the following:
1888 c Current-word completion. pattern is a glob-pattern
1890 which must match the beginning of the current word on
1891 the command line. pattern is ignored when completing
1892 the current word.
1893 C Like c, but includes pattern when completing the cur‐
1894 rent word.
1895 n Next-word completion. pattern is a glob-pattern which
1896 must match the beginning of the previous word on the
1897 command line.
1898 N Like n, but must match the beginning of the word two
1899 before the current word.
1900 p Position-dependent completion. pattern is a numeric
1901 range, with the same syntax used to index shell vari‐
1902 ables, which must include the current word.
1903 list, the list of possible completions, may be one of the fol‐
1905 lowing:
1906 a Aliases
1908 b Bindings (editor commands)
1909 c Commands (builtin or external commands)
1910 C External commands which begin with the supplied
1911 path prefix
1912 d Directories
1913 D Directories which begin with the supplied path pre‐
1914 fix
1915 e Environment variables
1916 f Filenames
1917 F Filenames which begin with the supplied path prefix
1918 g Groupnames
1919 j Jobs
1920 l Limits
1921 n Nothing
1922 s Shell variables
1923 S Signals
1924 t Plain (``text'') files
1925 T Plain (``text'') files which begin with the sup‐
1926 plied path prefix
1927 v Any variables
1928 u Usernames
1929 x Like n, but prints select when list-choices is
1930 used.
1931 X Completions
1932 $var Words from the variable var
1933 (...) Words from the given list
1934 `...` Words from the output of command
1935 select is an optional glob-pattern. If given, words from only
1937 list that match select are considered and the fignore shell
1938 variable is ignored. The last three types of completion may
1939 not have a select pattern, and x uses select as an explanatory
1940 message when the list-choices editor command is used.
1941 suffix is a single character to be appended to a successful
1943 completion. If null, no character is appended. If omitted (in
1944 which case the fourth delimiter can also be omitted), a slash
1945 is appended to directories and a space to other words.
1946 command invoked from `...` version has additional environment
1948 variable set, the variable name is COMMAND_LINE and contains
1949 (as its name indicates) contents of the current (already typed
1950 in) command line. One can examine and use contents of the
1951 COMMAND_LINE variable in her custom script to build more
1952 sophisticated completions (see completion for svn(1) included
1953 in this package).
1954 Now for some examples. Some commands take only directories as
1956 arguments, so there's no point completing plain files.
1957 > complete cd 'p/1/d/'
1959 completes only the first word following `cd' (`p/1') with a
1961 directory. p-type completion can also be used to narrow down
1962 command completion:
1963 > co[^D]
1965 complete compress
1966 > complete -co* 'p/0/(compress)/'
1967 > co[^D]
1968 > compress
1969 This completion completes commands (words in position 0, `p/0')
1971 which begin with `co' (thus matching `co*') to `compress' (the
1972 only word in the list). The leading `-' indicates that this
1973 completion is to be used with only ambiguous commands.
1974 > complete find 'n/-user/u/'
1976 is an example of n-type completion. Any word following `find'
1978 and immediately following `-user' is completed from the list of
1979 users.
1980 > complete cc 'c/-I/d/'
1982 demonstrates c-type completion. Any word following `cc' and
1984 beginning with `-I' is completed as a directory. `-I' is not
1985 taken as part of the directory because we used lowercase c.
1986 Different lists are useful with different commands.
1988 > complete alias 'p/1/a/'
1990 > complete man 'p/*/c/'
1991 > complete set 'p/1/s/'
1992 > complete true 'p/1/x:Truth has no options./'
1993 These complete words following `alias' with aliases, `man' with
1995 commands, and `set' with shell variables. `true' doesn't have
1996 any options, so x does nothing when completion is attempted and
1997 prints `Truth has no options.' when completion choices are
1998 listed.
1999 Note that the man example, and several other examples below,
2001 could just as well have used 'c/*' or 'n/*' as 'p/*'.
2002 Words can be completed from a variable evaluated at completion
2004 time,
2005 > complete ftp 'p/1/$hostnames/'
2007 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
2008 > ftp [^D]
2009 rtfm.mit.edu tesla.ee.cornell.edu
2010 > ftp [^C]
2011 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
2012 uunet.uu.net)
2013 > ftp [^D]
2014 rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net
2015 or from a command run at completion time:
2017 > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
2019 > kill -9 [^D]
2020 23113 23377 23380 23406 23429 23529 23530 PID
2021 Note that the complete command does not itself quote its argu‐
2023 ments, so the braces, space and `$' in `{print $1}' must be
2024 quoted explicitly.
2025 One command can have multiple completions:
2027 > complete dbx 'p/2/(core)/' 'p/*/c/'
2029 completes the second argument to `dbx' with the word `core' and
2031 all other arguments with commands. Note that the positional
2032 completion is specified before the next-word completion.
2033 Because completions are evaluated from left to right, if the
2034 next-word completion were specified first it would always match
2035 and the positional completion would never be executed. This is
2036 a common mistake when defining a completion.
2037 The select pattern is useful when a command takes files with
2039 only particular forms as arguments. For example,
2040 > complete cc 'p/*/f:*.[cao]/'
2042 completes `cc' arguments to files ending in only `.c', `.a', or
2044 `.o'. select can also exclude files, using negation of a glob-
2045 pattern as described under Filename substitution. One might
2046 use
2047 > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'
2049 to exclude precious source code from `rm' completion. Of
2051 course, one could still type excluded names manually or over‐
2052 ride the completion mechanism using the complete-word-raw or
2053 list-choices-raw editor commands (q.v.).
2054 The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
2056 respectively, but they use the select argument in a different
2057 way: to restrict completion to files beginning with a particu‐
2058 lar path prefix. For example, the Elm mail program uses `=' as
2059 an abbreviation for one's mail directory. One might use
2060 > complete elm c@=@F:$HOME/Mail/@
2062 to complete `elm -f =' as if it were `elm -f ~/Mail/'. Note
2064 that we used `@' instead of `/' to avoid confusion with the
2065 select argument, and we used `$HOME' instead of `~' because
2066 home directory substitution works at only the beginning of a
2067 word.
2068 suffix is used to add a nonstandard suffix (not space or `/'
2070 for directories) to completed words.
2071 > complete finger 'c/*@/$hostnames/' 'p/1/u/@'
2073 completes arguments to `finger' from the list of users, appends
2075 an `@', and then completes after the `@' from the `hostnames'
2076 variable. Note again the order in which the completions are
2077 specified.
2078 Finally, here's a complex example for inspiration:
2080 > complete find \
2082 'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
2083 ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
2084 'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
2085 'n/-type/(b c d f l p s)/' \
2086 ´c/-/(name newer cpio ncpio exec ok user \
2087 group fstype type atime ctime depth inum \
2088 ls mtime nogroup nouser perm print prune \
2089 size xdev)/' \
2090 'p/*/d/'
2091 This completes words following `-name', `-newer', `-cpio' or
2093 `ncpio' (note the pattern which matches both) to files, words
2094 following `-exec' or `-ok' to commands, words following `user'
2095 and `group' to users and groups respectively and words follow‐
2096 ing `-fstype' or `-type' to members of the given lists. It
2097 also completes the switches themselves from the given list
2098 (note the use of c-type completion) and completes anything not
2099 otherwise completed to a directory. Whew.
2100 Remember that programmed completions are ignored if the word
2102 being completed is a tilde substitution (beginning with `~') or
2103 a variable (beginning with `$'). complete is an experimental
2104 feature, and the syntax may change in future versions of the
2105 shell. See also the uncomplete builtin command.
2106 continue
2108 Continues execution of the nearest enclosing while or foreach.
2109 The rest of the commands on the current line are executed.
2110 default:
2112 Labels the default case in a switch statement. It should come
2113 after all case labels.
2114 dirs [-l] [-n|-v]
2116 dirs -S|-L [filename] (+)
2117 dirs -c (+)
2118 The first form prints the directory stack. The top of the
2119 stack is at the left and the first directory in the stack is
2120 the current directory. With -l, `~' or `~name' in the output
2121 is expanded explicitly to home or the pathname of the home
2122 directory for user name. (+) With -n, entries are wrapped
2123 before they reach the edge of the screen. (+) With -v, entries
2124 are printed one per line, preceded by their stack positions.
2125 (+) If more than one of -n or -v is given, -v takes precedence.
2126 -p is accepted but does nothing.
2127 With -S, the second form saves the directory stack to filename
2129 as a series of cd and pushd commands. With -L, the shell
2130 sources filename, which is presumably a directory stack file
2131 saved by the -S option or the savedirs mechanism. In either
2132 case, dirsfile is used if filename is not given and ~/.cshdirs
2133 is used if dirsfile is unset.
2134 Note that login shells do the equivalent of `dirs -L' on
2136 startup and, if savedirs is set, `dirs -S' before exiting.
2137 Because only ~/.tcshrc is normally sourced before ~/.cshdirs,
2138 dirsfile should be set in ~/.tcshrc rather than ~/.login.
2139 The last form clears the directory stack.
2141 echo [-n] word ...
2143 Writes each word to the shell's standard output, separated by
2144 spaces and terminated with a newline. The echo_style shell
2145 variable may be set to emulate (or not) the flags and escape
2146 sequences of the BSD and/or System V versions of echo; see
2147 echo(1).
2148 echotc [-sv] arg ... (+)
2150 Exercises the terminal capabilities (see termcap(5)) in args.
2151 For example, 'echotc home' sends the cursor to the home posi‐
2152 tion, 'echotc cm 3 10' sends it to column 3 and row 10, and
2153 'echotc ts 0; echo "This is a test."; echotc fs' prints "This
2154 is a test." in the status line.
2155 If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
2157 value of that capability ("yes" or "no" indicating that the
2158 terminal does or does not have that capability). One might use
2159 this to make the output from a shell script less verbose on
2160 slow terminals, or limit command output to the number of lines
2161 on the screen:
2162 > set history=`echotc lines`
2164 > @ history--
2165 Termcap strings may contain wildcards which will not echo cor‐
2167 rectly. One should use double quotes when setting a shell
2168 variable to a terminal capability string, as in the following
2169 example that places the date in the status line:
2170 > set tosl="`echotc ts 0`"
2172 > set frsl="`echotc fs`"
2173 > echo -n "$tosl";date; echo -n "$frsl"
2174 With -s, nonexistent capabilities return the empty string
2176 rather than causing an error. With -v, messages are verbose.
2177 else
2179 end
2180 endif
2181 endsw See the description of the foreach, if, switch, and while
2182 statements below.
2183 eval arg ...
2185 Treats the arguments as input to the shell and executes the
2186 resulting command(s) in the context of the current shell. This
2187 is usually used to execute commands generated as the result of
2188 command or variable substitution, because parsing occurs before
2189 these substitutions. See tset(1) for a sample use of eval.
2190 exec command
2192 Executes the specified command in place of the current shell.
2193 exit [expr]
2195 The shell exits either with the value of the specified expr (an
2196 expression, as described under Expressions) or, without expr,
2197 with the value 0.
2198 fg [%job ...]
2200 Brings the specified jobs (or, without arguments, the current
2201 job) into the foreground, continuing each if it is stopped.
2202 job may be a number, a string, `', `%', `+' or `-' as described
2203 under Jobs. See also the run-fg-editor editor command.
2204 filetest -op file ... (+)
2206 Applies op (which is a file inquiry operator as described under
2207 File inquiry operators) to each file and returns the results as
2208 a space-separated list.
2209 foreach name (wordlist)
2211 ...
2212 end Successively sets the variable name to each member of wordlist
2213 and executes the sequence of commands between this command and
2214 the matching end. (Both foreach and end must appear alone on
2215 separate lines.) The builtin command continue may be used to
2216 continue the loop prematurely and the builtin command break to
2217 terminate it prematurely. When this command is read from the
2218 terminal, the loop is read once prompting with `foreach? ' (or
2219 prompt2) before any statements in the loop are executed. If
2220 you make a mistake typing in a loop at the terminal you can rub
2221 it out.
2222 getspath (+)
2224 Prints the system execution path. (TCF only)
2225 getxvers (+)
2227 Prints the experimental version prefix. (TCF only)
2228 glob wordlist
2230 Like echo, but the `-n' parameter is not recognized and words
2231 are delimited by null characters in the output. Useful for
2232 programs which wish to use the shell to filename expand a list
2233 of words.
2234 goto word
2236 word is filename and command-substituted to yield a string of
2237 the form `label'. The shell rewinds its input as much as pos‐
2238 sible, searches for a line of the form `label:', possibly pre‐
2239 ceded by blanks or tabs, and continues execution after that
2240 line.
2241 hashstat
2243 Prints a statistics line indicating how effective the internal
2244 hash table has been at locating commands (and avoiding exec's).
2245 An exec is attempted for each component of the path where the
2246 hash function indicates a possible hit, and in each component
2247 which does not begin with a `/'.
2248 On machines without vfork(2), prints only the number and size
2250 of hash buckets.
2251 history [-hTr] [n]
2253 history -S|-L|-M [filename] (+)
2254 history -c (+)
2255 The first form prints the history event list. If n is given
2256 only the n most recent events are printed or saved. With -h,
2257 the history list is printed without leading numbers. If -T is
2258 specified, timestamps are printed also in comment form. (This
2259 can be used to produce files suitable for loading with 'history
2260 -L' or 'source -h'.) With -r, the order of printing is most
2261 recent first rather than oldest first.
2262 With -S, the second form saves the history list to filename.
2264 If the first word of the savehist shell variable is set to a
2265 number, at most that many lines are saved. If the second word
2266 of savehist is set to `merge', the history list is merged with
2267 the existing history file instead of replacing it (if there is
2268 one) and sorted by time stamp. (+) Merging is intended for an
2269 environment like the X Window System with several shells in
2270 simultaneous use. Currently it succeeds only when the shells
2271 quit nicely one after another.
2272 With -L, the shell appends filename, which is presumably a his‐
2274 tory list saved by the -S option or the savehist mechanism, to
2275 the history list. -M is like -L, but the contents of filename
2276 are merged into the history list and sorted by timestamp. In
2277 either case, histfile is used if filename is not given and
2278 ~/.history is used if histfile is unset. `history -L' is
2279 exactly like 'source -h' except that it does not require a
2280 filename.
2281 Note that login shells do the equivalent of `history -L' on
2283 startup and, if savehist is set, `history -S' before exiting.
2284 Because only ~/.tcshrc is normally sourced before ~/.history,
2285 histfile should be set in ~/.tcshrc rather than ~/.login.
2286 If histlit is set, the first and second forms print and save
2288 the literal (unexpanded) form of the history list.
2289 The last form clears the history list.
2291 hup [command] (+)
2293 With command, runs command such that it will exit on a hangup
2294 signal and arranges for the shell to send it a hangup signal
2295 when the shell exits. Note that commands may set their own
2296 response to hangups, overriding hup. Without an argument
2297 (allowed in only a shell script), causes the shell to exit on a
2298 hangup for the remainder of the script. See also Signal han‐
2299 dling and the nohup builtin command.
2300 if (expr) command
2302 If expr (an expression, as described under Expressions) evalu‐
2303 ates true, then command is executed. Variable substitution on
2304 command happens early, at the same time it does for the rest of
2305 the if command. command must be a simple command, not an
2306 alias, a pipeline, a command list or a parenthesized command
2307 list, but it may have arguments. Input/output redirection
2308 occurs even if expr is false and command is thus not executed;
2309 this is a bug.
2310 if (expr) then
2312 ...
2313 else if (expr2) then
2314 ...
2315 else
2316 ...
2317 endif If the specified expr is true then the commands to the first
2318 else are executed; otherwise if expr2 is true then the commands
2319 to the second else are executed, etc. Any number of else-if
2320 pairs are possible; only one endif is needed. The else part is
2321 likewise optional. (The words else and endif must appear at
2322 the beginning of input lines; the if must appear alone on its
2323 input line or after an else.)
2324 inlib shared-library ... (+)
2326 Adds each shared-library to the current environment. There is
2327 no way to remove a shared library. (Domain/OS only)
2328 jobs [-l]
2330 Lists the active jobs. With -l, lists process IDs in addition
2331 to the normal information. On TCF systems, prints the site on
2332 which each job is executing.
2333 kill [-s signal] %job|pid ...
2335 kill -l The first and second forms sends the specified signal (or, if
2336 none is given, the TERM (terminate) signal) to the specified
2337 jobs or processes. job may be a number, a string, `', `%', `+'
2338 or `-' as described under Jobs. Signals are either given by
2339 number or by name (as given in /usr/include/signal.h, stripped
2340 of the prefix `SIG'). There is no default job; saying just
2341 `kill' does not send a signal to the current job. If the sig‐
2342 nal being sent is TERM (terminate) or HUP (hangup), then the
2343 job or process is sent a CONT (continue) signal as well. The
2344 third form lists the signal names.
2345 limit [-h] [resource [maximum-use]]
2347 Limits the consumption by the current process and each process
2348 it creates to not individually exceed maximum-use on the speci‐
2349 fied resource. If no maximum-use is given, then the current
2350 limit is printed; if no resource is given, then all limitations
2351 are given. If the -h flag is given, the hard limits are used
2352 instead of the current limits. The hard limits impose a ceil‐
2353 ing on the values of the current limits. Only the super-user
2354 may raise the hard limits, but a user may lower or raise the
2355 current limits within the legal range.
2356 Controllable resources currently include (if supported by the
2358 OS):
2359 cputime
2361 the maximum number of cpu-seconds to be used by each
2362 process
2363 filesize
2365 the largest single file which can be created
2366 datasize
2368 the maximum growth of the data+stack region via sbrk(2)
2369 beyond the end of the program text
2370 stacksize
2372 the maximum size of the automatically-extended stack
2373 region
2374 coredumpsize
2376 the size of the largest core dump that will be created
2377 memoryuse
2379 the maximum amount of physical memory a process may have
2380 allocated to it at a given time (this is not implemented
2381 in the 2.6 kernel. The value is meaningless and changing
2382 this value will have no effect)
2383 heapsize
2385 the maximum amount of memory a process may allocate per
2386 brk() system call
2387 descriptors or openfiles
2389 the maximum number of open files for this process
2390 concurrency
2392 the maximum number of threads for this process
2393 memorylocked
2395 the maximum size which a process may lock into memory
2396 using mlock(2)
2397 maxproc
2399 the maximum number of simultaneous processes for this
2400 user id
2401 sbsize the maximum size of socket buffer usage for this user
2403 swapsize
2405 the maximum amount of swap space reserved or used for
2406 this user
2407 maximum-use may be given as a (floating point or integer) num‐
2409 ber followed by a scale factor. For all limits other than
2410 cputime the default scale is `k' or `kilobytes' (1024 bytes); a
2411 scale factor of `m' or `megabytes' may also be used. For
2412 cputime the default scaling is `seconds', while `m' for minutes
2413 or `h' for hours, or a time of the form `mm:ss' giving minutes
2414 and seconds may be used.
2415 For both resource names and scale factors, unambiguous prefixes
2417 of the names suffice.
2418 log (+) Prints the watch shell variable and reports on each user indi‐
2420 cated in watch who is logged in, regardless of when they last
2421 logged in. See also watchlog.
2422 login Terminates a login shell, replacing it with an instance of
2424 /bin/login. This is one way to log off, included for compati‐
2425 bility with sh(1).
2426 logout Terminates a login shell. Especially useful if ignoreeof is
2428 set.
2429 ls-F [-switch ...] [file ...] (+)
2431 Lists files like `ls -F', but much faster. It identifies each
2432 type of special file in the listing with a special character:
2433 / Directory
2435 * Executable
2436 # Block device
2437 % Character device
2438 | Named pipe (systems with named pipes only)
2439 = Socket (systems with sockets only)
2440 @ Symbolic link (systems with symbolic links only)
2441 + Hidden directory (AIX only) or context dependent (HP/UX
2442 only)
2443 : Network special (HP/UX only)
2444 If the listlinks shell variable is set, symbolic links are
2446 identified in more detail (on only systems that have them, of
2447 course):
2448 @ Symbolic link to a non-directory
2450 > Symbolic link to a directory
2451 & Symbolic link to nowhere
2452 listlinks also slows down ls-F and causes partitions holding
2454 files pointed to by symbolic links to be mounted.
2455 If the listflags shell variable is set to `x', `a' or `A', or
2457 any combination thereof (e.g., `xA'), they are used as flags to
2458 ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com‐
2459 bination (e.g., `ls -FxA'). On machines where `ls -C' is not
2460 the default, ls-F acts like `ls -CF', unless listflags contains
2461 an `x', in which case it acts like `ls -xF'. ls-F passes its
2462 arguments to ls(1) if it is given any switches, so `alias ls
2463 ls-F' generally does the right thing.
2464 The ls-F builtin can list files using different colors depend‐
2466 ing on the filetype or extension. See the color tcsh variable
2467 and the LS_COLORS environment variable.
2468 migrate [-site] pid|%jobid ... (+)
2470 migrate -site (+)
2471 The first form migrates the process or job to the site speci‐
2472 fied or the default site determined by the system path. The
2473 second form is equivalent to `migrate -site $$': it migrates
2474 the current process to the specified site. Migrating the shell
2475 itself can cause unexpected behavior, because the shell does
2476 not like to lose its tty. (TCF only)
2477 newgrp [-] group (+)
2479 Equivalent to `exec newgrp'; see newgrp(1). Available only if
2480 the shell was so compiled; see the version shell variable.
2481 nice [+number] [command]
2483 Sets the scheduling priority for the shell to number, or, with‐
2484 out number, to 4. With command, runs command at the appropri‐
2485 ate priority. The greater the number, the less cpu the process
2486 gets. The super-user may specify negative priority by using
2487 `nice -number ...'. Command is always executed in a sub-shell,
2488 and the restrictions placed on commands in simple if statements
2489 apply.
2490 nohup [command]
2492 With command, runs command such that it will ignore hangup sig‐
2493 nals. Note that commands may set their own response to
2494 hangups, overriding nohup. Without an argument (allowed in
2495 only a shell script), causes the shell to ignore hangups for
2496 the remainder of the script. See also Signal handling and the
2497 hup builtin command.
2498 notify [%job ...]
2500 Causes the shell to notify the user asynchronously when the
2501 status of any of the specified jobs (or, without %job, the cur‐
2502 rent job) changes, instead of waiting until the next prompt as
2503 is usual. job may be a number, a string, `', `%', `+' or `-'
2504 as described under Jobs. See also the notify shell variable.
2505 onintr [-|label]
2507 Controls the action of the shell on interrupts. Without argu‐
2508 ments, restores the default action of the shell on interrupts,
2509 which is to terminate shell scripts or to return to the termi‐
2510 nal command input level. With `-', causes all interrupts to be
2511 ignored. With label, causes the shell to execute a `goto
2512 label' when an interrupt is received or a child process termi‐
2513 nates because it was interrupted.
2514 onintr is ignored if the shell is running detached and in sys‐
2516 tem startup files (see FILES), where interrupts are disabled
2517 anyway.
2518 popd [-p] [-l] [-n|-v] [+n]
2520 Without arguments, pops the directory stack and returns to the
2521 new top directory. With a number `+n', discards the n'th entry
2522 in the stack.
2523 Finally, all forms of popd print the final directory stack,
2525 just like dirs. The pushdsilent shell variable can be set to
2526 prevent this and the -p flag can be given to override pushdsi‐
2527 lent. The -l, -n and -v flags have the same effect on popd as
2528 on dirs. (+)
2529 printenv [name] (+)
2531 Prints the names and values of all environment variables or,
2532 with name, the value of the environment variable name.
2533 pushd [-p] [-l] [-n|-v] [name|+n]
2535 Without arguments, exchanges the top two elements of the direc‐
2536 tory stack. If pushdtohome is set, pushd without arguments
2537 does `pushd ~', like cd. (+) With name, pushes the current
2538 working directory onto the directory stack and changes to name.
2539 If name is `-' it is interpreted as the previous working direc‐
2540 tory (see Filename substitution). (+) If dunique is set, pushd
2541 removes any instances of name from the stack before pushing it
2542 onto the stack. (+) With a number `+n', rotates the nth ele‐
2543 ment of the directory stack around to be the top element and
2544 changes to it. If dextract is set, however, `pushd +n'
2545 extracts the nth directory, pushes it onto the top of the stack
2546 and changes to it. (+)
2547 Finally, all forms of pushd print the final directory stack,
2549 just like dirs. The pushdsilent shell variable can be set to
2550 prevent this and the -p flag can be given to override pushdsi‐
2551 lent. The -l, -n and -v flags have the same effect on pushd as
2552 on dirs. (+)
2553 rehash Causes the internal hash table of the contents of the directo‐
2555 ries in the path variable to be recomputed. This is needed if
2556 new commands are added to directories in path while you are
2557 logged in. This should be necessary only if you add commands
2558 to one of your own directories, or if a systems programmer
2559 changes the contents of one of the system directories. Also
2560 flushes the cache of home directories built by tilde expansion.
2561 repeat count command
2563 The specified command, which is subject to the same restric‐
2564 tions as the command in the one line if statement above, is
2565 executed count times. I/O redirections occur exactly once,
2566 even if count is 0.
2567 rootnode //nodename (+)
2569 Changes the rootnode to //nodename, so that `/' will be inter‐
2570 preted as `//nodename'. (Domain/OS only)
2571 sched (+)
2573 sched [+]hh:mm command (+)
2574 sched -n (+)
2575 The first form prints the scheduled-event list. The sched
2576 shell variable may be set to define the format in which the
2577 scheduled-event list is printed. The second form adds command
2578 to the scheduled-event list. For example,
2579 > sched 11:00 echo It\'s eleven o\'clock.
2581 causes the shell to echo `It's eleven o'clock.' at 11 AM. The
2583 time may be in 12-hour AM/PM format
2584 > sched 5pm set prompt='[%h] It\'s after 5; go home: >'
2586 or may be relative to the current time:
2588 > sched +2:15 /usr/lib/uucp/uucico -r1 -sother
2590 A relative time specification may not use AM/PM format. The
2592 third form removes item n from the event list:
2593 > sched
2595 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2596 2 Wed Apr 4 17:00 set prompt=[%h] It's after 5; go
2597 home: >
2598 > sched -2
2599 > sched
2600 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2601 A command in the scheduled-event list is executed just before
2603 the first prompt is printed after the time when the command is
2604 scheduled. It is possible to miss the exact time when the com‐
2605 mand is to be run, but an overdue command will execute at the
2606 next prompt. A command which comes due while the shell is
2607 waiting for user input is executed immediately. However, nor‐
2608 mal operation of an already-running command will not be inter‐
2609 rupted so that a scheduled-event list element may be run.
2610 This mechanism is similar to, but not the same as, the at(1)
2612 command on some Unix systems. Its major disadvantage is that
2613 it may not run a command at exactly the specified time. Its
2614 major advantage is that because sched runs directly from the
2615 shell, it has access to shell variables and other structures.
2616 This provides a mechanism for changing one's working environ‐
2617 ment based on the time of day.
2618 set
2620 set name ...
2621 set name=word ...
2622 set [-r] [-f|-l] name=(wordlist) ... (+)
2623 set name[index]=word ...
2624 set -r (+)
2625 set -r name ... (+)
2626 set -r name=word ... (+)
2627 The first form of the command prints the value of all shell
2628 variables. Variables which contain more than a single word
2629 print as a parenthesized word list. The second form sets name
2630 to the null string. The third form sets name to the single
2631 word. The fourth form sets name to the list of words in
2632 wordlist. In all cases the value is command and filename
2633 expanded. If -r is specified, the value is set read-only. If
2634 -f or -l are specified, set only unique words keeping their
2635 order. -f prefers the first occurrence of a word, and -l the
2636 last. The fifth form sets the index'th component of name to
2637 word; this component must already exist. The sixth form lists
2638 only the names of all shell variables that are read-only. The
2639 seventh form makes name read-only, whether or not it has a
2640 value. The eighth form is the same as the third form, but make
2641 name read-only at the same time.
2642 These arguments can be repeated to set and/or make read-only
2644 multiple variables in a single set command. Note, however,
2645 that variable expansion happens for all arguments before any
2646 setting occurs. Note also that `=' can be adjacent to both
2647 name and word or separated from both by whitespace, but cannot
2648 be adjacent to only one or the other. See also the unset
2649 builtin command.
2650 setenv [name [value]]
2652 Without arguments, prints the names and values of all environ‐
2653 ment variables. Given name, sets the environment variable name
2654 to value or, without value, to the null string.
2655 setpath path (+)
2657 Equivalent to setpath(1). (Mach only)
2658 setspath LOCAL|site|cpu ... (+)
2660 Sets the system execution path. (TCF only)
2661 settc cap value (+)
2663 Tells the shell to believe that the terminal capability cap (as
2664 defined in termcap(5)) has the value value. No sanity checking
2665 is done. Concept terminal users may have to `settc xn no' to
2666 get proper wrapping at the rightmost column.
2667 setty [-d|-q|-x] [-a] [[+|-]mode] (+)
2669 Controls which tty modes (see Terminal management) the shell
2670 does not allow to change. -d, -q or -x tells setty to act on
2671 the `edit', `quote' or `execute' set of tty modes respectively;
2672 without -d, -q or -x, `execute' is used.
2673 Without other arguments, setty lists the modes in the chosen
2675 set which are fixed on (`+mode') or off (`-mode'). The avail‐
2676 able modes, and thus the display, vary from system to system.
2677 With -a, lists all tty modes in the chosen set whether or not
2678 they are fixed. With +mode, -mode or mode, fixes mode on or
2679 off or removes control from mode in the chosen set. For exam‐
2680 ple, `setty +echok echoe' fixes `echok' mode on and allows com‐
2681 mands to turn `echoe' mode on or off, both when the shell is
2682 executing commands.
2683 setxvers [string] (+)
2685 Set the experimental version prefix to string, or removes it if
2686 string is omitted. (TCF only)
2687 shift [variable]
2689 Without arguments, discards argv[1] and shifts the members of
2690 argv to the left. It is an error for argv not to be set or to
2691 have less than one word as value. With variable, performs the
2692 same function on variable.
2693 source [-h] name [args ...]
2695 The shell reads and executes commands from name. The commands
2696 are not placed on the history list. If any args are given,
2697 they are placed in argv. (+) source commands may be nested; if
2698 they are nested too deeply the shell may run out of file
2699 descriptors. An error in a source at any level terminates all
2700 nested source commands. With -h, commands are placed on the
2701 history list instead of being executed, much like `history -L'.
2702 stop %job|pid ...
2704 Stops the specified jobs or processes which are executing in
2705 the background. job may be a number, a string, `', `%', `+' or
2706 `-' as described under Jobs. There is no default job; saying
2707 just `stop' does not stop the current job.
2708 suspend Causes the shell to stop in its tracks, much as if it had been
2710 sent a stop signal with ^Z. This is most often used to stop
2711 shells started by su(1).
2712 switch (string)
2714 case str1:
2715 ...
2716 breaksw
2717 ...
2718 default:
2719 ...
2720 breaksw
2721 endsw Each case label is successively matched, against the specified
2722 string which is first command and filename expanded. The file
2723 metacharacters `*', `?' and `[...]' may be used in the case
2724 labels, which are variable expanded. If none of the labels
2725 match before a `default' label is found, then the execution
2726 begins after the default label. Each case label and the
2727 default label must appear at the beginning of a line. The com‐
2728 mand breaksw causes execution to continue after the endsw.
2729 Otherwise control may fall through case labels and default
2730 labels as in C. If no label matches and there is no default,
2731 execution continues after the endsw.
2732 telltc (+)
2734 Lists the values of all terminal capabilities (see termcap(5)).
2735 termname [terminal type] (+)
2737 Tests if terminal type (or the current value of TERM if no ter‐
2738 minal type is given) has an entry in the hosts termcap(5) or
2739 terminfo(5) database. Prints the terminal type to stdout and
2740 returns 0 if an entry is present otherwise returns 1.
2741 time [command]
2743 Executes command (which must be a simple command, not an alias,
2744 a pipeline, a command list or a parenthesized command list) and
2745 prints a time summary as described under the time variable. If
2746 necessary, an extra shell is created to print the time statis‐
2747 tic when the command completes. Without command, prints a time
2748 summary for the current shell and its children.
2749 umask [value]
2751 Sets the file creation mask to value, which is given in octal.
2752 Common values for the mask are 002, giving all access to the
2753 group and read and execute access to others, and 022, giving
2754 read and execute access to the group and others. Without
2755 value, prints the current file creation mask.
2756 unalias pattern
2758 Removes all aliases whose names match pattern. `unalias *'
2759 thus removes all aliases. It is not an error for nothing to be
2760 unaliased.
2761 uncomplete pattern (+)
2763 Removes all completions whose names match pattern. `uncomplete
2764 *' thus removes all completions. It is not an error for noth‐
2765 ing to be uncompleted.
2766 unhash Disables use of the internal hash table to speed location of
2768 executed programs.
2769 universe universe (+)
2771 Sets the universe to universe. (Masscomp/RTU only)
2772 unlimit [-hf] [resource]
2774 Removes the limitation on resource or, if no resource is speci‐
2775 fied, all resource limitations. With -h, the corresponding
2776 hard limits are removed. Only the super-user may do this.
2777 Note that unlimit may not exit successful, since most systems
2778 do not allow descriptors to be unlimited. With -f errors are
2779 ignored.
2780 unset pattern
2782 Removes all variables whose names match pattern, unless they
2783 are read-only. `unset *' thus removes all variables unless
2784 they are read-only; this is a bad idea. It is not an error for
2785 nothing to be unset.
2786 unsetenv pattern
2788 Removes all environment variables whose names match pattern.
2789 `unsetenv *' thus removes all environment variables; this is a
2790 bad idea. It is not an error for nothing to be unsetenved.
2791 ver [systype [command]] (+)
2793 Without arguments, prints SYSTYPE. With systype, sets SYSTYPE
2794 to systype. With systype and command, executes command under
2795 systype. systype may be `bsd4.3' or `sys5.3'. (Domain/OS
2796 only)
2797 wait The shell waits for all background jobs. If the shell is
2799 interactive, an interrupt will disrupt the wait and cause the
2800 shell to print the names and job numbers of all outstanding
2801 jobs.
2802 warp universe (+)
2804 Sets the universe to universe. (Convex/OS only)
2805 watchlog (+)
2807 An alternate name for the log builtin command (q.v.). Avail‐
2808 able only if the shell was so compiled; see the version shell
2809 variable.
2810 where command (+)
2812 Reports all known instances of command, including aliases,
2813 builtins and executables in path.
2814 which command (+)
2816 Displays the command that will be executed by the shell after
2817 substitutions, path searching, etc. The builtin command is
2818 just like which(1), but it correctly reports tcsh aliases and
2819 builtins and is 10 to 100 times faster. See also the which-
2820 command editor command.
2821 while (expr)
2823 ...
2824 end Executes the commands between the while and the matching end
2825 while expr (an expression, as described under Expressions)
2826 evaluates non-zero. while and end must appear alone on their
2827 input lines. break and continue may be used to terminate or
2828 continue the loop prematurely. If the input is a terminal, the
2829 user is prompted the first time through the loop as with fore‐
2830 ach.
2831 Special aliases (+)
2833 If set, each of these aliases executes automatically at the indicated
2834 time. They are all initially undefined.
2835 beepcmd Runs when the shell wants to ring the terminal bell.
2837 cwdcmd Runs after every change of working directory. For example, if
2839 the user is working on an X window system using xterm(1) and a
2840 re-parenting window manager that supports title bars such as
2841 twm(1) and does
2842 > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd ^G"'
2844 then the shell will change the title of the running xterm(1) to
2846 be the name of the host, a colon, and the full current working
2847 directory. A fancier way to do that is
2848 > alias cwdcmd 'echo -n
2850 "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'
2851 This will put the hostname and working directory on the title
2853 bar but only the hostname in the icon manager menu.
2854 Note that putting a cd, pushd or popd in cwdcmd may cause an
2856 infinite loop. It is the author's opinion that anyone doing so
2857 will get what they deserve.
2858 jobcmd Runs before each command gets executed, or when the command
2860 changes state. This is similar to postcmd, but it does not
2861 print builtins.
2862 > alias jobcmd 'echo -n "^[]2\;\!#:q^G"'
2864 then executing vi foo.c will put the command string in the
2866 xterm title bar.
2867 helpcommand
2869 Invoked by the run-help editor command. The command name for
2870 which help is sought is passed as sole argument. For example,
2871 if one does
2872 > alias helpcommand '\!:1 --help'
2874 then the help display of the command itself will be invoked,
2876 using the GNU help calling convention. Currently there is no
2877 easy way to account for various calling conventions (e.g., the
2878 customary Unix `-h'), except by using a table of many commands.
2879 periodic
2881 Runs every tperiod minutes. This provides a convenient means
2882 for checking on common but infrequent changes such as new mail.
2883 For example, if one does
2884 > set tperiod = 30
2886 > alias periodic checknews
2887 then the checknews(1) program runs every 30 minutes. If peri‐
2889 odic is set but tperiod is unset or set to 0, periodic behaves
2890 like precmd.
2891 precmd Runs just before each prompt is printed. For example, if one
2893 does
2894 > alias precmd date
2896 then date(1) runs just before the shell prompts for each com‐
2898 mand. There are no limits on what precmd can be set to do, but
2899 discretion should be used.
2900 postcmd Runs before each command gets executed.
2902 > alias postcmd 'echo -n "^[]2\;\!#:q^G"'
2904 then executing vi foo.c will put the command string in the
2906 xterm title bar.
2907 shell Specifies the interpreter for executable scripts which do not
2909 themselves specify an interpreter. The first word should be a
2910 full path name to the desired interpreter (e.g., `/bin/csh' or
2911 `/usr/local/bin/tcsh').
2912 Special shell variables
2914 The variables described in this section have special meaning to the
2915 shell.
2916 The shell sets addsuffix, argv, autologout, csubstnonl, command,
2918 echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
2919 prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
2920 at startup; they do not change thereafter unless changed by the user.
2921 The shell updates cwd, dirstack, owd and status when necessary, and
2922 sets logout on logout.
2923 The shell synchronizes group, home, path, shlvl, term and user with the
2925 environment variables of the same names: whenever the environment vari‐
2926 able changes the shell changes the corresponding shell variable to
2927 match (unless the shell variable is read-only) and vice versa. Note
2928 that although cwd and PWD have identical meanings, they are not syn‐
2929 chronized in this manner, and that the shell automatically intercon‐
2930 verts the different formats of path and PATH.
2931 addsuffix (+)
2933 If set, filename completion adds `/' to the end of directories
2934 and a space to the end of normal files when they are matched
2935 exactly. Set by default.
2936 afsuser (+)
2938 If set, autologout's autolock feature uses its value instead of
2939 the local username for kerberos authentication.
2940 ampm (+)
2942 If set, all times are shown in 12-hour AM/PM format.
2943 argv The arguments to the shell. Positional parameters are taken
2945 from argv, i.e., `$1' is replaced by `$argv[1]', etc. Set by
2946 default, but usually empty in interactive shells.
2947 autocorrect (+)
2949 If set, the spell-word editor command is invoked automatically
2950 before each completion attempt.
2951 autoexpand (+)
2953 If set, the expand-history editor command is invoked automati‐
2954 cally before each completion attempt. If this is set to only‐
2955 history, then only history will be expanded and a second com‐
2956 pletion will expand filenames.
2957 autolist (+)
2959 If set, possibilities are listed after an ambiguous completion.
2960 If set to `ambiguous', possibilities are listed only when no
2961 new characters are added by completion.
2962 autologout (+)
2964 The first word is the number of minutes of inactivity before
2965 automatic logout. The optional second word is the number of
2966 minutes of inactivity before automatic locking. When the shell
2967 automatically logs out, it prints `auto-logout', sets the vari‐
2968 able logout to `automatic' and exits. When the shell automati‐
2969 cally locks, the user is required to enter his password to con‐
2970 tinue working. Five incorrect attempts result in automatic
2971 logout. Set to `60' (automatic logout after 60 minutes, and no
2972 locking) by default in login and superuser shells, but not if
2973 the shell thinks it is running under a window system (i.e., the
2974 DISPLAY environment variable is set), the tty is a pseudo-tty
2975 (pty) or the shell was not so compiled (see the version shell
2976 variable). See also the afsuser and logout shell variables.
2977 backslash_quote (+)
2979 If set, backslashes (`\') always quote `\', `'', and `"'. This
2980 may make complex quoting tasks easier, but it can cause syntax
2981 errors in csh(1) scripts.
2982 catalog The file name of the message catalog. If set, tcsh use
2984 `tcsh.${catalog}' as a message catalog instead of default
2985 `tcsh'.
2986 cdpath A list of directories in which cd should search for subdirecto‐
2988 ries if they aren't found in the current directory.
2989 color If set, it enables color display for the builtin ls-F and it
2991 passes --color=auto to ls. Alternatively, it can be set to
2992 only ls-F or only ls to enable color to only one command. Set‐
2993 ting it to nothing is equivalent to setting it to (ls-F ls).
2994 colorcat
2996 If set, it enables color escape sequence for NLS message files.
2997 And display colorful NLS messages.
2998 command (+)
3000 If set, the command which was passed to the shell with the -c
3001 flag (q.v.).
3002 compat_expr (+)
3004 If set, the shell will evaluate expressions right to left, like
3005 the original csh.
3006 complete (+)
3008 If set to `enhance', completion 1) ignores case and 2) consid‐
3009 ers periods, hyphens and underscores (`.', `-' and `_') to be
3010 word separators and hyphens and underscores to be equivalent.
3011 If set to `igncase', the completion becomes case insensitive.
3012 continue (+)
3014 If set to a list of commands, the shell will continue the
3015 listed commands, instead of starting a new one.
3016 continue_args (+)
3018 Same as continue, but the shell will execute:
3019 echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>
3021 correct (+)
3023 If set to `cmd', commands are automatically spelling-corrected.
3024 If set to `complete', commands are automatically completed. If
3025 set to `all', the entire command line is corrected.
3026 csubstnonl (+)
3028 If set, newlines and carriage returns in command substitution
3029 are replaced by spaces. Set by default.
3030 cwd The full pathname of the current directory. See also the
3032 dirstack and owd shell variables.
3033 dextract (+)
3035 If set, `pushd +n' extracts the nth directory from the direc‐
3036 tory stack rather than rotating it to the top.
3037 dirsfile (+)
3039 The default location in which `dirs -S' and `dirs -L' look for
3040 a history file. If unset, ~/.cshdirs is used. Because only
3041 ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
3042 should be set in ~/.tcshrc rather than ~/.login.
3043 dirstack (+)
3045 An array of all the directories on the directory stack.
3046 `$dirstack[1]' is the current working directory, `$dirstack[2]'
3047 the first directory on the stack, etc. Note that the current
3048 working directory is `$dirstack[1]' but `=0' in directory stack
3049 substitutions, etc. One can change the stack arbitrarily by
3050 setting dirstack, but the first element (the current working
3051 directory) is always correct. See also the cwd and owd shell
3052 variables.
3053 dspmbyte (+)
3055 Has an affect iff 'dspm' is listed as part of the version shell
3056 variable. If set to `euc', it enables display and editing EUC-
3057 kanji(Japanese) code. If set to `sjis', it enables display and
3058 editing Shift-JIS(Japanese) code. If set to `big5', it enables
3059 display and editing Big5(Chinese) code. If set to `utf8', it
3060 enables display and editing Utf8(Unicode) code. If set to the
3061 following format, it enables display and editing of original
3062 multi-byte code format:
3063 > set dspmbyte = 0000....(256 bytes)....0000
3065 The table requires just 256 bytes. Each character of 256 char‐
3067 acters corresponds (from left to right) to the ASCII codes
3068 0x00, 0x01, ... 0xff. Each character is set to number 0,1,2
3069 and 3. Each number has the following meaning:
3070 0 ... not used for multi-byte characters.
3071 1 ... used for the first byte of a multi-byte character.
3072 2 ... used for the second byte of a multi-byte character.
3073 3 ... used for both the first byte and second byte of a
3074 multi-byte character.
3075 Example:
3083 If set to `001322', the first character (means 0x00 of the
3084 ASCII code) and second character (means 0x01 of ASCII code) are
3085 set to `0'. Then, it is not used for multi-byte characters.
3086 The 3rd character (0x02) is set to '1', indicating that it is
3087 used for the first byte of a multi-byte character. The 4th
3088 character(0x03) is set '3'. It is used for both the first byte
3089 and the second byte of a multi-byte character. The 5th and 6th
3090 characters (0x04,0x05) are set to '2', indicating that they are
3091 used for the second byte of a multi-byte character.
3092 The GNU fileutils version of ls cannot display multi-byte file‐
3094 names without the -N ( --literal ) option. If you are using
3095 this version, set the second word of dspmbyte to "ls". If not,
3096 for example, "ls-F -l" cannot display multi-byte filenames.
3097 Note:
3099 This variable can only be used if KANJI and DSPMBYTE has been
3100 defined at compile time.
3101 dunique (+)
3103 If set, pushd removes any instances of name from the stack
3104 before pushing it onto the stack.
3105 echo If set, each command with its arguments is echoed just before
3107 it is executed. For non-builtin commands all expansions occur
3108 before echoing. Builtin commands are echoed before command and
3109 filename substitution, because these substitutions are then
3110 done selectively. Set by the -x command line option.
3111 echo_style (+)
3113 The style of the echo builtin. May be set to
3114 bsd Don't echo a newline if the first argument is `-n'.
3116 sysv Recognize backslashed escape sequences in echo strings.
3117 both Recognize both the `-n' flag and backslashed escape
3118 sequences; the default.
3119 none Recognize neither.
3120 Set by default to the local system default. The BSD and System
3122 V options are described in the echo(1) man pages on the appro‐
3123 priate systems.
3124 edit (+)
3126 If set, the command-line editor is used. Set by default in
3127 interactive shells.
3128 ellipsis (+)
3130 If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
3131 shell variable) indicate skipped directories with an ellipsis
3132 (`...') instead of `/<skipped>'.
3133 fignore (+)
3135 Lists file name suffixes to be ignored by completion.
3136 filec In tcsh, completion is always used and this variable is ignored
3138 by default. If edit is unset, then the traditional csh comple‐
3139 tion is used. If set in csh, filename completion is used.
3140 gid (+) The user's real group ID.
3142 group (+)
3144 The user's group name.
3145 highlight
3147 If set, the incremental search match (in i-search-back and i-
3148 search-fwd) and the region between the mark and the cursor are
3149 highlighted in reverse video.
3150 Highlighting requires more frequent terminal writes, which
3152 introduces extra overhead. If you care about terminal perfor‐
3153 mance, you may want to leave this unset.
3154 histchars
3156 A string value determining the characters used in History sub‐
3157 stitution (q.v.). The first character of its value is used as
3158 the history substitution character, replacing the default char‐
3159 acter `!'. The second character of its value replaces the
3160 character `^' in quick substitutions.
3161 histdup (+)
3163 Controls handling of duplicate entries in the history list. If
3164 set to `all' only unique history events are entered in the his‐
3165 tory list. If set to `prev' and the last history event is the
3166 same as the current command, then the current command is not
3167 entered in the history. If set to `erase' and the same event
3168 is found in the history list, that old event gets erased and
3169 the current one gets inserted. Note that the `prev' and `all'
3170 options renumber history events so there are no gaps.
3171 histfile (+)
3173 The default location in which `history -S' and `history -L'
3174 look for a history file. If unset, ~/.history is used. hist‐
3175 file is useful when sharing the same home directory between
3176 different machines, or when saving separate histories on dif‐
3177 ferent terminals. Because only ~/.tcshrc is normally sourced
3178 before ~/.history, histfile should be set in ~/.tcshrc rather
3179 than ~/.login.
3180 histlit (+)
3182 If set, builtin and editor commands and the savehist mechanism
3183 use the literal (unexpanded) form of lines in the history list.
3184 See also the toggle-literal-history editor command.
3185 history The first word indicates the number of history events to save.
3187 The optional second word (+) indicates the format in which his‐
3188 tory is printed; if not given, `%h\t%T\t%R\n' is used. The
3189 format sequences are described below under prompt; note the
3190 variable meaning of `%R'. Set to `100' by default.
3191 home Initialized to the home directory of the invoker. The filename
3193 expansion of `~' refers to this variable.
3194 ignoreeof
3196 If set to the empty string or `0' and the input device is a
3197 terminal, the end-of-file command (usually generated by the
3198 user by typing `^D' on an empty line) causes the shell to print
3199 `Use "exit" to leave tcsh.' instead of exiting. This prevents
3200 the shell from accidentally being killed. Historically this
3201 setting exited after 26 successive EOF's to avoid infinite
3202 loops. If set to a number n, the shell ignores n - 1 consecu‐
3203 tive end-of-files and exits on the nth. (+) If unset, `1' is
3204 used, i.e., the shell exits on a single `^D'.
3205 implicitcd (+)
3207 If set, the shell treats a directory name typed as a command as
3208 though it were a request to change to that directory. If set
3209 to verbose, the change of directory is echoed to the standard
3210 output. This behavior is inhibited in non-interactive shell
3211 scripts, or for command strings with more than one word.
3212 Changing directory takes precedence over executing a like-named
3213 command, but it is done after alias substitutions. Tilde and
3214 variable expansions work as expected.
3215 inputmode (+)
3217 If set to `insert' or `overwrite', puts the editor into that
3218 input mode at the beginning of each line.
3219 killdup (+)
3221 Controls handling of duplicate entries in the kill ring. If
3222 set to `all' only unique strings are entered in the kill ring.
3223 If set to `prev' and the last killed string is the same as the
3224 current killed string, then the current string is not entered
3225 in the ring. If set to `erase' and the same string is found in
3226 the kill ring, the old string is erased and the current one is
3227 inserted.
3228 killring (+)
3230 Indicates the number of killed strings to keep in memory. Set
3231 to `30' by default. If unset or set to less than `2', the
3232 shell will only keep the most recently killed string. Strings
3233 are put in the killring by the editor commands that delete
3234 (kill) strings of text, e.g. backward-delete-word, kill-line,
3235 etc, as well as the copy-region-as-kill command. The yank edi‐
3236 tor command will yank the most recently killed string into the
3237 command-line, while yank-pop (see Editor commands) can be used
3238 to yank earlier killed strings.
3239 listflags (+)
3241 If set to `x', `a' or `A', or any combination thereof (e.g.,
3242 `xA'), they are used as flags to ls-F, making it act like `ls
3243 -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
3244 `a' shows all files (even if they start with a `.'), `A' shows
3245 all files but `.' and `..', and `x' sorts across instead of
3246 down. If the second word of listflags is set, it is used as
3247 the path to `ls(1)'.
3248 listjobs (+)
3250 If set, all jobs are listed when a job is suspended. If set to
3251 `long', the listing is in long format.
3252 listlinks (+)
3254 If set, the ls-F builtin command shows the type of file to
3255 which each symbolic link points.
3256 listmax (+)
3258 The maximum number of items which the list-choices editor com‐
3259 mand will list without asking first.
3260 listmaxrows (+)
3262 The maximum number of rows of items which the list-choices edi‐
3263 tor command will list without asking first.
3264 loginsh (+)
3266 Set by the shell if it is a login shell. Setting or unsetting
3267 it within a shell has no effect. See also shlvl.
3268 logout (+)
3270 Set by the shell to `normal' before a normal logout, `auto‐
3271 matic' before an automatic logout, and `hangup' if the shell
3272 was killed by a hangup signal (see Signal handling). See also
3273 the autologout shell variable.
3274 mail The names of the files or directories to check for incoming
3276 mail, separated by whitespace, and optionally preceded by a
3277 numeric word. Before each prompt, if 10 minutes have passed
3278 since the last check, the shell checks each file and says `You
3279 have new mail.' (or, if mail contains multiple files, `You have
3280 new mail in name.') if the filesize is greater than zero in
3281 size and has a modification time greater than its access time.
3282 If you are in a login shell, then no mail file is reported
3284 unless it has been modified after the time the shell has
3285 started up, to prevent redundant notifications. Most login
3286 programs will tell you whether or not you have mail when you
3287 log in.
3288 If a file specified in mail is a directory, the shell will
3290 count each file within that directory as a separate message,
3291 and will report `You have n mails.' or `You have n mails in
3292 name.' as appropriate. This functionality is provided primar‐
3293 ily for those systems which store mail in this manner, such as
3294 the Andrew Mail System.
3295 If the first word of mail is numeric it is taken as a different
3297 mail checking interval, in seconds.
3298 Under very rare circumstances, the shell may report `You have
3300 mail.' instead of `You have new mail.'
3301 matchbeep (+)
3303 If set to `never', completion never beeps. If set to
3304 `nomatch', it beeps only when there is no match. If set to
3305 `ambiguous', it beeps when there are multiple matches. If set
3306 to `notunique', it beeps when there is one exact and other
3307 longer matches. If unset, `ambiguous' is used.
3308 nobeep (+)
3310 If set, beeping is completely disabled. See also visiblebell.
3311 noclobber
3313 If set, restrictions are placed on output redirection to insure
3314 that files are not accidentally destroyed and that `>>' redi‐
3315 rections refer to existing files, as described in the
3316 Input/output section.
3317 noding If set, disable the printing of `DING!' in the prompt time
3319 specifiers at the change of hour.
3320 noglob If set, Filename substitution and Directory stack substitution
3322 (q.v.) are inhibited. This is most useful in shell scripts
3323 which do not deal with filenames, or after a list of filenames
3324 has been obtained and further expansions are not desirable.
3325 nokanji (+)
3327 If set and the shell supports Kanji (see the version shell
3328 variable), it is disabled so that the meta key can be used.
3329 nonomatch
3331 If set, a Filename substitution or Directory stack substitution
3332 (q.v.) which does not match any existing files is left
3333 untouched rather than causing an error. It is still an error
3334 for the substitution to be malformed, e.g., `echo [' still
3335 gives an error.
3336 nostat (+)
3338 A list of directories (or glob-patterns which match directo‐
3339 ries; see Filename substitution) that should not be stat(2)ed
3340 during a completion operation. This is usually used to exclude
3341 directories which take too much time to stat(2), for example
3342 /afs.
3343 notify If set, the shell announces job completions asynchronously.
3345 The default is to present job completions just before printing
3346 a prompt.
3347 oid (+) The user's real organization ID. (Domain/OS only)
3349 owd (+) The old working directory, equivalent to the `-' used by cd and
3351 pushd. See also the cwd and dirstack shell variables.
3352 padhour If set, enable the printing of padding '0' for hours, in 24 and
3354 12 hour formats. E.G.: 07:45:42 vs. 7:45:42
3355 path A list of directories in which to look for executable commands.
3357 A null word specifies the current directory. If there is no
3358 path variable then only full path names will execute. path is
3359 set by the shell at startup from the PATH environment variable
3360 or, if PATH does not exist, to a system-dependent default some‐
3361 thing like `(/usr/local/bin /usr/bsd /bin /usr/bin .)'. The
3362 shell may put `.' first or last in path or omit it entirely
3363 depending on how it was compiled; see the version shell vari‐
3364 able. A shell which is given neither the -c nor the -t option
3365 hashes the contents of the directories in path after reading
3366 ~/.tcshrc and each time path is reset. If one adds a new com‐
3367 mand to a directory in path while the shell is active, one may
3368 need to do a rehash for the shell to find it.
3369 printexitvalue (+)
3371 If set and an interactive program exits with a non-zero status,
3372 the shell prints `Exit status'.
3373 prompt The string which is printed before reading each command from
3375 the terminal. prompt may include any of the following format‐
3376 ting sequences (+), which are replaced by the given informa‐
3377 tion:
3378 %/ The current working directory.
3380 %~ The current working directory, but with one's home direc‐
3381 tory represented by `~' and other users' home directories
3382 represented by `~user' as per Filename substitution.
3383 `~user' substitution happens only if the shell has already
3384 used `~user' in a pathname in the current session.
3385 %c[[0]n], %.[[0]n]
3386 The trailing component of the current working directory, or
3387 n trailing components if a digit n is given. If n begins
3388 with `0', the number of skipped components precede the
3389 trailing component(s) in the format `/<skipped>trailing'.
3390 If the ellipsis shell variable is set, skipped components
3391 are represented by an ellipsis so the whole becomes
3392 `...trailing'. `~' substitution is done as in `%~' above,
3393 but the `~' component is ignored when counting trailing
3394 components.
3395 %C Like %c, but without `~' substitution.
3396 %h, %!, !
3397 The current history event number.
3398 %M The full hostname.
3399 %m The hostname up to the first `.'.
3400 %S (%s)
3401 Start (stop) standout mode.
3402 %B (%b)
3403 Start (stop) boldfacing mode.
3404 %U (%u)
3405 Start (stop) underline mode.
3406 %t, %@
3407 The time of day in 12-hour AM/PM format.
3408 %T Like `%t', but in 24-hour format (but see the ampm shell
3409 variable).
3410 %p The `precise' time of day in 12-hour AM/PM format, with
3411 seconds.
3412 %P Like `%p', but in 24-hour format (but see the ampm shell
3413 variable).
3414 \c c is parsed as in bindkey.
3415 ^c c is parsed as in bindkey.
3416 %% A single `%'.
3417 %n The user name.
3418 %j The number of jobs.
3419 %d The weekday in `Day' format.
3420 %D The day in `dd' format.
3421 %w The month in `Mon' format.
3422 %W The month in `mm' format.
3423 %y The year in `yy' format.
3424 %Y The year in `yyyy' format.
3425 %l The shell's tty.
3426 %L Clears from the end of the prompt to end of the display or
3427 the end of the line.
3428 %$ Expands the shell or environment variable name immediately
3429 after the `$'.
3430 %# `>' (or the first character of the promptchars shell vari‐
3431 able) for normal users, `#' (or the second character of
3432 promptchars) for the superuser.
3433 %{string%}
3434 Includes string as a literal escape sequence. It should be
3435 used only to change terminal attributes and should not move
3436 the cursor location. This cannot be the last sequence in
3437 prompt.
3438 %? The return code of the command executed just before the
3439 prompt.
3440 %R In prompt2, the status of the parser. In prompt3, the cor‐
3441 rected string. In history, the history string.
3442 `%B', `%S', `%U' and `%{string%}' are available in only eight-
3444 bit-clean shells; see the version shell variable.
3445 The bold, standout and underline sequences are often used to
3447 distinguish a superuser shell. For example,
3448 > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
3450 tut [37] [2:54pm] [/usr/accts/sys] you rang? _
3451 If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
3453 set, then print `DING!' on the change of hour (i.e, `:00' min‐
3454 utes) instead of the actual time.
3455 Set by default to `%# ' in interactive shells.
3457 prompt2 (+)
3459 The string with which to prompt in while and foreach loops and
3460 after lines ending in `\'. The same format sequences may be
3461 used as in prompt (q.v.); note the variable meaning of `%R'.
3462 Set by default to `%R? ' in interactive shells.
3463 prompt3 (+)
3465 The string with which to prompt when confirming automatic
3466 spelling correction. The same format sequences may be used as
3467 in prompt (q.v.); note the variable meaning of `%R'. Set by
3468 default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.
3469 promptchars (+)
3471 If set (to a two-character string), the `%#' formatting
3472 sequence in the prompt shell variable is replaced with the
3473 first character for normal users and the second character for
3474 the superuser.
3475 pushdtohome (+)
3477 If set, pushd without arguments does `pushd ~', like cd.
3478 pushdsilent (+)
3480 If set, pushd and popd do not print the directory stack.
3481 recexact (+)
3483 If set, completion completes on an exact match even if a longer
3484 match is possible.
3485 recognize_only_executables (+)
3487 If set, command listing displays only files in the path that
3488 are executable. Slow.
3489 rmstar (+)
3491 If set, the user is prompted before `rm *' is executed.
3492 rprompt (+)
3494 The string to print on the right-hand side of the screen (after
3495 the command input) when the prompt is being displayed on the
3496 left. It recognizes the same formatting characters as prompt.
3497 It will automatically disappear and reappear as necessary, to
3498 ensure that command input isn't obscured, and will appear only
3499 if the prompt, command input, and itself will fit together on
3500 the first line. If edit isn't set, then rprompt will be
3501 printed after the prompt and before the command input.
3502 savedirs (+)
3504 If set, the shell does `dirs -S' before exiting. If the first
3505 word is set to a number, at most that many directory stack
3506 entries are saved.
3507 savehist
3509 If set, the shell does `history -S' before exiting. If the
3510 first word is set to a number, at most that many lines are
3511 saved. (The number must be less than or equal to history.) If
3512 the second word is set to `merge', the history list is merged
3513 with the existing history file instead of replacing it (if
3514 there is one) and sorted by time stamp and the most recent
3515 events are retained. (+)
3516 sched (+)
3518 The format in which the sched builtin command prints scheduled
3519 events; if not given, `%h\t%T\t%R\n' is used. The format
3520 sequences are described above under prompt; note the variable
3521 meaning of `%R'.
3522 shell The file in which the shell resides. This is used in forking
3524 shells to interpret files which have execute bits set, but
3525 which are not executable by the system. (See the description
3526 of Builtin and non-builtin command execution.) Initialized to
3527 the (system-dependent) home of the shell.
3528 shlvl (+)
3530 The number of nested shells. Reset to 1 in login shells. See
3531 also loginsh.
3532 status The status returned by the last command. If it terminated
3534 abnormally, then 0200 is added to the status. Builtin commands
3535 which fail return exit status `1', all other builtin commands
3536 return status `0'.
3537 symlinks (+)
3539 Can be set to several different values to control symbolic link
3540 (`symlink') resolution:
3541 If set to `chase', whenever the current directory changes to a
3543 directory containing a symbolic link, it is expanded to the
3544 real name of the directory to which the link points. This does
3545 not work for the user's home directory; this is a bug.
3546 If set to `ignore', the shell tries to construct a current
3548 directory relative to the current directory before the link was
3549 crossed. This means that cding through a symbolic link and
3550 then `cd ..'ing returns one to the original directory. This
3551 affects only builtin commands and filename completion.
3552 If set to `expand', the shell tries to fix symbolic links by
3554 actually expanding arguments which look like path names. This
3555 affects any command, not just builtins. Unfortunately, this
3556 does not work for hard-to-recognize filenames, such as those
3557 embedded in command options. Expansion may be prevented by
3558 quoting. While this setting is usually the most convenient, it
3559 is sometimes misleading and sometimes confusing when it fails
3560 to recognize an argument which should be expanded. A compro‐
3561 mise is to use `ignore' and use the editor command normalize-
3562 path (bound by default to ^X-n) when necessary.
3563 Some examples are in order. First, let's set up some play
3565 directories:
3566 > cd /tmp
3568 > mkdir from from/src to
3569 > ln -s from/src to/dst
3570 Here's the behavior with symlinks unset,
3572 > cd /tmp/to/dst; echo $cwd
3574 /tmp/to/dst
3575 > cd ..; echo $cwd
3576 /tmp/from
3577 here's the behavior with symlinks set to `chase',
3579 > cd /tmp/to/dst; echo $cwd
3581 /tmp/from/src
3582 > cd ..; echo $cwd
3583 /tmp/from
3584 here's the behavior with symlinks set to `ignore',
3586 > cd /tmp/to/dst; echo $cwd
3588 /tmp/to/dst
3589 > cd ..; echo $cwd
3590 /tmp/to
3591 and here's the behavior with symlinks set to `expand'.
3593 > cd /tmp/to/dst; echo $cwd
3595 /tmp/to/dst
3596 > cd ..; echo $cwd
3597 /tmp/to
3598 > cd /tmp/to/dst; echo $cwd
3599 /tmp/to/dst
3600 > cd ".."; echo $cwd
3601 /tmp/from
3602 > /bin/echo ..
3603 /tmp/to
3604 > /bin/echo ".."
3605 ..
3606 Note that `expand' expansion 1) works just like `ignore' for
3608 builtins like cd, 2) is prevented by quoting, and 3) happens
3609 before filenames are passed to non-builtin commands.
3610 tcsh (+)
3612 The version number of the shell in the format `R.VV.PP', where
3613 `R' is the major release number, `VV' the current version and
3614 `PP' the patchlevel.
3615 term The terminal type. Usually set in ~/.login as described under
3617 Startup and shutdown.
3618 time If set to a number, then the time builtin (q.v.) executes auto‐
3620 matically after each command which takes more than that many
3621 CPU seconds. If there is a second word, it is used as a format
3622 string for the output of the time builtin. (u) The following
3623 sequences may be used in the format string:
3624 %U The time the process spent in user mode in cpu seconds.
3626 %S The time the process spent in kernel mode in cpu seconds.
3627 %E The elapsed (wall clock) time in seconds.
3628 %P The CPU percentage computed as (%U + %S) / %E.
3629 %W Number of times the process was swapped.
3630 %X The average amount in (shared) text space used in Kbytes.
3631 %D The average amount in (unshared) data/stack space used in
3632 Kbytes.
3633 %K The total space used (%X + %D) in Kbytes.
3634 %M The maximum memory the process had in use at any time in
3635 Kbytes.
3636 %F The number of major page faults (page needed to be brought
3637 from disk).
3638 %R The number of minor page faults.
3639 %I The number of input operations.
3640 %O The number of output operations.
3641 %r The number of socket messages received.
3642 %s The number of socket messages sent.
3643 %k The number of signals received.
3644 %w The number of voluntary context switches (waits).
3645 %c The number of involuntary context switches.
3646 Only the first four sequences are supported on systems without
3648 BSD resource limit functions. The default time format is `%Uu
3649 %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
3650 resource usage reporting and `%Uu %Ss %E %P' for systems that
3651 do not.
3652 Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail‐
3654 able, but the following additional sequences are:
3655 %Y The number of system calls performed.
3657 %Z The number of pages which are zero-filled on demand.
3658 %i The number of times a process's resident set size was
3659 increased by the kernel.
3660 %d The number of times a process's resident set size was
3661 decreased by the kernel.
3662 %l The number of read system calls performed.
3663 %m The number of write system calls performed.
3664 %p The number of reads from raw disk devices.
3665 %q The number of writes to raw disk devices.
3666 and the default time format is `%Uu %Ss %E %P %I+%Oio
3668 %Fpf+%Ww'. Note that the CPU percentage can be higher than
3669 100% on multi-processors.
3670 tperiod (+)
3672 The period, in minutes, between executions of the periodic spe‐
3673 cial alias.
3674 tty (+) The name of the tty, or empty if not attached to one.
3676 uid (+) The user's real user ID.
3678 user The user's login name.
3680 verbose If set, causes the words of each command to be printed, after
3682 history substitution (if any). Set by the -v command line
3683 option.
3684 version (+)
3686 The version ID stamp. It contains the shell's version number
3687 (see tcsh), origin, release date, vendor, operating system and
3688 machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
3689 list of options which were set at compile time. Options which
3690 are set by default in the distribution are noted.
3691 8b The shell is eight bit clean; default
3693 7b The shell is not eight bit clean
3694 wide The shell is multibyte encoding clean (like UTF-8)
3695 nls The system's NLS is used; default for systems with NLS
3696 lf Login shells execute /etc/csh.login before instead of
3697 after /etc/csh.cshrc and ~/.login before instead of after
3698 ~/.tcshrc and ~/.history.
3699 dl `.' is put last in path for security; default
3700 nd `.' is omitted from path for security
3701 vi vi-style editing is the default rather than emacs
3702 dtr Login shells drop DTR when exiting
3703 bye bye is a synonym for logout and log is an alternate name
3704 for watchlog
3705 al autologout is enabled; default
3706 kan Kanji is used if appropriate according to locale set‐
3707 tings, unless the nokanji shell variable is set
3708 sm The system's malloc(3) is used
3709 hb The `#!<program> <args>' convention is emulated when exe‐
3710 cuting shell scripts
3711 ng The newgrp builtin is available
3712 rh The shell attempts to set the REMOTEHOST environment
3713 variable
3714 afs The shell verifies your password with the kerberos server
3715 if local authentication fails. The afsuser shell vari‐
3716 able or the AFSUSER environment variable override your
3717 local username if set.
3718 An administrator may enter additional strings to indicate dif‐
3720 ferences in the local version.
3721 visiblebell (+)
3723 If set, a screen flash is used rather than the audible bell.
3724 See also nobeep.
3725 watch (+)
3727 A list of user/terminal pairs to watch for logins and logouts.
3728 If either the user is `any' all terminals are watched for the
3729 given user and vice versa. Setting watch to `(any any)'
3730 watches all users and terminals. For example,
3731 set watch = (george ttyd1 any console $user any)
3733 reports activity of the user `george' on ttyd1, any user on the
3735 console, and oneself (or a trespasser) on any terminal.
3736 Logins and logouts are checked every 10 minutes by default, but
3738 the first word of watch can be set to a number to check every
3739 so many minutes. For example,
3740 set watch = (1 any any)
3742 reports any login/logout once every minute. For the impatient,
3744 the log builtin command triggers a watch report at any time.
3745 All current logins are reported (as with the log builtin) when
3746 watch is first set.
3747 The who shell variable controls the format of watch reports.
3749 who (+) The format string for watch messages. The following sequences
3751 are replaced by the given information:
3752 %n The name of the user who logged in/out.
3754 %a The observed action, i.e., `logged on', `logged off' or
3755 `replaced olduser on'.
3756 %l The terminal (tty) on which the user logged in/out.
3757 %M The full hostname of the remote host, or `local' if the
3758 login/logout was from the local host.
3759 %m The hostname of the remote host up to the first `.'. The
3760 full name is printed if it is an IP address or an X Window
3761 System display.
3762 %M and %m are available on only systems that store the remote
3764 hostname in /etc/utmp. If unset, `%n has %a %l from %m.' is
3765 used, or `%n has %a %l.' on systems which don't store the
3766 remote hostname.
3767 wordchars (+)
3769 A list of non-alphanumeric characters to be considered part of
3770 a word by the forward-word, backward-word etc., editor com‐
3771 mands. If unset, `*?_-.[]~=' is used.
3772
3774 AFSUSER (+)
3775 Equivalent to the afsuser shell variable.
3776 COLUMNS The number of columns in the terminal. See Terminal manage‐
3778 ment.
3779 DISPLAY Used by X Window System (see X(1)). If set, the shell does not
3781 set autologout (q.v.).
3782 EDITOR The pathname to a default editor. See also the VISUAL environ‐
3784 ment variable and the run-fg-editor editor command.
3785 GROUP (+)
3787 Equivalent to the group shell variable.
3788 HOME Equivalent to the home shell variable.
3790 HOST (+)
3792 Initialized to the name of the machine on which the shell is
3793 running, as determined by the gethostname(2) system call.
3794 HOSTTYPE (+)
3796 Initialized to the type of machine on which the shell is run‐
3797 ning, as determined at compile time. This variable is obsolete
3798 and will be removed in a future version.
3799 HPATH (+)
3801 A colon-separated list of directories in which the run-help
3802 editor command looks for command documentation.
3803 LANG Gives the preferred character environment. See Native Language
3805 System support.
3806 LC_CTYPE
3808 If set, only ctype character handling is changed. See Native
3809 Language System support.
3810 LINES The number of lines in the terminal. See Terminal management.
3812 LS_COLORS
3814 The format of this variable is reminiscent of the termcap(5)
3815 file format; a colon-separated list of expressions of the form
3816 "xx=string", where "xx" is a two-character variable name. The
3817 variables with their associated defaults are:
3818 no 0 Normal (non-filename) text
3820 fi 0 Regular file
3821 di 01;34 Directory
3822 ln 01;36 Symbolic link
3823 pi 33 Named pipe (FIFO)
3824 so 01;35 Socket
3825 do 01;35 Door
3826 bd 01;33 Block device
3827 cd 01;32 Character device
3828 ex 01;32 Executable file
3829 mi (none) Missing file (defaults to fi)
3830 or (none) Orphaned symbolic link (defaults to ln)
3831 lc ^[[ Left code
3832 rc m Right code
3833 ec (none) End code (replaces lc+no+rc)
3834 You need to include only the variables you want to change from
3836 the default.
3837 File names can also be colorized based on filename extension.
3839 This is specified in the LS_COLORS variable using the syntax
3840 "*ext=string". For example, using ISO 6429 codes, to color all
3841 C-language source files blue you would specify "*.c=34". This
3842 would color all files ending in .c in blue (34) color.
3843 Control characters can be written either in C-style-escaped
3845 notation, or in stty-like ^-notation. The C-style notation
3846 adds ^[ for Escape, _ for a normal space character, and ? for
3847 Delete. In addition, the ^[ escape character can be used to
3848 override the default interpretation of ^[, ^, : and =.
3849 Each file will be written as <lc> <color-code> <rc> <filename>
3851 <ec>. If the <ec> code is undefined, the sequence <lc> <no>
3852 <rc> will be used instead. This is generally more convenient
3853 to use, but less general. The left, right and end codes are
3854 provided so you don't have to type common parts over and over
3855 again and to support weird terminals; you will generally not
3856 need to change them at all unless your terminal does not use
3857 ISO 6429 color sequences but a different system.
3858 If your terminal does use ISO 6429 color codes, you can compose
3860 the type codes (i.e., all except the lc, rc, and ec codes) from
3861 numerical commands separated by semicolons. The most common
3862 commands are:
3863 0 to restore default color
3865 1 for brighter colors
3866 4 for underlined text
3867 5 for flashing text
3868 30 for black foreground
3869 31 for red foreground
3870 32 for green foreground
3871 33 for yellow (or brown) foreground
3872 34 for blue foreground
3873 35 for purple foreground
3874 36 for cyan foreground
3875 37 for white (or gray) foreground
3876 40 for black background
3877 41 for red background
3878 42 for green background
3879 43 for yellow (or brown) background
3880 44 for blue background
3881 45 for purple background
3882 46 for cyan background
3883 47 for white (or gray) background
3884 Not all commands will work on all systems or display devices.
3886 A few terminal programs do not recognize the default end code
3888 properly. If all text gets colorized after you do a directory
3889 listing, try changing the no and fi codes from 0 to the numeri‐
3890 cal codes for your standard fore- and background colors.
3891 MACHTYPE (+)
3893 The machine type (microprocessor class or machine model), as
3894 determined at compile time.
3895 NOREBIND (+)
3897 If set, printable characters are not rebound to self-insert-
3898 command. See Native Language System support.
3899 OSTYPE (+)
3901 The operating system, as determined at compile time.
3902 PATH A colon-separated list of directories in which to look for exe‐
3904 cutables. Equivalent to the path shell variable, but in a dif‐
3905 ferent format.
3906 PWD (+) Equivalent to the cwd shell variable, but not synchronized to
3908 it; updated only after an actual directory change.
3909 REMOTEHOST (+)
3911 The host from which the user has logged in remotely, if this is
3912 the case and the shell is able to determine it. Set only if
3913 the shell was so compiled; see the version shell variable.
3914 SHLVL (+)
3916 Equivalent to the shlvl shell variable.
3917 SYSTYPE (+)
3919 The current system type. (Domain/OS only)
3920 TERM Equivalent to the term shell variable.
3922 TERMCAP The terminal capability string. See Terminal management.
3924 USER Equivalent to the user shell variable.
3926 VENDOR (+)
3928 The vendor, as determined at compile time.
3929 VISUAL The pathname to a default full-screen editor. See also the
3931 EDITOR environment variable and the run-fg-editor editor com‐
3932 mand.
3933
3935 /etc/csh.cshrc Read first by every shell. ConvexOS, Stellix and Intel
3936 use /etc/cshrc and NeXTs use /etc/cshrc.std. A/UX,
3937 AMIX, Cray and IRIX have no equivalent in csh(1), but
3938 read this file in tcsh anyway. Solaris 2.x does not
3939 have it either, but tcsh reads /etc/.cshrc. (+)
3940 /etc/csh.login Read by login shells after /etc/csh.cshrc. ConvexOS,
3941 Stellix and Intel use /etc/login, NeXTs use
3942 /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
3943 AMIX, Cray and IRIX use /etc/cshrc.
3944 ~/.tcshrc (+) Read by every shell after /etc/csh.cshrc or its equiva‐
3945 lent.
3946 ~/.cshrc Read by every shell, if ~/.tcshrc doesn't exist, after
3947 /etc/csh.cshrc or its equivalent. This manual uses
3948 `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
3949 found, ~/.cshrc'.
3950 ~/.history Read by login shells after ~/.tcshrc if savehist is
3951 set, but see also histfile.
3952 ~/.login Read by login shells after ~/.tcshrc or ~/.history.
3953 The shell may be compiled to read ~/.login before
3954 instead of after ~/.tcshrc and ~/.history; see the ver‐
3955 sion shell variable.
3956 ~/.cshdirs (+) Read by login shells after ~/.login if savedirs is set,
3957 but see also dirsfile.
3958 /etc/csh.logout Read by login shells at logout. ConvexOS, Stellix and
3959 Intel use /etc/logout and NeXTs use /etc/logout.std.
3960 A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
3961 but read this file in tcsh anyway. Solaris 2.x does
3962 not have it either, but tcsh reads /etc/.logout. (+)
3963 ~/.logout Read by login shells at logout after /etc/csh.logout or
3964 its equivalent.
3965 /bin/sh Used to interpret shell scripts not starting with a
3966 `#'.
3967 /tmp/sh* Temporary file for `<<'.
3968 /etc/passwd Source of home directories for `~name' substitutions.
3969 The order in which startup files are read may differ if the shell was
3971 so compiled; see Startup and shutdown and the version shell variable.
3972
3974 This manual describes tcsh as a single entity, but experienced csh(1)
3975 users will want to pay special attention to tcsh's new features.
3976 A command-line editor, which supports GNU Emacs or vi(1)-style key
3978 bindings. See The command-line editor and Editor commands.
3979 Programmable, interactive word completion and listing. See Completion
3981 and listing and the complete and uncomplete builtin commands.
3982 Spelling correction (q.v.) of filenames, commands and variables.
3984 Editor commands (q.v.) which perform other useful functions in the mid‐
3986 dle of typed commands, including documentation lookup (run-help), quick
3987 editor restarting (run-fg-editor) and command resolution (which-com‐
3988 mand).
3989 An enhanced history mechanism. Events in the history list are time-
3991 stamped. See also the history command and its associated shell vari‐
3992 ables, the previously undocumented `#' event specifier and new modi‐
3993 fiers under History substitution, the *-history, history-search-*, i-
3994 search-*, vi-search-* and toggle-literal-history editor commands and
3995 the histlit shell variable.
3996 Enhanced directory parsing and directory stack handling. See the cd,
3998 pushd, popd and dirs commands and their associated shell variables, the
3999 description of Directory stack substitution, the dirstack, owd and sym‐
4000 links shell variables and the normalize-command and normalize-path edi‐
4001 tor commands.
4002 Negation in glob-patterns. See Filename substitution.
4004 New File inquiry operators (q.v.) and a filetest builtin which uses
4006 them.
4007 A variety of Automatic, periodic and timed events (q.v.) including
4009 scheduled events, special aliases, automatic logout and terminal lock‐
4010 ing, command timing and watching for logins and logouts.
4011 Support for the Native Language System (see Native Language System sup‐
4013 port), OS variant features (see OS variant support and the echo_style
4014 shell variable) and system-dependent file locations (see FILES).
4015 Extensive terminal-management capabilities. See Terminal management.
4017 New builtin commands including builtins, hup, ls-F, newgrp, printenv,
4019 which and where (q.v.).
4020 New variables that make useful information easily available to the
4022 shell. See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version
4023 shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
4024 environment variables.
4025 A new syntax for including useful information in the prompt string (see
4027 prompt). and special prompts for loops and spelling correction (see
4028 prompt2 and prompt3).
4029 Read-only variables. See Variable substitution.
4031
4033 When a suspended command is restarted, the shell prints the directory
4034 it started in if this is different from the current directory. This
4035 can be misleading (i.e., wrong) as the job may have changed directories
4036 internally.
4037 Shell builtin functions are not stoppable/restartable. Command
4039 sequences of the form `a ; b ; c' are also not handled gracefully when
4040 stopping is attempted. If you suspend `b', the shell will then immedi‐
4041 ately execute `c'. This is especially noticeable if this expansion
4042 results from an alias. It suffices to place the sequence of commands
4043 in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.
4044 Control over tty output after processes are started is primitive; per‐
4046 haps this will inspire someone to work on a good virtual terminal
4047 interface. In a virtual terminal interface much more interesting
4048 things could be done with output control.
4049 Alias substitution is most often used to clumsily simulate shell proce‐
4051 dures; shell procedures should be provided rather than aliases.
4052 Commands within loops are not placed in the history list. Control
4054 structures should be parsed rather than being recognized as built-in
4055 commands. This would allow control commands to be placed anywhere, to
4056 be combined with `|', and to be used with `&' and `;' metasyntax.
4057 foreach doesn't ignore here documents when looking for its end.
4059 It should be possible to use the `:' modifiers on the output of command
4061 substitutions.
4062 The screen update for lines longer than the screen width is very poor
4064 if the terminal cannot move the cursor up (i.e., terminal type `dumb').
4065 HPATH and NOREBIND don't need to be environment variables.
4067 Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
4069 `~' are not negated correctly.
4070 The single-command form of if does output redirection even if the
4072 expression is false and the command is not executed.
4073 ls-F includes file identification characters when sorting filenames and
4075 does not handle control characters in filenames well. It cannot be
4076 interrupted.
4077 Command substitution supports multiple commands and conditions, but not
4079 cycles or backward gotos.
4080 Report bugs at http://bugs.gw.com/, preferably with fixes. If you want
4082 to help maintain and test tcsh, send mail to tcsh-request@mx.gw.com
4083 with the text `subscribe tcsh' on a line by itself in the body.
4084
4086 In 1964, DEC produced the PDP-6. The PDP-10 was a later re-implementa‐
4087 tion. It was re-christened the DECsystem-10 in 1970 or so when DEC
4088 brought out the second model, the KI10.
4089 TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
4091 think tank) in 1972 as an experiment in demand-paged virtual memory
4092 operating systems. They built a new pager for the DEC PDP-10 and cre‐
4093 ated the OS to go with it. It was extremely successful in academia.
4094 In 1975, DEC brought out a new model of the PDP-10, the KL10; they
4096 intended to have only a version of TENEX, which they had licensed from
4097 BBN, for the new box. They called their version TOPS-20 (their capi‐
4098 talization is trademarked). A lot of TOPS-10 users (`The OPerating
4099 System for PDP-10') objected; thus DEC found themselves supporting two
4100 incompatible systems on the same hardware--but then there were 6 on the
4101 PDP-11!
4102 TENEX, and TOPS-20 to version 3, had command completion via a user-
4104 code-level subroutine library called ULTCMD. With version 3, DEC moved
4105 all that capability and more into the monitor (`kernel' for you Unix
4106 types), accessed by the COMND% JSYS (`Jump to SYStem' instruction, the
4107 supervisor call mechanism [are my IBM roots also showing?]).
4108 The creator of tcsh was impressed by this feature and several others of
4110 TENEX and TOPS-20, and created a version of csh which mimicked them.
4111
4113 The system limits argument lists to ARG_MAX characters.
4114 The number of arguments to a command which involves filename expansion
4116 is limited to 1/6th the number of characters allowed in an argument
4117 list.
4118 Command substitutions may substitute no more characters than are
4120 allowed in an argument list.
4121 To detect looping, the shell restricts the number of alias substitu‐
4123 tions on a single line to 20.
4124
4126 csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
4127 tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
4128 pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
4129 malloc(3), setlocale(3), tty(4), a.out(5), termcap(5), environ(7),
4130 termio(7), Introduction to the C Shell
4131
4133 This manual documents tcsh 6.17.00 (Astron) 2009-07-10.
4134
4136 William Joy
4137 Original author of csh(1)
4138 J.E. Kulp, IIASA, Laxenburg, Austria
4139 Job control and directory stack features
4140 Ken Greer, HP Labs, 1981
4141 File name completion
4142 Mike Ellis, Fairchild, 1983
4143 Command name recognition/completion
4144 Paul Placeway, Ohio State CIS Dept., 1983-1993
4145 Command line editor, prompt routines, new glob syntax and numerous
4146 fixes and speedups
4147 Karl Kleinpaste, CCI 1983-4
4148 Special aliases, directory stack extraction stuff, login/logout
4149 watch, scheduled events, and the idea of the new prompt format
4150 Rayan Zachariassen, University of Toronto, 1984
4151 ls-F and which builtins and numerous bug fixes, modifications and
4152 speedups
4153 Chris Kingsley, Caltech
4154 Fast storage allocator routines
4155 Chris Grevstad, TRW, 1987
4156 Incorporated 4.3BSD csh into tcsh
4157 Christos S. Zoulas, Cornell U. EE Dept., 1987-94
4158 Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
4159 SHORT_STRINGS support and a new version of sh.glob.c
4160 James J Dempsey, BBN, and Paul Placeway, OSU, 1988
4161 A/UX port
4162 Daniel Long, NNSC, 1988
4163 wordchars
4164 Patrick Wolfe, Kuck and Associates, Inc., 1988
4165 vi mode cleanup
4166 David C Lawrence, Rensselaer Polytechnic Institute, 1989
4167 autolist and ambiguous completion listing
4168 Alec Wolman, DEC, 1989
4169 Newlines in the prompt
4170 Matt Landau, BBN, 1989
4171 ~/.tcshrc
4172 Ray Moody, Purdue Physics, 1989
4173 Magic space bar history expansion
4174 Mordechai ????, Intel, 1989
4175 printprompt() fixes and additions
4176 Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
4177 Automatic spelling correction and prompt3
4178 Per Hedeland, Ellemtel, Sweden, 1990-
4179 Various bugfixes, improvements and manual updates
4180 Hans J. Albertsson (Sun Sweden)
4181 ampm, settc and telltc
4182 Michael Bloom
4183 Interrupt handling fixes
4184 Michael Fine, Digital Equipment Corp
4185 Extended key support
4186 Eric Schnoebelen, Convex, 1990
4187 Convex support, lots of csh bug fixes, save and restore of directory
4188 stack
4189 Ron Flax, Apple, 1990
4190 A/UX 2.0 (re)port
4191 Dan Oscarsson, LTH Sweden, 1990
4192 NLS support and simulated NLS support for non NLS sites, fixes
4193 Johan Widen, SICS Sweden, 1990
4194 shlvl, Mach support, correct-line, 8-bit printing
4195 Matt Day, Sanyo Icon, 1990
4196 POSIX termio support, SysV limit fixes
4197 Jaap Vermeulen, Sequent, 1990-91
4198 Vi mode fixes, expand-line, window change fixes, Symmetry port
4199 Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
4200 autolist beeping options, modified the history search to search for
4201 the whole string from the beginning of the line to the cursor.
4202 Scott Krotz, Motorola, 1991
4203 Minix port
4204 David Dawes, Sydney U. Australia, Physics Dept., 1991
4205 SVR4 job control fixes
4206 Jose Sousa, Interactive Systems Corp., 1991
4207 Extended vi fixes and vi delete command
4208 Marc Horowitz, MIT, 1991
4209 ANSIfication fixes, new exec hashing code, imake fixes, where
4210 Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
4211 ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
4212 and various other portability changes and bug fixes
4213 Jeff Fink, 1992
4214 complete-word-fwd and complete-word-back
4215 Harry C. Pulley, 1992
4216 Coherent port
4217 Andy Phillips, Mullard Space Science Lab U.K., 1992
4218 VMS-POSIX port
4219 Beto Appleton, IBM Corp., 1992
4220 Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
4221 SIGHUP
4222 Scott Bolte, Cray Computer Corp., 1992
4223 CSOS port
4224 Kaveh R. Ghazi, Rutgers University, 1992
4225 Tek, m88k, Titan and Masscomp ports and fixes. Added autoconf sup‐
4226 port.
4227 Mark Linderman, Cornell University, 1992
4228 OS/2 port
4229 Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
4230 Linux port
4231 Tim P. Starrin, NASA Langley Research Center Operations, 1993
4232 Read-only variables
4233 Dave Schweisguth, Yale University, 1993-4
4234 New man page and tcsh.man2html
4235 Larry Schwimmer, Stanford University, 1993
4236 AFS and HESIOD patches
4237 Luke Mewburn, RMIT University, 1994-6
4238 Enhanced directory printing in prompt, added ellipsis and rprompt.
4239 Edward Hutchins, Silicon Graphics Inc., 1996
4240 Added implicit cd.
4241 Martin Kraemer, 1997
4242 Ported to Siemens Nixdorf EBCDIC machine
4243 Amol Deshpande, Microsoft, 1997
4244 Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
4245 library and message catalog code to interface to Windows.
4246 Taga Nayuta, 1998
4247 Color ls additions.
4248
4250 Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
4251 Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
4252 the other people at Ohio State for suggestions and encouragement
4253 All the people on the net, for putting up with, reporting bugs in, and
4255 suggesting new additions to each and every version
4256 Richard M. Alderson III, for writing the `T in tcsh' section
4258Astron 6.17.00 10 July 2009 TCSH(1)