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 ignores ~/.tcshrc, and thus starts faster.
55 -F The shell uses fork(2) instead of vfork(2) to spawn processes.
57 (Convex/OS only) (+)
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 `!\3d'.
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 inside l and r. The
851 character `&' in the r is replaced by l; `\' also quotes
852 `&'. If l is empty (``''), the l from a previous substitu‐
853 tion or the s from a previous `?s?' event specification is
854 used. The trailing delimiter may be omitted if it is imme‐
855 diately followed by a newline.
856 & Repeat the previous substitution.
857 g Apply the following modifier once to each word.
858 a (+) Apply the following modifier as many times as possible to a
859 single word. `a' and `g' can be used together to apply a
860 modifier globally. In the current implementation, using
861 the `a' and `s' modifiers together can lead to an infinite
862 loop. For example, `:as/f/ff/' will never terminate. This
863 behavior might change in the future.
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 up to 20 letters and digits starting with a
1003 letter. The underscore character is considered a letter. If
1004 name is not a shell variable, but is set in the environment,
1005 then that value is returned (but `:' modifiers and the other
1006 forms given below are 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 it is given neither a -c nor a -t option, the shell hashes
1232 the names in these directories into an internal table so that it will
1233 try an execve(2) in only a directory where there is a possibility that
1234 the command resides there. This greatly speeds command location when a
1235 large number of directories are present in the search path. If this
1236 mechanism has been turned off (via unhash), if the shell was given a -c
1237 or -t argument or in any case for each directory component of path
1238 which does not begin with a `/', the shell concatenates the current
1239 working directory with the given command name to form a path name of a
1240 file which it then attempts to execute.
1241 If the file has execute permissions but is not an executable to the
1243 system (i.e., it is neither an executable binary nor a script that
1244 specifies its interpreter), then it is assumed to be a file containing
1245 shell commands and a new shell is spawned to read it. The shell spe‐
1246 cial alias may be set to specify an interpreter other than the shell
1247 itself.
1248 On systems which do not understand the `#!' script interpreter conven‐
1250 tion the shell may be compiled to emulate it; see the version shell
1251 variable. If so, the shell checks the first line of the file to see if
1252 it is of the form `#!interpreter arg ...'. If it is, the shell starts
1253 interpreter with the given args and feeds the file to it on standard
1254 input.
1255 Input/output
1257 The standard input and standard output of a command may be redirected
1258 with the following syntax:
1259 < name Open file name (which is first variable, command and filename
1261 expanded) as the standard input.
1262 << word Read the shell input up to a line which is identical to word.
1263 word is not subjected to variable, filename or command substi‐
1264 tution, and each input line is compared to word before any sub‐
1265 stitutions are done on this input line. Unless a quoting `\',
1266 `"', `' or ``' appears in word variable and command substitu‐
1267 tion is performed on the intervening lines, allowing `\' to
1268 quote `$', `\' and ``'. Commands which are substituted have
1269 all blanks, tabs, and newlines preserved, except for the final
1270 newline which is dropped. The resultant text is placed in an
1271 anonymous temporary file which is given to the command as stan‐
1272 dard input.
1273 > name
1274 >! name
1275 >& name
1276 >&! name
1277 The file name is used as standard output. If the file does not
1278 exist then it is created; if the file exists, it is truncated,
1279 its previous contents being lost.
1280 If the shell variable noclobber is set, then the file must not
1282 exist or be a character special file (e.g., a terminal or
1283 `/dev/null') or an error results. This helps prevent acciden‐
1284 tal destruction of files. In this case the `!' forms can be
1285 used to suppress this check.
1286 The forms involving `&' route the diagnostic output into the
1288 specified file as well as the standard output. name is
1289 expanded in the same way as `<' input filenames are.
1290 >> name
1291 >>& name
1292 >>! name
1293 >>&! name
1294 Like `>', but appends output to the end of name. If the shell
1295 variable noclobber is set, then it is an error for the file not
1296 to exist, unless one of the `!' forms is given.
1297 A command receives the environment in which the shell was invoked as
1299 modified by the input-output parameters and the presence of the command
1300 in a pipeline. Thus, unlike some previous shells, commands run from a
1301 file of shell commands have no access to the text of the commands by
1302 default; rather they receive the original standard input of the shell.
1303 The `<<' mechanism should be used to present inline data. This permits
1304 shell command scripts to function as components of pipelines and allows
1305 the shell to block read its input. Note that the default standard
1306 input for a command run detached is not the empty file /dev/null, but
1307 the original standard input of the shell. If this is a terminal and if
1308 the process attempts to read from the terminal, then the process will
1309 block and the user will be notified (see Jobs).
1310 Diagnostic output may be directed through a pipe with the standard out‐
1312 put. Simply use the form `|&' rather than just `|'.
1313 The shell cannot presently redirect diagnostic output without also
1315 redirecting standard output, but `(command > output-file) >& error-
1316 file' is often an acceptable workaround. Either output-file or error-
1317 file may be `/dev/tty' to send output to the terminal.
1318 Features
1320 Having described how the shell accepts, parses and executes command
1321 lines, we now turn to a variety of its useful features.
1322 Control flow
1324 The shell contains a number of commands which can be used to regulate
1325 the flow of control in command files (shell scripts) and (in limited
1326 but useful ways) from terminal input. These commands all operate by
1327 forcing the shell to reread or skip in its input and, due to the imple‐
1328 mentation, restrict the placement of some of the commands.
1329 The foreach, switch, and while statements, as well as the if-then-else
1331 form of the if statement, require that the major keywords appear in a
1332 single simple command on an input line as shown below.
1333 If the shell's input is not seekable, the shell buffers up input when‐
1335 ever a loop is being read and performs seeks in this internal buffer to
1336 accomplish the rereading implied by the loop. (To the extent that this
1337 allows, backward gotos will succeed on non-seekable inputs.)
1338 Expressions
1340 The if, while and exit builtin commands use expressions with a common
1341 syntax. The expressions can include any of the operators described in
1342 the next three sections. Note that the @ builtin command (q.v.) has
1343 its own separate syntax.
1344 Logical, arithmetical and comparison operators
1346 These operators are similar to those of C and have the same precedence.
1347 They include
1348 || && | ^ & == != =~ !~ <= >=
1350 < > << >> + - * / % ! ~ ( )
1351 Here the precedence increases to the right, `==' `!=' `=~' and `!~',
1353 `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%'
1354 being, in groups, at the same level. The `==' `!=' `=~' and `!~' oper‐
1355 ators compare their arguments as strings; all others operate on num‐
1356 bers. The operators `=~' and `!~' are like `!=' and `==' except that
1357 the right hand side is a glob-pattern (see Filename substitution)
1358 against which the left hand operand is matched. This reduces the need
1359 for use of the switch builtin command in shell scripts when all that is
1360 really needed is pattern matching.
1361 Strings which begin with `0' are considered octal numbers. Null or
1363 missing arguments are considered `0'. The results of all expressions
1364 are strings, which represent decimal numbers. It is important to note
1365 that no two components of an expression can appear in the same word;
1366 except when adjacent to components of expressions which are syntacti‐
1367 cally significant to the parser (`&' `|' `<' `>' `(' `)') they should
1368 be surrounded by spaces.
1369 Command exit status
1371 Commands can be executed in expressions and their exit status returned
1372 by enclosing them in braces (`{}'). Remember that the braces should be
1373 separated from the words of the command by spaces. Command executions
1374 succeed, returning true, i.e., `1', if the command exits with status 0,
1375 otherwise they fail, returning false, i.e., `0'. If more detailed sta‐
1376 tus information is required then the command should be executed outside
1377 of an expression and the status shell variable examined.
1378 File inquiry operators
1380 Some of these operators perform true/false tests on files and related
1381 objects. They are of the form -op file, where op is one of
1382 r Read access
1384 w Write access
1385 x Execute access
1386 X Executable in the path or shell builtin, e.g., `-X ls' and `-X
1387 ls-F' are generally true, but `-X /bin/ls' is not (+)
1388 e Existence
1389 o Ownership
1390 z Zero size
1391 s Non-zero size (+)
1392 f Plain file
1393 d Directory
1394 l Symbolic link (+) *
1395 b Block special file (+)
1396 c Character special file (+)
1397 p Named pipe (fifo) (+) *
1398 S Socket special file (+) *
1399 u Set-user-ID bit is set (+)
1400 g Set-group-ID bit is set (+)
1401 k Sticky bit is set (+)
1402 t file (which must be a digit) is an open file descriptor for a
1403 terminal device (+)
1404 R Has been migrated (convex only) (+)
1405 L Applies subsequent operators in a multiple-operator test to a
1406 symbolic link rather than to the file to which the link points
1407 (+) *
1408 file is command and filename expanded and then tested to see if it has
1410 the specified relationship to the real user. If file does not exist or
1411 is inaccessible or, for the operators indicated by `*', if the speci‐
1412 fied file type does not exist on the current system, then all enquiries
1413 return false, i.e., `0'.
1414 These operators may be combined for conciseness: `-xy file' is equiva‐
1416 lent to `-x file && -y file'. (+) For example, `-fx' is true (returns
1417 `1') for plain executable files, but not for directories.
1418 L may be used in a multiple-operator test to apply subsequent operators
1420 to a symbolic link rather than to the file to which the link points.
1421 For example, `-lLo' is true for links owned by the invoking user. Lr,
1422 Lw and Lx are always true for links and false for non-links. L has a
1423 different meaning when it is the last operator in a multiple-operator
1424 test; see below.
1425 It is possible but not useful, and sometimes misleading, to combine
1427 operators which expect file to be a file with operators which do not,
1428 (e.g., X and t). Following L with a non-file operator can lead to par‐
1429 ticularly strange results.
1430 Other operators return other information, i.e., not just `0' or `1'.
1432 (+) They have the same format as before; op may be one of
1433 A Last file access time, as the number of seconds since the
1435 epoch
1436 A: Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
1437 1993'
1438 M Last file modification time
1439 M: Like M, but in timestamp format
1440 C Last inode modification time
1441 C: Like C, but in timestamp format
1442 D Device number
1443 I Inode number
1444 F Composite file identifier, in the form device:inode
1445 L The name of the file pointed to by a symbolic link
1446 N Number of (hard) links
1447 P Permissions, in octal, without leading zero
1448 P: Like P, with leading zero
1449 Pmode Equivalent to `-P file & mode', e.g., `-P22 file' returns
1450 `22' if file is writable by group and other, `20' if by
1451 group only, and `0' if by neither
1452 Pmode: Like Pmode:, with leading zero
1453 U Numeric userid
1454 U: Username, or the numeric userid if the username is unknown
1455 G Numeric groupid
1456 G: Groupname, or the numeric groupid if the groupname is
1457 unknown
1458 Z Size, in bytes
1459 Only one of these operators may appear in a multiple-operator test, and
1461 it must be the last. Note that L has a different meaning at the end of
1462 and elsewhere in a multiple-operator test. Because `0' is a valid
1463 return value for many of these operators, they do not return `0' when
1464 they fail: most return `-1', and F returns `:'.
1465 If the shell is compiled with POSIX defined (see the version shell
1467 variable), the result of a file inquiry is based on the permission bits
1468 of the file and not on the result of the access(2) system call. For
1469 example, if one tests a file with -w whose permissions would ordinarily
1470 allow writing but which is on a file system mounted read-only, the test
1471 will succeed in a POSIX shell but fail in a non-POSIX shell.
1472 File inquiry operators can also be evaluated with the filetest builtin
1474 command (q.v.) (+).
1475 Jobs
1477 The shell associates a job with each pipeline. It keeps a table of
1478 current jobs, printed by the jobs command, and assigns them small inte‐
1479 ger numbers. When a job is started asynchronously with `&', the shell
1480 prints a line which looks like
1481 [1] 1234
1483 indicating that the job which was started asynchronously was job number
1485 1 and had one (top-level) process, whose process id was 1234.
1486 If you are running a job and wish to do something else you may hit the
1488 suspend key (usually `^Z'), which sends a STOP signal to the current
1489 job. The shell will then normally indicate that the job has been `Sus‐
1490 pended' and print another prompt. If the listjobs shell variable is
1491 set, all jobs will be listed like the jobs builtin command; if it is
1492 set to `long' the listing will be in long format, like `jobs -l'. You
1493 can then manipulate the state of the suspended job. You can put it in
1494 the ``background'' with the bg command or run some other commands and
1495 eventually bring the job back into the ``foreground'' with fg. (See
1496 also the run-fg-editor editor command.) A `^Z' takes effect immedi‐
1497 ately and is like an interrupt in that pending output and unread input
1498 are discarded when it is typed. The wait builtin command causes the
1499 shell to wait for all background jobs to complete.
1500 The `^]' key sends a delayed suspend signal, which does not generate a
1502 STOP signal until a program attempts to read(2) it, to the current job.
1503 This can usefully be typed ahead when you have prepared some commands
1504 for a job which you wish to stop after it has read them. The `^Y' key
1505 performs this function in csh(1); in tcsh, `^Y' is an editing command.
1506 (+)
1507 A job being run in the background stops if it tries to read from the
1509 terminal. Background jobs are normally allowed to produce output, but
1510 this can be disabled by giving the command `stty tostop'. If you set
1511 this tty option, then background jobs will stop when they try to pro‐
1512 duce output like they do when they try to read input.
1513 There are several ways to refer to jobs in the shell. The character
1515 `%' introduces a job name. If you wish to refer to job number 1, you
1516 can name it as `%1'. Just naming a job brings it to the foreground;
1517 thus `%1' is a synonym for `fg %1', bringing job 1 back into the fore‐
1518 ground. Similarly, saying `%1 &' resumes job 1 in the background, just
1519 like `bg %1'. A job can also be named by an unambiguous prefix of the
1520 string typed in to start it: `%ex' would normally restart a suspended
1521 ex(1) job, if there were only one suspended job whose name began with
1522 the string `ex'. It is also possible to say `%?string' to specify a
1523 job whose text contains string, if there is only one such job.
1524 The shell maintains a notion of the current and previous jobs. In out‐
1526 put pertaining to jobs, the current job is marked with a `+' and the
1527 previous job with a `-'. The abbreviations `%+', `%', and (by analogy
1528 with the syntax of the history mechanism) `%%' all refer to the current
1529 job, and `%-' refers to the previous job.
1530 The job control mechanism requires that the stty(1) option `new' be set
1532 on some systems. It is an artifact from a `new' implementation of the
1533 tty driver which allows generation of interrupt characters from the
1534 keyboard to tell jobs to stop. See stty(1) and the setty builtin com‐
1535 mand for details on setting options in the new tty driver.
1536 Status reporting
1538 The shell learns immediately whenever a process changes state. It nor‐
1539 mally informs you whenever a job becomes blocked so that no further
1540 progress is possible, but only right before it prints a prompt. This
1541 is done so that it does not otherwise disturb your work. If, however,
1542 you set the shell variable notify, the shell will notify you immedi‐
1543 ately of changes of status in background jobs. There is also a shell
1544 command notify which marks a single process so that its status changes
1545 will be immediately reported. By default notify marks the current
1546 process; simply say `notify' after starting a background job to mark
1547 it.
1548 When you try to leave the shell while jobs are stopped, you will be
1550 warned that `You have stopped jobs.' You may use the jobs command to
1551 see what they are. If you do this or immediately try to exit again,
1552 the shell will not warn you a second time, and the suspended jobs will
1553 be terminated.
1554 Automatic, periodic and timed events (+)
1556 There are various ways to run commands and take other actions automati‐
1557 cally at various times in the ``life cycle'' of the shell. They are
1558 summarized here, and described in detail under the appropriate Builtin
1559 commands, Special shell variables and Special aliases.
1560 The sched builtin command puts commands in a scheduled-event list, to
1562 be executed by the shell at a given time.
1563 The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
1565 aliases can be set, respectively, to execute commands when the shell
1566 wants to ring the bell, when the working directory changes, every tpe‐
1567 riod minutes, before each prompt, before each command gets executed,
1568 after each command gets executed, and when a job is started or is
1569 brought into the foreground.
1570 The autologout shell variable can be set to log out or lock the shell
1572 after a given number of minutes of inactivity.
1573 The mail shell variable can be set to check for new mail periodically.
1575 The printexitvalue shell variable can be set to print the exit status
1577 of commands which exit with a status other than zero.
1578 The rmstar shell variable can be set to ask the user, when `rm *' is
1580 typed, if that is really what was meant.
1581 The time shell variable can be set to execute the time builtin command
1583 after the completion of any process that takes more than a given number
1584 of CPU seconds.
1585 The watch and who shell variables can be set to report when selected
1587 users log in or out, and the log builtin command reports on those users
1588 at any time.
1589 Native Language System support (+)
1591 The shell is eight bit clean (if so compiled; see the version shell
1592 variable) and thus supports character sets needing this capability.
1593 NLS support differs depending on whether or not the shell was compiled
1594 to use the system's NLS (again, see version). In either case, 7-bit
1595 ASCII is the default character code (e.g., the classification of which
1596 characters are printable) and sorting, and changing the LANG or
1597 LC_CTYPE environment variables causes a check for possible changes in
1598 these respects.
1599 When using the system's NLS, the setlocale(3) function is called to
1601 determine appropriate character code/classification and sorting (e.g.,
1602 a 'en_CA.UTF-8' would yield "UTF-8" as a character code). This func‐
1603 tion typically examines the LANG and LC_CTYPE environment variables;
1604 refer to the system documentation for further details. When not using
1605 the system's NLS, the shell simulates it by assuming that the ISO
1606 8859-1 character set is used whenever either of the LANG and LC_CTYPE
1607 variables are set, regardless of their values. Sorting is not affected
1608 for the simulated NLS.
1609 In addition, with both real and simulated NLS, all printable characters
1611 in the range \200-\377, i.e., those that have M-char bindings, are
1612 automatically rebound to self-insert-command. The corresponding bind‐
1613 ing for the escape-char sequence, if any, is left alone. These charac‐
1614 ters are not rebound if the NOREBIND environment variable is set. This
1615 may be useful for the simulated NLS or a primitive real NLS which
1616 assumes full ISO 8859-1. Otherwise, all M-char bindings in the range
1617 \240-\377 are effectively undone. Explicitly rebinding the relevant
1618 keys with bindkey is of course still possible.
1619 Unknown characters (i.e., those that are neither printable nor control
1621 characters) are printed in the format \nnn. If the tty is not in 8 bit
1622 mode, other 8 bit characters are printed by converting them to ASCII
1623 and using standout mode. The shell never changes the 7/8 bit mode of
1624 the tty and tracks user-initiated changes of 7/8 bit mode. NLS users
1625 (or, for that matter, those who want to use a meta key) may need to
1626 explicitly set the tty in 8 bit mode through the appropriate stty(1)
1627 command in, e.g., the ~/.login file.
1628 OS variant support (+)
1630 A number of new builtin commands are provided to support features in
1631 particular operating systems. All are described in detail in the
1632 Builtin commands section.
1633 On systems that support TCF (aix-ibm370, aix-ps2), getspath and
1635 setspath get and set the system execution path, getxvers and setxvers
1636 get and set the experimental version prefix and migrate migrates pro‐
1637 cesses between sites. The jobs builtin prints the site on which each
1638 job is executing.
1639 Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
1641 operating system.
1642 Under Domain/OS, inlib adds shared libraries to the current environ‐
1644 ment, rootnode changes the rootnode and ver changes the systype.
1645 Under Mach, setpath is equivalent to Mach's setpath(1).
1647 Under Masscomp/RTU and Harris CX/UX, universe sets the universe.
1649 Under Harris CX/UX, ucb or att runs a command under the specified uni‐
1651 verse.
1652 Under Convex/OS, warp prints or sets the universe.
1654 The VENDOR, OSTYPE and MACHTYPE environment variables indicate respec‐
1656 tively the vendor, operating system and machine type (microprocessor
1657 class or machine model) of the system on which the shell thinks it is
1658 running. These are particularly useful when sharing one's home direc‐
1659 tory between several types of machines; one can, for example,
1660 set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)
1662 in one's ~/.login and put executables compiled for each machine in the
1664 appropriate directory.
1665 The version shell variable indicates what options were chosen when the
1667 shell was compiled.
1668 Note also the newgrp builtin, the afsuser and echo_style shell vari‐
1670 ables and the system-dependent locations of the shell's input files
1671 (see FILES).
1672 Signal handling
1674 Login shells ignore interrupts when reading the file ~/.logout. The
1675 shell ignores quit signals unless started with -q. Login shells catch
1676 the terminate signal, but non-login shells inherit the terminate behav‐
1677 ior from their parents. Other signals have the values which the shell
1678 inherited from its parent.
1679 In shell scripts, the shell's handling of interrupt and terminate sig‐
1681 nals can be controlled with onintr, and its handling of hangups can be
1682 controlled with hup and nohup.
1683 The shell exits on a hangup (see also the logout shell variable). By
1685 default, the shell's children do too, but the shell does not send them
1686 a hangup when it exits. hup arranges for the shell to send a hangup to
1687 a child when it exits, and nohup sets a child to ignore hangups.
1688 Terminal management (+)
1690 The shell uses three different sets of terminal (``tty'') modes:
1691 `edit', used when editing, `quote', used when quoting literal charac‐
1692 ters, and `execute', used when executing commands. The shell holds
1693 some settings in each mode constant, so commands which leave the tty in
1694 a confused state do not interfere with the shell. The shell also
1695 matches changes in the speed and padding of the tty. The list of tty
1696 modes that are kept constant can be examined and modified with the
1697 setty builtin. Note that although the editor uses CBREAK mode (or its
1698 equivalent), it takes typed-ahead characters anyway.
1699 The echotc, settc and telltc commands can be used to manipulate and
1701 debug terminal capabilities from the command line.
1702 On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win‐
1704 dow resizing automatically and adjusts the environment variables LINES
1705 and COLUMNS if set. If the environment variable TERMCAP contains li#
1706 and co# fields, the shell adjusts them to reflect the new window size.
1707
1709 The next sections of this manual describe all of the available Builtin
1710 commands, Special aliases and Special shell variables.
1711 Builtin commands
1713 %job A synonym for the fg builtin command.
1714 %job & A synonym for the bg builtin command.
1716 : Does nothing, successfully.
1718 @
1720 @ name = expr
1721 @ name[index] = expr
1722 @ name++|--
1723 @ name[index]++|--
1724 The first form prints the values of all shell variables.
1725 The second form assigns the value of expr to name. The third
1727 form assigns the value of expr to the index'th component of
1728 name; both name and its index'th component must already exist.
1729 expr may contain the operators `*', `+', etc., as in C. If
1731 expr contains `<', `>', `&' or `' then at least that part of
1732 expr must be placed within `()'. Note that the syntax of expr
1733 has nothing to do with that described under Expressions.
1734 The fourth and fifth forms increment (`++') or decrement (`--')
1736 name or its index'th component.
1737 The space between `@' and name is required. The spaces between
1739 name and `=' and between `=' and expr are optional. Components
1740 of expr must be separated by spaces.
1741 alias [name [wordlist]]
1743 Without arguments, prints all aliases. With name, prints the
1744 alias for name. With name and wordlist, assigns wordlist as
1745 the alias of name. wordlist is command and filename substi‐
1746 tuted. name may not be `alias' or `unalias'. See also the
1747 unalias builtin command.
1748 alloc Shows the amount of dynamic memory acquired, broken down into
1750 used and free memory. With an argument shows the number of
1751 free and used blocks in each size category. The categories
1752 start at size 8 and double at each step. This command's output
1753 may vary across system types, because systems other than the
1754 VAX may use a different memory allocator.
1755 bg [%job ...]
1757 Puts the specified jobs (or, without arguments, the current
1758 job) into the background, continuing each if it is stopped.
1759 job may be a number, a string, `', `%', `+' or `-' as described
1760 under Jobs.
1761 bindkey [-l|-d|-e|-v|-u] (+)
1763 bindkey [-a] [-b] [-k] [-r] [--] key (+)
1764 bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
1765 Without options, the first form lists all bound keys and the
1766 editor command to which each is bound, the second form lists
1767 the editor command to which key is bound and the third form
1768 binds the editor command command to key. Options include:
1769 -l Lists all editor commands and a short description of each.
1771 -d Binds all keys to the standard bindings for the default
1772 editor.
1773 -e Binds all keys to the standard GNU Emacs-like bindings.
1774 -v Binds all keys to the standard vi(1)-like bindings.
1775 -a Lists or changes key-bindings in the alternative key map.
1776 This is the key map used in vi command mode.
1777 -b key is interpreted as a control character written ^charac‐
1778 ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char‐
1779 acter written M-character (e.g., `M-A'), a function key
1780 written F-string (e.g., `F-string'), or an extended prefix
1781 key written X-character (e.g., `X-A').
1782 -k key is interpreted as a symbolic arrow key name, which may
1783 be one of `down', `up', `left' or `right'.
1784 -r Removes key's binding. Be careful: `bindkey -r' does not
1785 bind key to self-insert-command (q.v.), it unbinds key com‐
1786 pletely.
1787 -c command is interpreted as a builtin or external command
1788 instead of an editor command.
1789 -s command is taken as a literal string and treated as termi‐
1790 nal input when key is typed. Bound keys in command are
1791 themselves reinterpreted, and this continues for ten levels
1792 of interpretation.
1793 -- Forces a break from option processing, so the next word is
1794 taken as key even if it begins with '-'.
1795 -u (or any invalid option)
1796 Prints a usage message.
1797 key may be a single character or a string. If a command is
1799 bound to a string, the first character of the string is bound
1800 to sequence-lead-in and the entire string is bound to the com‐
1801 mand.
1802 Control characters in key can be literal (they can be typed by
1804 preceding them with the editor command quoted-insert, normally
1805 bound to `^V') or written caret-character style, e.g., `^A'.
1806 Delete is written `^?' (caret-question mark). key and command
1807 can contain backslashed escape sequences (in the style of Sys‐
1808 tem V echo(1)) as follows:
1809 \a Bell
1811 \b Backspace
1812 \e Escape
1813 \f Form feed
1814 \n Newline
1815 \r Carriage return
1816 \t Horizontal tab
1817 \v Vertical tab
1818 \nnn The ASCII character corresponding to the octal num‐
1819 ber nnn
1820 `\' nullifies the special meaning of the following character,
1822 if it has any, notably `\' and `^'.
1823 bs2cmd bs2000-command (+)
1825 Passes bs2000-command to the BS2000 command interpreter for
1826 execution. Only non-interactive commands can be executed, and
1827 it is not possible to execute any command that would overlay
1828 the image of the current process, like /EXECUTE or /CALL-PROCE‐
1829 DURE. (BS2000 only)
1830 break Causes execution to resume after the end of the nearest enclos‐
1832 ing foreach or while. The remaining commands on the current
1833 line are executed. Multi-level breaks are thus possible by
1834 writing them all on one line.
1835 breaksw Causes a break from a switch, resuming after the endsw.
1837 builtins (+)
1839 Prints the names of all builtin commands.
1840 bye (+) A synonym for the logout builtin command. Available only if
1842 the shell was so compiled; see the version shell variable.
1843 case label:
1845 A label in a switch statement as discussed below.
1846 cd [-p] [-l] [-n|-v] [name]
1848 If a directory name is given, changes the shell's working
1849 directory to name. If not, changes to home. If name is `-' it
1850 is interpreted as the previous working directory (see Other
1851 substitutions). (+) If name is not a subdirectory of the cur‐
1852 rent directory (and does not begin with `/', `./' or `../'),
1853 each component of the variable cdpath is checked to see if it
1854 has a subdirectory name. Finally, if all else fails but name
1855 is a shell variable whose value begins with `/', then this is
1856 tried to see if it is a directory.
1857 With -p, prints the final directory stack, just like dirs. The
1859 -l, -n and -v flags have the same effect on cd as on dirs, and
1860 they imply -p. (+)
1861 See also the implicitcd shell variable.
1863 chdir A synonym for the cd builtin command.
1865 complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
1867 Without arguments, lists all completions. With command, lists
1868 completions for command. With command and word etc., defines
1869 completions.
1870 command may be a full command name or a glob-pattern (see File‐
1872 name substitution). It can begin with `-' to indicate that
1873 completion should be used only when command is ambiguous.
1874 word specifies which word relative to the current word is to be
1876 completed, and may be one of the following:
1877 c Current-word completion. pattern is a glob-pattern
1879 which must match the beginning of the current word on
1880 the command line. pattern is ignored when completing
1881 the current word.
1882 C Like c, but includes pattern when completing the cur‐
1883 rent word.
1884 n Next-word completion. pattern is a glob-pattern which
1885 must match the beginning of the previous word on the
1886 command line.
1887 N Like n, but must match the beginning of the word two
1888 before the current word.
1889 p Position-dependent completion. pattern is a numeric
1890 range, with the same syntax used to index shell vari‐
1891 ables, which must include the current word.
1892 list, the list of possible completions, may be one of the fol‐
1894 lowing:
1895 a Aliases
1897 b Bindings (editor commands)
1898 c Commands (builtin or external commands)
1899 C External commands which begin with the supplied
1900 path prefix
1901 d Directories
1902 D Directories which begin with the supplied path pre‐
1903 fix
1904 e Environment variables
1905 f Filenames
1906 F Filenames which begin with the supplied path prefix
1907 g Groupnames
1908 j Jobs
1909 l Limits
1910 n Nothing
1911 s Shell variables
1912 S Signals
1913 t Plain (``text'') files
1914 T Plain (``text'') files which begin with the sup‐
1915 plied path prefix
1916 v Any variables
1917 u Usernames
1918 x Like n, but prints select when list-choices is
1919 used.
1920 X Completions
1921 $var Words from the variable var
1922 (...) Words from the given list
1923 `...` Words from the output of command
1924 select is an optional glob-pattern. If given, words from only
1926 list that match select are considered and the fignore shell
1927 variable is ignored. The last three types of completion may
1928 not have a select pattern, and x uses select as an explanatory
1929 message when the list-choices editor command is used.
1930 suffix is a single character to be appended to a successful
1932 completion. If null, no character is appended. If omitted (in
1933 which case the fourth delimiter can also be omitted), a slash
1934 is appended to directories and a space to other words.
1935 Now for some examples. Some commands take only directories as
1937 arguments, so there's no point completing plain files.
1938 > complete cd 'p/1/d/'
1940 completes only the first word following `cd' (`p/1') with a
1942 directory. p-type completion can also be used to narrow down
1943 command completion:
1944 > co[^D]
1946 complete compress
1947 > complete -co* 'p/0/(compress)/'
1948 > co[^D]
1949 > compress
1950 This completion completes commands (words in position 0, `p/0')
1952 which begin with `co' (thus matching `co*') to `compress' (the
1953 only word in the list). The leading `-' indicates that this
1954 completion is to be used with only ambiguous commands.
1955 > complete find 'n/-user/u/'
1957 is an example of n-type completion. Any word following `find'
1959 and immediately following `-user' is completed from the list of
1960 users.
1961 > complete cc 'c/-I/d/'
1963 demonstrates c-type completion. Any word following `cc' and
1965 beginning with `-I' is completed as a directory. `-I' is not
1966 taken as part of the directory because we used lowercase c.
1967 Different lists are useful with different commands.
1969 > complete alias 'p/1/a/'
1971 > complete man 'p/*/c/'
1972 > complete set 'p/1/s/'
1973 > complete true 'p/1/x:Truth has no options./'
1974 These complete words following `alias' with aliases, `man' with
1976 commands, and `set' with shell variables. `true' doesn't have
1977 any options, so x does nothing when completion is attempted and
1978 prints `Truth has no options.' when completion choices are
1979 listed.
1980 Note that the man example, and several other examples below,
1982 could just as well have used 'c/*' or 'n/*' as 'p/*'.
1983 Words can be completed from a variable evaluated at completion
1985 time,
1986 > complete ftp 'p/1/$hostnames/'
1988 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
1989 > ftp [^D]
1990 rtfm.mit.edu tesla.ee.cornell.edu
1991 > ftp [^C]
1992 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
1993 uunet.uu.net)
1994 > ftp [^D]
1995 rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net
1996 or from a command run at completion time:
1998 > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
2000 > kill -9 [^D]
2001 23113 23377 23380 23406 23429 23529 23530 PID
2002 Note that the complete command does not itself quote its argu‐
2004 ments, so the braces, space and `$' in `{print $1}' must be
2005 quoted explicitly.
2006 One command can have multiple completions:
2008 > complete dbx 'p/2/(core)/' 'p/*/c/'
2010 completes the second argument to `dbx' with the word `core' and
2012 all other arguments with commands. Note that the positional
2013 completion is specified before the next-word completion.
2014 Because completions are evaluated from left to right, if the
2015 next-word completion were specified first it would always match
2016 and the positional completion would never be executed. This is
2017 a common mistake when defining a completion.
2018 The select pattern is useful when a command takes files with
2020 only particular forms as arguments. For example,
2021 > complete cc 'p/*/f:*.[cao]/'
2023 completes `cc' arguments to files ending in only `.c', `.a', or
2025 `.o'. select can also exclude files, using negation of a glob-
2026 pattern as described under Filename substitution. One might
2027 use
2028 > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'
2030 to exclude precious source code from `rm' completion. Of
2032 course, one could still type excluded names manually or over‐
2033 ride the completion mechanism using the complete-word-raw or
2034 list-choices-raw editor commands (q.v.).
2035 The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
2037 respectively, but they use the select argument in a different
2038 way: to restrict completion to files beginning with a particu‐
2039 lar path prefix. For example, the Elm mail program uses `=' as
2040 an abbreviation for one's mail directory. One might use
2041 > complete elm c@=@F:$HOME/Mail/@
2043 to complete `elm -f =' as if it were `elm -f ~/Mail/'. Note
2045 that we used `@' instead of `/' to avoid confusion with the
2046 select argument, and we used `$HOME' instead of `~' because
2047 home directory substitution works at only the beginning of a
2048 word.
2049 suffix is used to add a nonstandard suffix (not space or `/'
2051 for directories) to completed words.
2052 > complete finger 'c/*@/$hostnames/' 'p/1/u/@'
2054 completes arguments to `finger' from the list of users, appends
2056 an `@', and then completes after the `@' from the `hostnames'
2057 variable. Note again the order in which the completions are
2058 specified.
2059 Finally, here's a complex example for inspiration:
2061 > complete find \
2063 'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
2064 ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
2065 'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
2066 'n/-type/(b c d f l p s)/' \
2067 ´c/-/(name newer cpio ncpio exec ok user \
2068 group fstype type atime ctime depth inum \
2069 ls mtime nogroup nouser perm print prune \
2070 size xdev)/' \
2071 'p/*/d/'
2072 This completes words following `-name', `-newer', `-cpio' or
2074 `ncpio' (note the pattern which matches both) to files, words
2075 following `-exec' or `-ok' to commands, words following `user'
2076 and `group' to users and groups respectively and words follow‐
2077 ing `-fstype' or `-type' to members of the given lists. It
2078 also completes the switches themselves from the given list
2079 (note the use of c-type completion) and completes anything not
2080 otherwise completed to a directory. Whew.
2081 Remember that programmed completions are ignored if the word
2083 being completed is a tilde substitution (beginning with `~') or
2084 a variable (beginning with `$'). complete is an experimental
2085 feature, and the syntax may change in future versions of the
2086 shell. See also the uncomplete builtin command.
2087 continue
2089 Continues execution of the nearest enclosing while or foreach.
2090 The rest of the commands on the current line are executed.
2091 default:
2093 Labels the default case in a switch statement. It should come
2094 after all case labels.
2095 dirs [-l] [-n|-v]
2097 dirs -S|-L [filename] (+)
2098 dirs -c (+)
2099 The first form prints the directory stack. The top of the
2100 stack is at the left and the first directory in the stack is
2101 the current directory. With -l, `~' or `~name' in the output
2102 is expanded explicitly to home or the pathname of the home
2103 directory for user name. (+) With -n, entries are wrapped
2104 before they reach the edge of the screen. (+) With -v, entries
2105 are printed one per line, preceded by their stack positions.
2106 (+) If more than one of -n or -v is given, -v takes precedence.
2107 -p is accepted but does nothing.
2108 With -S, the second form saves the directory stack to filename
2110 as a series of cd and pushd commands. With -L, the shell
2111 sources filename, which is presumably a directory stack file
2112 saved by the -S option or the savedirs mechanism. In either
2113 case, dirsfile is used if filename is not given and ~/.cshdirs
2114 is used if dirsfile is unset.
2115 Note that login shells do the equivalent of `dirs -L' on
2117 startup and, if savedirs is set, `dirs -S' before exiting.
2118 Because only ~/.tcshrc is normally sourced before ~/.cshdirs,
2119 dirsfile should be set in ~/.tcshrc rather than ~/.login.
2120 The last form clears the directory stack.
2122 echo [-n] word ...
2124 Writes each word to the shell's standard output, separated by
2125 spaces and terminated with a newline. The echo_style shell
2126 variable may be set to emulate (or not) the flags and escape
2127 sequences of the BSD and/or System V versions of echo; see
2128 echo(1).
2129 echotc [-sv] arg ... (+)
2131 Exercises the terminal capabilities (see termcap(5)) in args.
2132 For example, 'echotc home' sends the cursor to the home posi‐
2133 tion, 'echotc cm 3 10' sends it to column 3 and row 10, and
2134 'echotc ts 0; echo "This is a test."; echotc fs' prints "This
2135 is a test." in the status line.
2136 If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
2138 value of that capability ("yes" or "no" indicating that the
2139 terminal does or does not have that capability). One might use
2140 this to make the output from a shell script less verbose on
2141 slow terminals, or limit command output to the number of lines
2142 on the screen:
2143 > set history=`echotc lines`
2145 > @ history--
2146 Termcap strings may contain wildcards which will not echo cor‐
2148 rectly. One should use double quotes when setting a shell
2149 variable to a terminal capability string, as in the following
2150 example that places the date in the status line:
2151 > set tosl="`echotc ts 0`"
2153 > set frsl="`echotc fs`"
2154 > echo -n "$tosl";date; echo -n "$frsl"
2155 With -s, nonexistent capabilities return the empty string
2157 rather than causing an error. With -v, messages are verbose.
2158 else
2160 end
2161 endif
2162 endsw See the description of the foreach, if, switch, and while
2163 statements below.
2164 eval arg ...
2166 Treats the arguments as input to the shell and executes the
2167 resulting command(s) in the context of the current shell. This
2168 is usually used to execute commands generated as the result of
2169 command or variable substitution, because parsing occurs before
2170 these substitutions. See tset(1) for a sample use of eval.
2171 exec command
2173 Executes the specified command in place of the current shell.
2174 exit [expr]
2176 The shell exits either with the value of the specified expr (an
2177 expression, as described under Expressions) or, without expr,
2178 with the value of the status variable.
2179 fg [%job ...]
2181 Brings the specified jobs (or, without arguments, the current
2182 job) into the foreground, continuing each if it is stopped.
2183 job may be a number, a string, `', `%', `+' or `-' as described
2184 under Jobs. See also the run-fg-editor editor command.
2185 filetest -op file ... (+)
2187 Applies op (which is a file inquiry operator as described under
2188 File inquiry operators) to each file and returns the results as
2189 a space-separated list.
2190 foreach name (wordlist)
2192 ...
2193 end Successively sets the variable name to each member of wordlist
2194 and executes the sequence of commands between this command and
2195 the matching end. (Both foreach and end must appear alone on
2196 separate lines.) The builtin command continue may be used to
2197 continue the loop prematurely and the builtin command break to
2198 terminate it prematurely. When this command is read from the
2199 terminal, the loop is read once prompting with `foreach? ' (or
2200 prompt2) before any statements in the loop are executed. If
2201 you make a mistake typing in a loop at the terminal you can rub
2202 it out.
2203 getspath (+)
2205 Prints the system execution path. (TCF only)
2206 getxvers (+)
2208 Prints the experimental version prefix. (TCF only)
2209 glob wordlist
2211 Like echo, but no `\' escapes are recognized and words are
2212 delimited by null characters in the output. Useful for pro‐
2213 grams which wish to use the shell to filename expand a list of
2214 words.
2215 goto word
2217 word is filename and command-substituted to yield a string of
2218 the form `label'. The shell rewinds its input as much as pos‐
2219 sible, searches for a line of the form `label:', possibly pre‐
2220 ceded by blanks or tabs, and continues execution after that
2221 line.
2222 hashstat
2224 Prints a statistics line indicating how effective the internal
2225 hash table has been at locating commands (and avoiding exec's).
2226 An exec is attempted for each component of the path where the
2227 hash function indicates a possible hit, and in each component
2228 which does not begin with a `/'.
2229 On machines without vfork(2), prints only the number and size
2231 of hash buckets.
2232 history [-hTr] [n]
2234 history -S|-L|-M [filename] (+)
2235 history -c (+)
2236 The first form prints the history event list. If n is given
2237 only the n most recent events are printed or saved. With -h,
2238 the history list is printed without leading numbers. If -T is
2239 specified, timestamps are printed also in comment form. (This
2240 can be used to produce files suitable for loading with 'history
2241 -L' or 'source -h'.) With -r, the order of printing is most
2242 recent first rather than oldest first.
2243 With -S, the second form saves the history list to filename.
2245 If the first word of the savehist shell variable is set to a
2246 number, at most that many lines are saved. If the second word
2247 of savehist is set to `merge', the history list is merged with
2248 the existing history file instead of replacing it (if there is
2249 one) and sorted by time stamp. (+) Merging is intended for an
2250 environment like the X Window System with several shells in
2251 simultaneous use. Currently it succeeds only when the shells
2252 quit nicely one after another.
2253 With -L, the shell appends filename, which is presumably a his‐
2255 tory list saved by the -S option or the savehist mechanism, to
2256 the history list. -M is like -L, but the contents of filename
2257 are merged into the history list and sorted by timestamp. In
2258 either case, histfile is used if filename is not given and
2259 ~/.history is used if histfile is unset. `history -L' is
2260 exactly like 'source -h' except that it does not require a
2261 filename.
2262 Note that login shells do the equivalent of `history -L' on
2264 startup and, if savehist is set, `history -S' before exiting.
2265 Because only ~/.tcshrc is normally sourced before ~/.history,
2266 histfile should be set in ~/.tcshrc rather than ~/.login.
2267 If histlit is set, the first and second forms print and save
2269 the literal (unexpanded) form of the history list.
2270 The last form clears the history list.
2272 hup [command] (+)
2274 With command, runs command such that it will exit on a hangup
2275 signal and arranges for the shell to send it a hangup signal
2276 when the shell exits. Note that commands may set their own
2277 response to hangups, overriding hup. Without an argument
2278 (allowed in only a shell script), causes the shell to exit on a
2279 hangup for the remainder of the script. See also Signal han‐
2280 dling and the nohup builtin command.
2281 if (expr) command
2283 If expr (an expression, as described under Expressions) evalu‐
2284 ates true, then command is executed. Variable substitution on
2285 command happens early, at the same time it does for the rest of
2286 the if command. command must be a simple command, not an
2287 alias, a pipeline, a command list or a parenthesized command
2288 list, but it may have arguments. Input/output redirection
2289 occurs even if expr is false and command is thus not executed;
2290 this is a bug.
2291 if (expr) then
2293 ...
2294 else if (expr2) then
2295 ...
2296 else
2297 ...
2298 endif If the specified expr is true then the commands to the first
2299 else are executed; otherwise if expr2 is true then the commands
2300 to the second else are executed, etc. Any number of else-if
2301 pairs are possible; only one endif is needed. The else part is
2302 likewise optional. (The words else and endif must appear at
2303 the beginning of input lines; the if must appear alone on its
2304 input line or after an else.)
2305 inlib shared-library ... (+)
2307 Adds each shared-library to the current environment. There is
2308 no way to remove a shared library. (Domain/OS only)
2309 jobs [-l]
2311 Lists the active jobs. With -l, lists process IDs in addition
2312 to the normal information. On TCF systems, prints the site on
2313 which each job is executing.
2314 kill [-s signal] %job|pid ...
2316 kill -l The first and second forms sends the specified signal (or, if
2317 none is given, the TERM (terminate) signal) to the specified
2318 jobs or processes. job may be a number, a string, `', `%', `+'
2319 or `-' as described under Jobs. Signals are either given by
2320 number or by name (as given in /usr/include/signal.h, stripped
2321 of the prefix `SIG'). There is no default job; saying just
2322 `kill' does not send a signal to the current job. If the sig‐
2323 nal being sent is TERM (terminate) or HUP (hangup), then the
2324 job or process is sent a CONT (continue) signal as well. The
2325 third form lists the signal names.
2326 limit [-h] [resource [maximum-use]]
2328 Limits the consumption by the current process and each process
2329 it creates to not individually exceed maximum-use on the speci‐
2330 fied resource. If no maximum-use is given, then the current
2331 limit is printed; if no resource is given, then all limitations
2332 are given. If the -h flag is given, the hard limits are used
2333 instead of the current limits. The hard limits impose a ceil‐
2334 ing on the values of the current limits. Only the super-user
2335 may raise the hard limits, but a user may lower or raise the
2336 current limits within the legal range.
2337 Controllable resources currently include (if supported by the
2339 OS):
2340 cputime
2342 the maximum number of cpu-seconds to be used by each
2343 process
2344 filesize
2346 the largest single file which can be created
2347 datasize
2349 the maximum growth of the data+stack region via sbrk(2)
2350 beyond the end of the program text
2351 stacksize
2353 the maximum size of the automatically-extended stack
2354 region
2355 coredumpsize
2357 the size of the largest core dump that will be created
2358 memoryuse
2360 the maximum amount of physical memory a process may have
2361 allocated to it at a given time
2362 heapsize
2364 the maximum amount of memory a process may allocate per
2365 brk() system call
2366 descriptors or openfiles
2368 the maximum number of open files for this process
2369 concurrency
2371 the maximum number of threads for this process
2372 memorylocked
2374 the maximum size which a process may lock into memory
2375 using mlock(2)
2376 maxproc
2378 the maximum number of simultaneous processes for this
2379 user id
2380 sbsize the maximum size of socket buffer usage for this user
2382 maximum-use may be given as a (floating point or integer) num‐
2384 ber followed by a scale factor. For all limits other than
2385 cputime the default scale is `k' or `kilobytes' (1024 bytes); a
2386 scale factor of `m' or `megabytes' may also be used. For
2387 cputime the default scaling is `seconds', while `m' for minutes
2388 or `h' for hours, or a time of the form `mm:ss' giving minutes
2389 and seconds may be used.
2390 For both resource names and scale factors, unambiguous prefixes
2392 of the names suffice.
2393 log (+) Prints the watch shell variable and reports on each user indi‐
2395 cated in watch who is logged in, regardless of when they last
2396 logged in. See also watchlog.
2397 login Terminates a login shell, replacing it with an instance of
2399 /bin/login. This is one way to log off, included for compati‐
2400 bility with sh(1).
2401 logout Terminates a login shell. Especially useful if ignoreeof is
2403 set.
2404 ls-F [-switch ...] [file ...] (+)
2406 Lists files like `ls -F', but much faster. It identifies each
2407 type of special file in the listing with a special character:
2408 / Directory
2410 * Executable
2411 # Block device
2412 % Character device
2413 | Named pipe (systems with named pipes only)
2414 = Socket (systems with sockets only)
2415 @ Symbolic link (systems with symbolic links only)
2416 + Hidden directory (AIX only) or context dependent (HP/UX
2417 only)
2418 : Network special (HP/UX only)
2419 If the listlinks shell variable is set, symbolic links are
2421 identified in more detail (on only systems that have them, of
2422 course):
2423 @ Symbolic link to a non-directory
2425 > Symbolic link to a directory
2426 & Symbolic link to nowhere
2427 listlinks also slows down ls-F and causes partitions holding
2429 files pointed to by symbolic links to be mounted.
2430 If the listflags shell variable is set to `x', `a' or `A', or
2432 any combination thereof (e.g., `xA'), they are used as flags to
2433 ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com‐
2434 bination (e.g., `ls -FxA'). On machines where `ls -C' is not
2435 the default, ls-F acts like `ls -CF', unless listflags contains
2436 an `x', in which case it acts like `ls -xF'. ls-F passes its
2437 arguments to ls(1) if it is given any switches, so `alias ls
2438 ls-F' generally does the right thing.
2439 The ls-F builtin can list files using different colors depend‐
2441 ing on the filetype or extension. See the color tcsh variable
2442 and the LS_COLORS environment variable.
2443 migrate [-site] pid|%jobid ... (+)
2445 migrate -site (+)
2446 The first form migrates the process or job to the site speci‐
2447 fied or the default site determined by the system path. The
2448 second form is equivalent to `migrate -site $$': it migrates
2449 the current process to the specified site. Migrating the shell
2450 itself can cause unexpected behavior, because the shell does
2451 not like to lose its tty. (TCF only)
2452 newgrp [-] group (+)
2454 Equivalent to `exec newgrp'; see newgrp(1). Available only if
2455 the shell was so compiled; see the version shell variable.
2456 nice [+number] [command]
2458 Sets the scheduling priority for the shell to number, or, with‐
2459 out number, to 4. With command, runs command at the appropri‐
2460 ate priority. The greater the number, the less cpu the process
2461 gets. The super-user may specify negative priority by using
2462 `nice -number ...'. Command is always executed in a sub-shell,
2463 and the restrictions placed on commands in simple if statements
2464 apply.
2465 nohup [command]
2467 With command, runs command such that it will ignore hangup sig‐
2468 nals. Note that commands may set their own response to
2469 hangups, overriding nohup. Without an argument (allowed in
2470 only a shell script), causes the shell to ignore hangups for
2471 the remainder of the script. See also Signal handling and the
2472 hup builtin command.
2473 notify [%job ...]
2475 Causes the shell to notify the user asynchronously when the
2476 status of any of the specified jobs (or, without %job, the cur‐
2477 rent job) changes, instead of waiting until the next prompt as
2478 is usual. job may be a number, a string, `', `%', `+' or `-'
2479 as described under Jobs. See also the notify shell variable.
2480 onintr [-|label]
2482 Controls the action of the shell on interrupts. Without argu‐
2483 ments, restores the default action of the shell on interrupts,
2484 which is to terminate shell scripts or to return to the termi‐
2485 nal command input level. With `-', causes all interrupts to be
2486 ignored. With label, causes the shell to execute a `goto
2487 label' when an interrupt is received or a child process termi‐
2488 nates because it was interrupted.
2489 onintr is ignored if the shell is running detached and in sys‐
2491 tem startup files (see FILES), where interrupts are disabled
2492 anyway.
2493 popd [-p] [-l] [-n|-v] [+n]
2495 Without arguments, pops the directory stack and returns to the
2496 new top directory. With a number `+n', discards the n'th entry
2497 in the stack.
2498 Finally, all forms of popd print the final directory stack,
2500 just like dirs. The pushdsilent shell variable can be set to
2501 prevent this and the -p flag can be given to override pushdsi‐
2502 lent. The -l, -n and -v flags have the same effect on popd as
2503 on dirs. (+)
2504 printenv [name] (+)
2506 Prints the names and values of all environment variables or,
2507 with name, the value of the environment variable name.
2508 pushd [-p] [-l] [-n|-v] [name|+n]
2510 Without arguments, exchanges the top two elements of the direc‐
2511 tory stack. If pushdtohome is set, pushd without arguments
2512 does `pushd ~', like cd. (+) With name, pushes the current
2513 working directory onto the directory stack and changes to name.
2514 If name is `-' it is interpreted as the previous working direc‐
2515 tory (see Filename substitution). (+) If dunique is set, pushd
2516 removes any instances of name from the stack before pushing it
2517 onto the stack. (+) With a number `+n', rotates the nth ele‐
2518 ment of the directory stack around to be the top element and
2519 changes to it. If dextract is set, however, `pushd +n'
2520 extracts the nth directory, pushes it onto the top of the stack
2521 and changes to it. (+)
2522 Finally, all forms of pushd print the final directory stack,
2524 just like dirs. The pushdsilent shell variable can be set to
2525 prevent this and the -p flag can be given to override pushdsi‐
2526 lent. The -l, -n and -v flags have the same effect on pushd as
2527 on dirs. (+)
2528 rehash Causes the internal hash table of the contents of the directo‐
2530 ries in the path variable to be recomputed. This is needed if
2531 new commands are added to directories in path while you are
2532 logged in. This should be necessary only if you add commands
2533 to one of your own directories, or if a systems programmer
2534 changes the contents of one of the system directories. Also
2535 flushes the cache of home directories built by tilde expansion.
2536 repeat count command
2538 The specified command, which is subject to the same restric‐
2539 tions as the command in the one line if statement above, is
2540 executed count times. I/O redirections occur exactly once,
2541 even if count is 0.
2542 rootnode //nodename (+)
2544 Changes the rootnode to //nodename, so that `/' will be inter‐
2545 preted as `//nodename'. (Domain/OS only)
2546 sched (+)
2548 sched [+]hh:mm command (+)
2549 sched -n (+)
2550 The first form prints the scheduled-event list. The sched
2551 shell variable may be set to define the format in which the
2552 scheduled-event list is printed. The second form adds command
2553 to the scheduled-event list. For example,
2554 > sched 11:00 echo It\'s eleven o\'clock.
2556 causes the shell to echo `It's eleven o'clock.' at 11 AM. The
2558 time may be in 12-hour AM/PM format
2559 > sched 5pm set prompt='[%h] It\'s after 5; go home: >'
2561 or may be relative to the current time:
2563 > sched +2:15 /usr/lib/uucp/uucico -r1 -sother
2565 A relative time specification may not use AM/PM format. The
2567 third form removes item n from the event list:
2568 > sched
2570 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2571 2 Wed Apr 4 17:00 set prompt=[%h] It's after 5; go
2572 home: >
2573 > sched -2
2574 > sched
2575 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2576 A command in the scheduled-event list is executed just before
2578 the first prompt is printed after the time when the command is
2579 scheduled. It is possible to miss the exact time when the com‐
2580 mand is to be run, but an overdue command will execute at the
2581 next prompt. A command which comes due while the shell is
2582 waiting for user input is executed immediately. However, nor‐
2583 mal operation of an already-running command will not be inter‐
2584 rupted so that a scheduled-event list element may be run.
2585 This mechanism is similar to, but not the same as, the at(1)
2587 command on some Unix systems. Its major disadvantage is that
2588 it may not run a command at exactly the specified time. Its
2589 major advantage is that because sched runs directly from the
2590 shell, it has access to shell variables and other structures.
2591 This provides a mechanism for changing one's working environ‐
2592 ment based on the time of day.
2593 set
2595 set name ...
2596 set name=word ...
2597 set [-r] [-f|-l] name=(wordlist) ... (+)
2598 set name[index]=word ...
2599 set -r (+)
2600 set -r name ... (+)
2601 set -r name=word ... (+)
2602 The first form of the command prints the value of all shell
2603 variables. Variables which contain more than a single word
2604 print as a parenthesized word list. The second form sets name
2605 to the null string. The third form sets name to the single
2606 word. The fourth form sets name to the list of words in
2607 wordlist. In all cases the value is command and filename
2608 expanded. If -r is specified, the value is set read-only. If
2609 -f or -l are specified, set only unique words keeping their
2610 order. -f prefers the first occurrence of a word, and -l the
2611 last. The fifth form sets the index'th component of name to
2612 word; this component must already exist. The sixth form lists
2613 only the names of all shell variables that are read-only. The
2614 seventh form makes name read-only, whether or not it has a
2615 value. The second form sets name to the null string. The
2616 eighth form is the same as the third form, but make name read-
2617 only at the same time.
2618 These arguments can be repeated to set and/or make read-only
2620 multiple variables in a single set command. Note, however,
2621 that variable expansion happens for all arguments before any
2622 setting occurs. Note also that `=' can be adjacent to both
2623 name and word or separated from both by whitespace, but cannot
2624 be adjacent to only one or the other. See also the unset
2625 builtin command.
2626 setenv [name [value]]
2628 Without arguments, prints the names and values of all environ‐
2629 ment variables. Given name, sets the environment variable name
2630 to value or, without value, to the null string.
2631 setpath path (+)
2633 Equivalent to setpath(1). (Mach only)
2634 setspath LOCAL|site|cpu ... (+)
2636 Sets the system execution path. (TCF only)
2637 settc cap value (+)
2639 Tells the shell to believe that the terminal capability cap (as
2640 defined in termcap(5)) has the value value. No sanity checking
2641 is done. Concept terminal users may have to `settc xn no' to
2642 get proper wrapping at the rightmost column.
2643 setty [-d|-q|-x] [-a] [[+|-]mode] (+)
2645 Controls which tty modes (see Terminal management) the shell
2646 does not allow to change. -d, -q or -x tells setty to act on
2647 the `edit', `quote' or `execute' set of tty modes respectively;
2648 without -d, -q or -x, `execute' is used.
2649 Without other arguments, setty lists the modes in the chosen
2651 set which are fixed on (`+mode') or off (`-mode'). The avail‐
2652 able modes, and thus the display, vary from system to system.
2653 With -a, lists all tty modes in the chosen set whether or not
2654 they are fixed. With +mode, -mode or mode, fixes mode on or
2655 off or removes control from mode in the chosen set. For exam‐
2656 ple, `setty +echok echoe' fixes `echok' mode on and allows com‐
2657 mands to turn `echoe' mode on or off, both when the shell is
2658 executing commands.
2659 setxvers [string] (+)
2661 Set the experimental version prefix to string, or removes it if
2662 string is omitted. (TCF only)
2663 shift [variable]
2665 Without arguments, discards argv[1] and shifts the members of
2666 argv to the left. It is an error for argv not to be set or to
2667 have less than one word as value. With variable, performs the
2668 same function on variable.
2669 source [-h] name [args ...]
2671 The shell reads and executes commands from name. The commands
2672 are not placed on the history list. If any args are given,
2673 they are placed in argv. (+) source commands may be nested; if
2674 they are nested too deeply the shell may run out of file
2675 descriptors. An error in a source at any level terminates all
2676 nested source commands. With -h, commands are placed on the
2677 history list instead of being executed, much like `history -L'.
2678 stop %job|pid ...
2680 Stops the specified jobs or processes which are executing in
2681 the background. job may be a number, a string, `', `%', `+' or
2682 `-' as described under Jobs. There is no default job; saying
2683 just `stop' does not stop the current job.
2684 suspend Causes the shell to stop in its tracks, much as if it had been
2686 sent a stop signal with ^Z. This is most often used to stop
2687 shells started by su(1).
2688 switch (string)
2690 case str1:
2691 ...
2692 breaksw
2693 ...
2694 default:
2695 ...
2696 breaksw
2697 endsw Each case label is successively matched, against the specified
2698 string which is first command and filename expanded. The file
2699 metacharacters `*', `?' and `[...]' may be used in the case
2700 labels, which are variable expanded. If none of the labels
2701 match before a `default' label is found, then the execution
2702 begins after the default label. Each case label and the
2703 default label must appear at the beginning of a line. The com‐
2704 mand breaksw causes execution to continue after the endsw.
2705 Otherwise control may fall through case labels and default
2706 labels as in C. If no label matches and there is no default,
2707 execution continues after the endsw.
2708 telltc (+)
2710 Lists the values of all terminal capabilities (see termcap(5)).
2711 termname [terminal type] (+)
2713 Tests if terminal type (or the current value of TERM if no ter‐
2714 minal type is given) has an entry in the hosts termcap(5) or
2715 terminfo(5) database. Prints the terminal type to stdout and
2716 returns 0 if an entry is present otherwise returns 1.
2717 time [command]
2719 Executes command (which must be a simple command, not an alias,
2720 a pipeline, a command list or a parenthesized command list) and
2721 prints a time summary as described under the time variable. If
2722 necessary, an extra shell is created to print the time statis‐
2723 tic when the command completes. Without command, prints a time
2724 summary for the current shell and its children.
2725 umask [value]
2727 Sets the file creation mask to value, which is given in octal.
2728 Common values for the mask are 002, giving all access to the
2729 group and read and execute access to others, and 022, giving
2730 read and execute access to the group and others. Without
2731 value, prints the current file creation mask.
2732 unalias pattern
2734 Removes all aliases whose names match pattern. `unalias *'
2735 thus removes all aliases. It is not an error for nothing to be
2736 unaliased.
2737 uncomplete pattern (+)
2739 Removes all completions whose names match pattern. `uncomplete
2740 *' thus removes all completions. It is not an error for noth‐
2741 ing to be uncompleted.
2742 unhash Disables use of the internal hash table to speed location of
2744 executed programs.
2745 universe universe (+)
2747 Sets the universe to universe. (Masscomp/RTU only)
2748 unlimit [-h] [resource]
2750 Removes the limitation on resource or, if no resource is speci‐
2751 fied, all resource limitations. With -h, the corresponding
2752 hard limits are removed. Only the super-user may do this.
2753 Note that unlimit may not exit successful, since most systems
2754 do not allow descriptors to be unlimited.
2755 unset pattern
2757 Removes all variables whose names match pattern, unless they
2758 are read-only. `unset *' thus removes all variables unless
2759 they are read-only; this is a bad idea. It is not an error for
2760 nothing to be unset.
2761 unsetenv pattern
2763 Removes all environment variables whose names match pattern.
2764 `unsetenv *' thus removes all environment variables; this is a
2765 bad idea. It is not an error for nothing to be unsetenved.
2766 ver [systype [command]] (+)
2768 Without arguments, prints SYSTYPE. With systype, sets SYSTYPE
2769 to systype. With systype and command, executes command under
2770 systype. systype may be `bsd4.3' or `sys5.3'. (Domain/OS
2771 only)
2772 wait The shell waits for all background jobs. If the shell is
2774 interactive, an interrupt will disrupt the wait and cause the
2775 shell to print the names and job numbers of all outstanding
2776 jobs.
2777 warp universe (+)
2779 Sets the universe to universe. (Convex/OS only)
2780 watchlog (+)
2782 An alternate name for the log builtin command (q.v.). Avail‐
2783 able only if the shell was so compiled; see the version shell
2784 variable.
2785 where command (+)
2787 Reports all known instances of command, including aliases,
2788 builtins and executables in path.
2789 which command (+)
2791 Displays the command that will be executed by the shell after
2792 substitutions, path searching, etc. The builtin command is
2793 just like which(1), but it correctly reports tcsh aliases and
2794 builtins and is 10 to 100 times faster. See also the which-
2795 command editor command.
2796 while (expr)
2798 ...
2799 end Executes the commands between the while and the matching end
2800 while expr (an expression, as described under Expressions)
2801 evaluates non-zero. while and end must appear alone on their
2802 input lines. break and continue may be used to terminate or
2803 continue the loop prematurely. If the input is a terminal, the
2804 user is prompted the first time through the loop as with fore‐
2805 ach.
2806 Special aliases (+)
2808 If set, each of these aliases executes automatically at the indicated
2809 time. They are all initially undefined.
2810 beepcmd Runs when the shell wants to ring the terminal bell.
2812 cwdcmd Runs after every change of working directory. For example, if
2814 the user is working on an X window system using xterm(1) and a
2815 re-parenting window manager that supports title bars such as
2816 twm(1) and does
2817 > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd ^G"'
2819 then the shell will change the title of the running xterm(1) to
2821 be the name of the host, a colon, and the full current working
2822 directory. A fancier way to do that is
2823 > alias cwdcmd 'echo -n
2825 "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'
2826 This will put the hostname and working directory on the title
2828 bar but only the hostname in the icon manager menu.
2829 Note that putting a cd, pushd or popd in cwdcmd may cause an
2831 infinite loop. It is the author's opinion that anyone doing so
2832 will get what they deserve.
2833 jobcmd Runs before each command gets executed, or when the command
2835 changes state. This is similar to postcmd, but it does not
2836 print builtins.
2837 > alias jobcmd 'echo -n "^[]2\;\!#^G"'
2839 then executing vi foo.c will put the command string in the
2841 xterm title bar.
2842 helpcommand
2844 Invoked by the run-help editor command. The command name for
2845 which help is sought is passed as sole argument. For example,
2846 if one does
2847 > alias helpcommand '\!:1 --help'
2849 then the help display of the command itself will be invoked,
2851 using the GNU help calling convention. Currently there is no
2852 easy way to account for various calling conventions (e.g., the
2853 customary Unix `-h'), except by using a table of many commands.
2854 periodic
2856 Runs every tperiod minutes. This provides a convenient means
2857 for checking on common but infrequent changes such as new mail.
2858 For example, if one does
2859 > set tperiod = 30
2861 > alias periodic checknews
2862 then the checknews(1) program runs every 30 minutes. If peri‐
2864 odic is set but tperiod is unset or set to 0, periodic behaves
2865 like precmd.
2866 precmd Runs just before each prompt is printed. For example, if one
2868 does
2869 > alias precmd date
2871 then date(1) runs just before the shell prompts for each com‐
2873 mand. There are no limits on what precmd can be set to do, but
2874 discretion should be used.
2875 postcmd Runs before each command gets executed.
2877 > alias postcmd 'echo -n "^[]2\;\!#^G"'
2879 then executing vi foo.c will put the command string in the
2881 xterm title bar.
2882 shell Specifies the interpreter for executable scripts which do not
2884 themselves specify an interpreter. The first word should be a
2885 full path name to the desired interpreter (e.g., `/bin/csh' or
2886 `/usr/local/bin/tcsh').
2887 Special shell variables
2889 The variables described in this section have special meaning to the
2890 shell.
2891 The shell sets addsuffix, argv, autologout, csubstnonl, command,
2893 echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
2894 prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
2895 at startup; they do not change thereafter unless changed by the user.
2896 The shell updates cwd, dirstack, owd and status when necessary, and
2897 sets logout on logout.
2898 The shell synchronizes afsuser, group, home, path, shlvl, term and user
2900 with the environment variables of the same names: whenever the environ‐
2901 ment variable changes the shell changes the corresponding shell vari‐
2902 able to match (unless the shell variable is read-only) and vice versa.
2903 Note that although cwd and PWD have identical meanings, they are not
2904 synchronized in this manner, and that the shell automatically intercon‐
2905 verts the different formats of path and PATH.
2906 addsuffix (+)
2908 If set, filename completion adds `/' to the end of directories
2909 and a space to the end of normal files when they are matched
2910 exactly. Set by default.
2911 afsuser (+)
2913 If set, autologout's autolock feature uses its value instead of
2914 the local username for kerberos authentication.
2915 ampm (+)
2917 If set, all times are shown in 12-hour AM/PM format.
2918 argv The arguments to the shell. Positional parameters are taken
2920 from argv, i.e., `$1' is replaced by `$argv[1]', etc. Set by
2921 default, but usually empty in interactive shells.
2922 autocorrect (+)
2924 If set, the spell-word editor command is invoked automatically
2925 before each completion attempt.
2926 autoexpand (+)
2928 If set, the expand-history editor command is invoked automati‐
2929 cally before each completion attempt.
2930 autolist (+)
2932 If set, possibilities are listed after an ambiguous completion.
2933 If set to `ambiguous', possibilities are listed only when no
2934 new characters are added by completion.
2935 autologout (+)
2937 The first word is the number of minutes of inactivity before
2938 automatic logout. The optional second word is the number of
2939 minutes of inactivity before automatic locking. When the shell
2940 automatically logs out, it prints `auto-logout', sets the vari‐
2941 able logout to `automatic' and exits. When the shell automati‐
2942 cally locks, the user is required to enter his password to con‐
2943 tinue working. Five incorrect attempts result in automatic
2944 logout. Set to `60' (automatic logout after 60 minutes, and no
2945 locking) by default in login and superuser shells, but not if
2946 the shell thinks it is running under a window system (i.e., the
2947 DISPLAY environment variable is set), the tty is a pseudo-tty
2948 (pty) or the shell was not so compiled (see the version shell
2949 variable). See also the afsuser and logout shell variables.
2950 backslash_quote (+)
2952 If set, backslashes (`\') always quote `\', `'', and `"'. This
2953 may make complex quoting tasks easier, but it can cause syntax
2954 errors in csh(1) scripts.
2955 catalog The file name of the message catalog. If set, tcsh use
2957 `tcsh.${catalog}' as a message catalog instead of default
2958 `tcsh'.
2959 cdpath A list of directories in which cd should search for subdirecto‐
2961 ries if they aren't found in the current directory.
2962 color If set, it enables color display for the builtin ls-F and it
2964 passes --color=auto to ls. Alternatively, it can be set to
2965 only ls-F or only ls to enable color to only one command. Set‐
2966 ting it to nothing is equivalent to setting it to (ls-F ls).
2967 colorcat
2969 If set, it enables color escape sequence for NLS message files.
2970 And display colorful NLS messages.
2971 command (+)
2973 If set, the command which was passed to the shell with the -c
2974 flag (q.v.).
2975 complete (+)
2977 If set to `enhance', completion 1) ignores case and 2) consid‐
2978 ers periods, hyphens and underscores (`.', `-' and `_') to be
2979 word separators and hyphens and underscores to be equivalent.
2980 If set to `igncase', the completion becomes case insensitive.
2981 continue (+)
2983 If set to a list of commands, the shell will continue the
2984 listed commands, instead of starting a new one.
2985 continue_args (+)
2987 Same as continue, but the shell will execute:
2988 echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>
2990 correct (+)
2992 If set to `cmd', commands are automatically spelling-corrected.
2993 If set to `complete', commands are automatically completed. If
2994 set to `all', the entire command line is corrected.
2995 csubstnonl (+)
2997 If set, newlines and carriage returns in command substitution
2998 are replaced by spaces. Set by default.
2999 cwd The full pathname of the current directory. See also the
3001 dirstack and owd shell variables.
3002 dextract (+)
3004 If set, `pushd +n' extracts the nth directory from the direc‐
3005 tory stack rather than rotating it to the top.
3006 dirsfile (+)
3008 The default location in which `dirs -S' and `dirs -L' look for
3009 a history file. If unset, ~/.cshdirs is used. Because only
3010 ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
3011 should be set in ~/.tcshrc rather than ~/.login.
3012 dirstack (+)
3014 An array of all the directories on the directory stack.
3015 `$dirstack[1]' is the current working directory, `$dirstack[2]'
3016 the first directory on the stack, etc. Note that the current
3017 working directory is `$dirstack[1]' but `=0' in directory stack
3018 substitutions, etc. One can change the stack arbitrarily by
3019 setting dirstack, but the first element (the current working
3020 directory) is always correct. See also the cwd and owd shell
3021 variables.
3022 dspmbyte (+)
3024 Has an affect iff 'dspm' is listed as part of the version shell
3025 variable. If set to `euc', it enables display and editing EUC-
3026 kanji(Japanese) code. If set to `sjis', it enables display and
3027 editing Shift-JIS(Japanese) code. If set to `big5', it enables
3028 display and editing Big5(Chinese) code. If set to `utf8', it
3029 enables display and editing Utf8(Unicode) code. If set to the
3030 following format, it enables display and editing of original
3031 multi-byte code format:
3032 > set dspmbyte = 0000....(256 bytes)....0000
3034 The table requires just 256 bytes. Each character of 256 char‐
3036 acters corresponds (from left to right) to the ASCII codes
3037 0x00, 0x01, ... 0xff. Each character is set to number 0,1,2
3038 and 3. Each number has the following meaning:
3039 0 ... not used for multi-byte characters.
3040 1 ... used for the first byte of a multi-byte character.
3041 2 ... used for the second byte of a multi-byte character.
3042 3 ... used for both the first byte and second byte of a
3043 multi-byte character.
3044 Example:
3052 If set to `001322', the first character (means 0x00 of the
3053 ASCII code) and second character (means 0x01 of ASCII code) are
3054 set to `0'. Then, it is not used for multi-byte characters.
3055 The 3rd character (0x02) is set to '1', indicating that it is
3056 used for the first byte of a multi-byte character. The 4th
3057 character(0x03) is set '3'. It is used for both the first byte
3058 and the second byte of a multi-byte character. The 5th and 6th
3059 characters (0x04,0x05) are set to '2', indicating that they are
3060 used for the second byte of a multi-byte character.
3061 The GNU fileutils version of ls cannot display multi-byte file‐
3063 names without the -N ( --literal ) option. If you are using
3064 this version, set the second word of dspmbyte to "ls". If not,
3065 for example, "ls-F -l" cannot display multi-byte filenames.
3066 Note:
3068 This variable can only be used if KANJI and DSPMBYTE has been
3069 defined at compile time.
3070 dunique (+)
3072 If set, pushd removes any instances of name from the stack
3073 before pushing it onto the stack.
3074 echo If set, each command with its arguments is echoed just before
3076 it is executed. For non-builtin commands all expansions occur
3077 before echoing. Builtin commands are echoed before command and
3078 filename substitution, because these substitutions are then
3079 done selectively. Set by the -x command line option.
3080 echo_style (+)
3082 The style of the echo builtin. May be set to
3083 bsd Don't echo a newline if the first argument is `-n'.
3085 sysv Recognize backslashed escape sequences in echo strings.
3086 both Recognize both the `-n' flag and backslashed escape
3087 sequences; the default.
3088 none Recognize neither.
3089 Set by default to the local system default. The BSD and System
3091 V options are described in the echo(1) man pages on the appro‐
3092 priate systems.
3093 edit (+)
3095 If set, the command-line editor is used. Set by default in
3096 interactive shells.
3097 ellipsis (+)
3099 If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
3100 shell variable) indicate skipped directories with an ellipsis
3101 (`...') instead of `/<skipped>'.
3102 fignore (+)
3104 Lists file name suffixes to be ignored by completion.
3105 filec In tcsh, completion is always used and this variable is ignored
3107 by default. If edit is unset, then the traditional csh comple‐
3108 tion is used. If set in csh, filename completion is used.
3109 gid (+) The user's real group ID.
3111 group (+)
3113 The user's group name.
3114 histchars
3116 A string value determining the characters used in History sub‐
3117 stitution (q.v.). The first character of its value is used as
3118 the history substitution character, replacing the default char‐
3119 acter `!'. The second character of its value replaces the
3120 character `^' in quick substitutions.
3121 histdup (+)
3123 Controls handling of duplicate entries in the history list. If
3124 set to `all' only unique history events are entered in the his‐
3125 tory list. If set to `prev' and the last history event is the
3126 same as the current command, then the current command is not
3127 entered in the history. If set to `erase' and the same event
3128 is found in the history list, that old event gets erased and
3129 the current one gets inserted. Note that the `prev' and `all'
3130 options renumber history events so there are no gaps.
3131 histfile (+)
3133 The default location in which `history -S' and `history -L'
3134 look for a history file. If unset, ~/.history is used. hist‐
3135 file is useful when sharing the same home directory between
3136 different machines, or when saving separate histories on dif‐
3137 ferent terminals. Because only ~/.tcshrc is normally sourced
3138 before ~/.history, histfile should be set in ~/.tcshrc rather
3139 than ~/.login.
3140 histlit (+)
3142 If set, builtin and editor commands and the savehist mechanism
3143 use the literal (unexpanded) form of lines in the history list.
3144 See also the toggle-literal-history editor command.
3145 history The first word indicates the number of history events to save.
3147 The optional second word (+) indicates the format in which his‐
3148 tory is printed; if not given, `%h\t%T\t%R\n' is used. The
3149 format sequences are described below under prompt; note the
3150 variable meaning of `%R'. Set to `100' by default.
3151 home Initialized to the home directory of the invoker. The filename
3153 expansion of `~' refers to this variable.
3154 ignoreeof
3156 If set to the empty string or `0' and the input device is a
3157 terminal, the end-of-file command (usually generated by the
3158 user by typing `^D' on an empty line) causes the shell to print
3159 `Use "exit" to leave tcsh.' instead of exiting. This prevents
3160 the shell from accidentally being killed. Historically this
3161 setting exited after 26 successive EOF's to avoid infinite
3162 loops. If set to a number n, the shell ignores n - 1 consecu‐
3163 tive end-of-files and exits on the nth. (+) If unset, `1' is
3164 used, i.e., the shell exits on a single `^D'.
3165 implicitcd (+)
3167 If set, the shell treats a directory name typed as a command as
3168 though it were a request to change to that directory. If set
3169 to verbose, the change of directory is echoed to the standard
3170 output. This behavior is inhibited in non-interactive shell
3171 scripts, or for command strings with more than one word.
3172 Changing directory takes precedence over executing a like-named
3173 command, but it is done after alias substitutions. Tilde and
3174 variable expansions work as expected.
3175 inputmode (+)
3177 If set to `insert' or `overwrite', puts the editor into that
3178 input mode at the beginning of each line.
3179 killdup (+)
3181 Controls handling of duplicate entries in the kill ring. If
3182 set to `all' only unique strings are entered in the kill ring.
3183 If set to `prev' and the last killed string is the same as the
3184 current killed string, then the current string is not entered
3185 in the ring. If set to `erase' and the same string is found in
3186 the kill ring, the old string is erased and the current one is
3187 inserted.
3188 killring (+)
3190 Indicates the number of killed strings to keep in memory. Set
3191 to `30' by default. If unset or set to less than `2', the
3192 shell will only keep the most recently killed string. Strings
3193 are put in the killring by the editor commands that delete
3194 (kill) strings of text, e.g. backward-delete-word, kill-line,
3195 etc, as well as the copy-region-as-kill command. The yank edi‐
3196 tor command will yank the most recently killed string into the
3197 command-line, while yank-pop (see Editor commands) can be used
3198 to yank earlier killed strings.
3199 listflags (+)
3201 If set to `x', `a' or `A', or any combination thereof (e.g.,
3202 `xA'), they are used as flags to ls-F, making it act like `ls
3203 -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
3204 `a' shows all files (even if they start with a `.'), `A' shows
3205 all files but `.' and `..', and `x' sorts across instead of
3206 down. If the second word of listflags is set, it is used as
3207 the path to `ls(1)'.
3208 listjobs (+)
3210 If set, all jobs are listed when a job is suspended. If set to
3211 `long', the listing is in long format.
3212 listlinks (+)
3214 If set, the ls-F builtin command shows the type of file to
3215 which each symbolic link points.
3216 listmax (+)
3218 The maximum number of items which the list-choices editor com‐
3219 mand will list without asking first.
3220 listmaxrows (+)
3222 The maximum number of rows of items which the list-choices edi‐
3223 tor command will list without asking first.
3224 loginsh (+)
3226 Set by the shell if it is a login shell. Setting or unsetting
3227 it within a shell has no effect. See also shlvl.
3228 logout (+)
3230 Set by the shell to `normal' before a normal logout, `auto‐
3231 matic' before an automatic logout, and `hangup' if the shell
3232 was killed by a hangup signal (see Signal handling). See also
3233 the autologout shell variable.
3234 mail The names of the files or directories to check for incoming
3236 mail, separated by whitespace, and optionally preceded by a
3237 numeric word. Before each prompt, if 10 minutes have passed
3238 since the last check, the shell checks each file and says `You
3239 have new mail.' (or, if mail contains multiple files, `You have
3240 new mail in name.') if the filesize is greater than zero in
3241 size and has a modification time greater than its access time.
3242 If you are in a login shell, then no mail file is reported
3244 unless it has been modified after the time the shell has
3245 started up, to prevent redundant notifications. Most login
3246 programs will tell you whether or not you have mail when you
3247 log in.
3248 If a file specified in mail is a directory, the shell will
3250 count each file within that directory as a separate message,
3251 and will report `You have n mails.' or `You have n mails in
3252 name.' as appropriate. This functionality is provided primar‐
3253 ily for those systems which store mail in this manner, such as
3254 the Andrew Mail System.
3255 If the first word of mail is numeric it is taken as a different
3257 mail checking interval, in seconds.
3258 Under very rare circumstances, the shell may report `You have
3260 mail.' instead of `You have new mail.'
3261 matchbeep (+)
3263 If set to `never', completion never beeps. If set to
3264 `nomatch', it beeps only when there is no match. If set to
3265 `ambiguous', it beeps when there are multiple matches. If set
3266 to `notunique', it beeps when there is one exact and other
3267 longer matches. If unset, `ambiguous' is used.
3268 nobeep (+)
3270 If set, beeping is completely disabled. See also visiblebell.
3271 noclobber
3273 If set, restrictions are placed on output redirection to insure
3274 that files are not accidentally destroyed and that `>>' redi‐
3275 rections refer to existing files, as described in the
3276 Input/output section.
3277 noding If set, disable the printing of `DING!' in the prompt time
3279 specifiers at the change of hour.
3280 noglob If set, Filename substitution and Directory stack substitution
3282 (q.v.) are inhibited. This is most useful in shell scripts
3283 which do not deal with filenames, or after a list of filenames
3284 has been obtained and further expansions are not desirable.
3285 nokanji (+)
3287 If set and the shell supports Kanji (see the version shell
3288 variable), it is disabled so that the meta key can be used.
3289 nonomatch
3291 If set, a Filename substitution or Directory stack substitution
3292 (q.v.) which does not match any existing files is left
3293 untouched rather than causing an error. It is still an error
3294 for the substitution to be malformed, e.g., `echo [' still
3295 gives an error.
3296 nostat (+)
3298 A list of directories (or glob-patterns which match directo‐
3299 ries; see Filename substitution) that should not be stat(2)ed
3300 during a completion operation. This is usually used to exclude
3301 directories which take too much time to stat(2), for example
3302 /afs.
3303 notify If set, the shell announces job completions asynchronously.
3305 The default is to present job completions just before printing
3306 a prompt.
3307 oid (+) The user's real organization ID. (Domain/OS only)
3309 owd (+) The old working directory, equivalent to the `-' used by cd and
3311 pushd. See also the cwd and dirstack shell variables.
3312 path A list of directories in which to look for executable commands.
3314 A null word specifies the current directory. If there is no
3315 path variable then only full path names will execute. path is
3316 set by the shell at startup from the PATH environment variable
3317 or, if PATH does not exist, to a system-dependent default some‐
3318 thing like `(/usr/local/bin /usr/bsd /bin /usr/bin .)'. The
3319 shell may put `.' first or last in path or omit it entirely
3320 depending on how it was compiled; see the version shell vari‐
3321 able. A shell which is given neither the -c nor the -t option
3322 hashes the contents of the directories in path after reading
3323 ~/.tcshrc and each time path is reset. If one adds a new com‐
3324 mand to a directory in path while the shell is active, one may
3325 need to do a rehash for the shell to find it.
3326 printexitvalue (+)
3328 If set and an interactive program exits with a non-zero status,
3329 the shell prints `Exit status'.
3330 prompt The string which is printed before reading each command from
3332 the terminal. prompt may include any of the following format‐
3333 ting sequences (+), which are replaced by the given informa‐
3334 tion:
3335 %/ The current working directory.
3337 %~ The current working directory, but with one's home direc‐
3338 tory represented by `~' and other users' home directories
3339 represented by `~user' as per Filename substitution.
3340 `~user' substitution happens only if the shell has already
3341 used `~user' in a pathname in the current session.
3342 %c[[0]n], %.[[0]n]
3343 The trailing component of the current working directory, or
3344 n trailing components if a digit n is given. If n begins
3345 with `0', the number of skipped components precede the
3346 trailing component(s) in the format `/<skipped>trailing'.
3347 If the ellipsis shell variable is set, skipped components
3348 are represented by an ellipsis so the whole becomes
3349 `...trailing'. `~' substitution is done as in `%~' above,
3350 but the `~' component is ignored when counting trailing
3351 components.
3352 %C Like %c, but without `~' substitution.
3353 %h, %!, !
3354 The current history event number.
3355 %M The full hostname.
3356 %m The hostname up to the first `.'.
3357 %S (%s)
3358 Start (stop) standout mode.
3359 %B (%b)
3360 Start (stop) boldfacing mode.
3361 %U (%u)
3362 Start (stop) underline mode.
3363 %t, %@
3364 The time of day in 12-hour AM/PM format.
3365 %T Like `%t', but in 24-hour format (but see the ampm shell
3366 variable).
3367 %p The `precise' time of day in 12-hour AM/PM format, with
3368 seconds.
3369 %P Like `%p', but in 24-hour format (but see the ampm shell
3370 variable).
3371 \c c is parsed as in bindkey.
3372 ^c c is parsed as in bindkey.
3373 %% A single `%'.
3374 %n The user name.
3375 %j The number of jobs.
3376 %d The weekday in `Day' format.
3377 %D The day in `dd' format.
3378 %w The month in `Mon' format.
3379 %W The month in `mm' format.
3380 %y The year in `yy' format.
3381 %Y The year in `yyyy' format.
3382 %l The shell's tty.
3383 %L Clears from the end of the prompt to end of the display or
3384 the end of the line.
3385 %$ Expands the shell or environment variable name immediately
3386 after the `$'.
3387 %# `>' (or the first character of the promptchars shell vari‐
3388 able) for normal users, `#' (or the second character of
3389 promptchars) for the superuser.
3390 %{string%}
3391 Includes string as a literal escape sequence. It should be
3392 used only to change terminal attributes and should not move
3393 the cursor location. This cannot be the last sequence in
3394 prompt.
3395 %? The return code of the command executed just before the
3396 prompt.
3397 %R In prompt2, the status of the parser. In prompt3, the cor‐
3398 rected string. In history, the history string.
3399 `%B', `%S', `%U' and `%{string%}' are available in only eight-
3401 bit-clean shells; see the version shell variable.
3402 The bold, standout and underline sequences are often used to
3404 distinguish a superuser shell. For example,
3405 > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
3407 tut [37] [2:54pm] [/usr/accts/sys] you rang? _
3408 If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
3410 set, then print `DING!' on the change of hour (i.e, `:00' min‐
3411 utes) instead of the actual time.
3412 Set by default to `%# ' in interactive shells.
3414 prompt2 (+)
3416 The string with which to prompt in while and foreach loops and
3417 after lines ending in `\'. The same format sequences may be
3418 used as in prompt (q.v.); note the variable meaning of `%R'.
3419 Set by default to `%R? ' in interactive shells.
3420 prompt3 (+)
3422 The string with which to prompt when confirming automatic
3423 spelling correction. The same format sequences may be used as
3424 in prompt (q.v.); note the variable meaning of `%R'. Set by
3425 default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.
3426 promptchars (+)
3428 If set (to a two-character string), the `%#' formatting
3429 sequence in the prompt shell variable is replaced with the
3430 first character for normal users and the second character for
3431 the superuser.
3432 pushdtohome (+)
3434 If set, pushd without arguments does `pushd ~', like cd.
3435 pushdsilent (+)
3437 If set, pushd and popd do not print the directory stack.
3438 recexact (+)
3440 If set, completion completes on an exact match even if a longer
3441 match is possible.
3442 recognize_only_executables (+)
3444 If set, command listing displays only files in the path that
3445 are executable. Slow.
3446 rmstar (+)
3448 If set, the user is prompted before `rm *' is executed.
3449 rprompt (+)
3451 The string to print on the right-hand side of the screen (after
3452 the command input) when the prompt is being displayed on the
3453 left. It recognizes the same formatting characters as prompt.
3454 It will automatically disappear and reappear as necessary, to
3455 ensure that command input isn't obscured, and will appear only
3456 if the prompt, command input, and itself will fit together on
3457 the first line. If edit isn't set, then rprompt will be
3458 printed after the prompt and before the command input.
3459 savedirs (+)
3461 If set, the shell does `dirs -S' before exiting. If the first
3462 word is set to a number, at most that many directory stack
3463 entries are saved.
3464 savehist
3466 If set, the shell does `history -S' before exiting. If the
3467 first word is set to a number, at most that many lines are
3468 saved. (The number must be less than or equal to history.) If
3469 the second word is set to `merge', the history list is merged
3470 with the existing history file instead of replacing it (if
3471 there is one) and sorted by time stamp and the most recent
3472 events are retained. (+)
3473 sched (+)
3475 The format in which the sched builtin command prints scheduled
3476 events; if not given, `%h\t%T\t%R\n' is used. The format
3477 sequences are described above under prompt; note the variable
3478 meaning of `%R'.
3479 shell The file in which the shell resides. This is used in forking
3481 shells to interpret files which have execute bits set, but
3482 which are not executable by the system. (See the description
3483 of Builtin and non-builtin command execution.) Initialized to
3484 the (system-dependent) home of the shell.
3485 shlvl (+)
3487 The number of nested shells. Reset to 1 in login shells. See
3488 also loginsh.
3489 status The status returned by the last command. If it terminated
3491 abnormally, then 0200 is added to the status. Builtin commands
3492 which fail return exit status `1', all other builtin commands
3493 return status `0'.
3494 symlinks (+)
3496 Can be set to several different values to control symbolic link
3497 (`symlink') resolution:
3498 If set to `chase', whenever the current directory changes to a
3500 directory containing a symbolic link, it is expanded to the
3501 real name of the directory to which the link points. This does
3502 not work for the user's home directory; this is a bug.
3503 If set to `ignore', the shell tries to construct a current
3505 directory relative to the current directory before the link was
3506 crossed. This means that cding through a symbolic link and
3507 then `cd ..'ing returns one to the original directory. This
3508 affects only builtin commands and filename completion.
3509 If set to `expand', the shell tries to fix symbolic links by
3511 actually expanding arguments which look like path names. This
3512 affects any command, not just builtins. Unfortunately, this
3513 does not work for hard-to-recognize filenames, such as those
3514 embedded in command options. Expansion may be prevented by
3515 quoting. While this setting is usually the most convenient, it
3516 is sometimes misleading and sometimes confusing when it fails
3517 to recognize an argument which should be expanded. A compro‐
3518 mise is to use `ignore' and use the editor command normalize-
3519 path (bound by default to ^X-n) when necessary.
3520 Some examples are in order. First, let's set up some play
3522 directories:
3523 > cd /tmp
3525 > mkdir from from/src to
3526 > ln -s from/src to/dst
3527 Here's the behavior with symlinks unset,
3529 > cd /tmp/to/dst; echo $cwd
3531 /tmp/to/dst
3532 > cd ..; echo $cwd
3533 /tmp/from
3534 here's the behavior with symlinks set to `chase',
3536 > cd /tmp/to/dst; echo $cwd
3538 /tmp/from/src
3539 > cd ..; echo $cwd
3540 /tmp/from
3541 here's the behavior with symlinks set to `ignore',
3543 > cd /tmp/to/dst; echo $cwd
3545 /tmp/to/dst
3546 > cd ..; echo $cwd
3547 /tmp/to
3548 and here's the behavior with symlinks set to `expand'.
3550 > cd /tmp/to/dst; echo $cwd
3552 /tmp/to/dst
3553 > cd ..; echo $cwd
3554 /tmp/to
3555 > cd /tmp/to/dst; echo $cwd
3556 /tmp/to/dst
3557 > cd ".."; echo $cwd
3558 /tmp/from
3559 > /bin/echo ..
3560 /tmp/to
3561 > /bin/echo ".."
3562 ..
3563 Note that `expand' expansion 1) works just like `ignore' for
3565 builtins like cd, 2) is prevented by quoting, and 3) happens
3566 before filenames are passed to non-builtin commands.
3567 tcsh (+)
3569 The version number of the shell in the format `R.VV.PP', where
3570 `R' is the major release number, `VV' the current version and
3571 `PP' the patchlevel.
3572 term The terminal type. Usually set in ~/.login as described under
3574 Startup and shutdown.
3575 time If set to a number, then the time builtin (q.v.) executes auto‐
3577 matically after each command which takes more than that many
3578 CPU seconds. If there is a second word, it is used as a format
3579 string for the output of the time builtin. (u) The following
3580 sequences may be used in the format string:
3581 %U The time the process spent in user mode in cpu seconds.
3583 %S The time the process spent in kernel mode in cpu seconds.
3584 %E The elapsed (wall clock) time in seconds.
3585 %P The CPU percentage computed as (%U + %S) / %E.
3586 %W Number of times the process was swapped.
3587 %X The average amount in (shared) text space used in Kbytes.
3588 %D The average amount in (unshared) data/stack space used in
3589 Kbytes.
3590 %K The total space used (%X + %D) in Kbytes.
3591 %M The maximum memory the process had in use at any time in
3592 Kbytes.
3593 %F The number of major page faults (page needed to be brought
3594 from disk).
3595 %R The number of minor page faults.
3596 %I The number of input operations.
3597 %O The number of output operations.
3598 %r The number of socket messages received.
3599 %s The number of socket messages sent.
3600 %k The number of signals received.
3601 %w The number of voluntary context switches (waits).
3602 %c The number of involuntary context switches.
3603 Only the first four sequences are supported on systems without
3605 BSD resource limit functions. The default time format is `%Uu
3606 %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
3607 resource usage reporting and `%Uu %Ss %E %P' for systems that
3608 do not.
3609 Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail‐
3611 able, but the following additional sequences are:
3612 %Y The number of system calls performed.
3614 %Z The number of pages which are zero-filled on demand.
3615 %i The number of times a process's resident set size was
3616 increased by the kernel.
3617 %d The number of times a process's resident set size was
3618 decreased by the kernel.
3619 %l The number of read system calls performed.
3620 %m The number of write system calls performed.
3621 %p The number of reads from raw disk devices.
3622 %q The number of writes to raw disk devices.
3623 and the default time format is `%Uu %Ss %E %P %I+%Oio
3625 %Fpf+%Ww'. Note that the CPU percentage can be higher than
3626 100% on multi-processors.
3627 tperiod (+)
3629 The period, in minutes, between executions of the periodic spe‐
3630 cial alias.
3631 tty (+) The name of the tty, or empty if not attached to one.
3633 uid (+) The user's real user ID.
3635 user The user's login name.
3637 verbose If set, causes the words of each command to be printed, after
3639 history substitution (if any). Set by the -v command line
3640 option.
3641 version (+)
3643 The version ID stamp. It contains the shell's version number
3644 (see tcsh), origin, release date, vendor, operating system and
3645 machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
3646 list of options which were set at compile time. Options which
3647 are set by default in the distribution are noted.
3648 8b The shell is eight bit clean; default
3650 7b The shell is not eight bit clean
3651 wide The shell is multibyte encoding clean (like UTF-8)
3652 nls The system's NLS is used; default for systems with NLS
3653 lf Login shells execute /etc/csh.login before instead of
3654 after /etc/csh.cshrc and ~/.login before instead of after
3655 ~/.tcshrc and ~/.history.
3656 dl `.' is put last in path for security; default
3657 nd `.' is omitted from path for security
3658 vi vi-style editing is the default rather than emacs
3659 dtr Login shells drop DTR when exiting
3660 bye bye is a synonym for logout and log is an alternate name
3661 for watchlog
3662 al autologout is enabled; default
3663 kan Kanji is used if appropriate according to locale set‐
3664 tings, unless the nokanji shell variable is set
3665 sm The system's malloc(3) is used
3666 hb The `#!<program> <args>' convention is emulated when exe‐
3667 cuting shell scripts
3668 ng The newgrp builtin is available
3669 rh The shell attempts to set the REMOTEHOST environment
3670 variable
3671 afs The shell verifies your password with the kerberos server
3672 if local authentication fails. The afsuser shell vari‐
3673 able or the AFSUSER environment variable override your
3674 local username if set.
3675 An administrator may enter additional strings to indicate dif‐
3677 ferences in the local version.
3678 visiblebell (+)
3680 If set, a screen flash is used rather than the audible bell.
3681 See also nobeep.
3682 watch (+)
3684 A list of user/terminal pairs to watch for logins and logouts.
3685 If either the user is `any' all terminals are watched for the
3686 given user and vice versa. Setting watch to `(any any)'
3687 watches all users and terminals. For example,
3688 set watch = (george ttyd1 any console $user any)
3690 reports activity of the user `george' on ttyd1, any user on the
3692 console, and oneself (or a trespasser) on any terminal.
3693 Logins and logouts are checked every 10 minutes by default, but
3695 the first word of watch can be set to a number to check every
3696 so many minutes. For example,
3697 set watch = (1 any any)
3699 reports any login/logout once every minute. For the impatient,
3701 the log builtin command triggers a watch report at any time.
3702 All current logins are reported (as with the log builtin) when
3703 watch is first set.
3704 The who shell variable controls the format of watch reports.
3706 who (+) The format string for watch messages. The following sequences
3708 are replaced by the given information:
3709 %n The name of the user who logged in/out.
3711 %a The observed action, i.e., `logged on', `logged off' or
3712 `replaced olduser on'.
3713 %l The terminal (tty) on which the user logged in/out.
3714 %M The full hostname of the remote host, or `local' if the
3715 login/logout was from the local host.
3716 %m The hostname of the remote host up to the first `.'. The
3717 full name is printed if it is an IP address or an X Window
3718 System display.
3719 %M and %m are available on only systems that store the remote
3721 hostname in /etc/utmp. If unset, `%n has %a %l from %m.' is
3722 used, or `%n has %a %l.' on systems which don't store the
3723 remote hostname.
3724 wordchars (+)
3726 A list of non-alphanumeric characters to be considered part of
3727 a word by the forward-word, backward-word etc., editor com‐
3728 mands. If unset, `*?_-.[]~=' is used.
3729
3731 AFSUSER (+)
3732 Equivalent to the afsuser shell variable.
3733 COLUMNS The number of columns in the terminal. See Terminal manage‐
3735 ment.
3736 DISPLAY Used by X Window System (see X(1)). If set, the shell does not
3738 set autologout (q.v.).
3739 EDITOR The pathname to a default editor. See also the VISUAL environ‐
3741 ment variable and the run-fg-editor editor command.
3742 GROUP (+)
3744 Equivalent to the group shell variable.
3745 HOME Equivalent to the home shell variable.
3747 HOST (+)
3749 Initialized to the name of the machine on which the shell is
3750 running, as determined by the gethostname(2) system call.
3751 HOSTTYPE (+)
3753 Initialized to the type of machine on which the shell is run‐
3754 ning, as determined at compile time. This variable is obsolete
3755 and will be removed in a future version.
3756 HPATH (+)
3758 A colon-separated list of directories in which the run-help
3759 editor command looks for command documentation.
3760 LANG Gives the preferred character environment. See Native Language
3762 System support.
3763 LC_CTYPE
3765 If set, only ctype character handling is changed. See Native
3766 Language System support.
3767 LINES The number of lines in the terminal. See Terminal management.
3769 LS_COLORS
3771 The format of this variable is reminiscent of the termcap(5)
3772 file format; a colon-separated list of expressions of the form
3773 "xx=string", where "xx" is a two-character variable name. The
3774 variables with their associated defaults are:
3775 no 0 Normal (non-filename) text
3777 fi 0 Regular file
3778 di 01;34 Directory
3779 ln 01;36 Symbolic link
3780 pi 33 Named pipe (FIFO)
3781 so 01;35 Socket
3782 do 01;35 Door
3783 bd 01;33 Block device
3784 cd 01;32 Character device
3785 ex 01;32 Executable file
3786 mi (none) Missing file (defaults to fi)
3787 or (none) Orphaned symbolic link (defaults to ln)
3788 lc ^[[ Left code
3789 rc m Right code
3790 ec (none) End code (replaces lc+no+rc)
3791 You need to include only the variables you want to change from
3793 the default.
3794 File names can also be colorized based on filename extension.
3796 This is specified in the LS_COLORS variable using the syntax
3797 "*ext=string". For example, using ISO 6429 codes, to color all
3798 C-language source files blue you would specify "*.c=34". This
3799 would color all files ending in .c in blue (34) color.
3800 Control characters can be written either in C-style-escaped
3802 notation, or in stty-like ^-notation. The C-style notation
3803 adds ^[ for Escape, _ for a normal space character, and ? for
3804 Delete. In addition, the ^[ escape character can be used to
3805 override the default interpretation of ^[, ^, : and =.
3806 Each file will be written as <lc> <color-code> <rc> <filename>
3808 <ec>. If the <ec> code is undefined, the sequence <lc> <no>
3809 <rc> will be used instead. This is generally more convenient
3810 to use, but less general. The left, right and end codes are
3811 provided so you don't have to type common parts over and over
3812 again and to support weird terminals; you will generally not
3813 need to change them at all unless your terminal does not use
3814 ISO 6429 color sequences but a different system.
3815 If your terminal does use ISO 6429 color codes, you can compose
3817 the type codes (i.e., all except the lc, rc, and ec codes) from
3818 numerical commands separated by semicolons. The most common
3819 commands are:
3820 0 to restore default color
3822 1 for brighter colors
3823 4 for underlined text
3824 5 for flashing text
3825 30 for black foreground
3826 31 for red foreground
3827 32 for green foreground
3828 33 for yellow (or brown) foreground
3829 34 for blue foreground
3830 35 for purple foreground
3831 36 for cyan foreground
3832 37 for white (or gray) foreground
3833 40 for black background
3834 41 for red background
3835 42 for green background
3836 43 for yellow (or brown) background
3837 44 for blue background
3838 45 for purple background
3839 46 for cyan background
3840 47 for white (or gray) background
3841 Not all commands will work on all systems or display devices.
3843 A few terminal programs do not recognize the default end code
3845 properly. If all text gets colorized after you do a directory
3846 listing, try changing the no and fi codes from 0 to the numeri‐
3847 cal codes for your standard fore- and background colors.
3848 MACHTYPE (+)
3850 The machine type (microprocessor class or machine model), as
3851 determined at compile time.
3852 NOREBIND (+)
3854 If set, printable characters are not rebound to self-insert-
3855 command. See Native Language System support.
3856 OSTYPE (+)
3858 The operating system, as determined at compile time.
3859 PATH A colon-separated list of directories in which to look for exe‐
3861 cutables. Equivalent to the path shell variable, but in a dif‐
3862 ferent format.
3863 PWD (+) Equivalent to the cwd shell variable, but not synchronized to
3865 it; updated only after an actual directory change.
3866 REMOTEHOST (+)
3868 The host from which the user has logged in remotely, if this is
3869 the case and the shell is able to determine it. Set only if
3870 the shell was so compiled; see the version shell variable.
3871 SHLVL (+)
3873 Equivalent to the shlvl shell variable.
3874 SYSTYPE (+)
3876 The current system type. (Domain/OS only)
3877 TERM Equivalent to the term shell variable.
3879 TERMCAP The terminal capability string. See Terminal management.
3881 USER Equivalent to the user shell variable.
3883 VENDOR (+)
3885 The vendor, as determined at compile time.
3886 VISUAL The pathname to a default full-screen editor. See also the
3888 EDITOR environment variable and the run-fg-editor editor com‐
3889 mand.
3890
3892 /etc/csh.cshrc Read first by every shell. ConvexOS, Stellix and Intel
3893 use /etc/cshrc and NeXTs use /etc/cshrc.std. A/UX,
3894 AMIX, Cray and IRIX have no equivalent in csh(1), but
3895 read this file in tcsh anyway. Solaris 2.x does not
3896 have it either, but tcsh reads /etc/.cshrc. (+)
3897 /etc/csh.login Read by login shells after /etc/csh.cshrc. ConvexOS,
3898 Stellix and Intel use /etc/login, NeXTs use
3899 /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
3900 AMIX, Cray and IRIX use /etc/cshrc.
3901 ~/.tcshrc (+) Read by every shell after /etc/csh.cshrc or its equiva‐
3902 lent.
3903 ~/.cshrc Read by every shell, if ~/.tcshrc doesn't exist, after
3904 /etc/csh.cshrc or its equivalent. This manual uses
3905 `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
3906 found, ~/.cshrc'.
3907 ~/.history Read by login shells after ~/.tcshrc if savehist is
3908 set, but see also histfile.
3909 ~/.login Read by login shells after ~/.tcshrc or ~/.history.
3910 The shell may be compiled to read ~/.login before
3911 instead of after ~/.tcshrc and ~/.history; see the ver‐
3912 sion shell variable.
3913 ~/.cshdirs (+) Read by login shells after ~/.login if savedirs is set,
3914 but see also dirsfile.
3915 /etc/csh.logout Read by login shells at logout. ConvexOS, Stellix and
3916 Intel use /etc/logout and NeXTs use /etc/logout.std.
3917 A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
3918 but read this file in tcsh anyway. Solaris 2.x does
3919 not have it either, but tcsh reads /etc/.logout. (+)
3920 ~/.logout Read by login shells at logout after /etc/csh.logout or
3921 its equivalent.
3922 /bin/sh Used to interpret shell scripts not starting with a
3923 `#'.
3924 /tmp/sh* Temporary file for `<<'.
3925 /etc/passwd Source of home directories for `~name' substitutions.
3926 The order in which startup files are read may differ if the shell was
3928 so compiled; see Startup and shutdown and the version shell variable.
3929
3931 This manual describes tcsh as a single entity, but experienced csh(1)
3932 users will want to pay special attention to tcsh's new features.
3933 A command-line editor, which supports GNU Emacs or vi(1)-style key
3935 bindings. See The command-line editor and Editor commands.
3936 Programmable, interactive word completion and listing. See Completion
3938 and listing and the complete and uncomplete builtin commands.
3939 Spelling correction (q.v.) of filenames, commands and variables.
3941 Editor commands (q.v.) which perform other useful functions in the mid‐
3943 dle of typed commands, including documentation lookup (run-help), quick
3944 editor restarting (run-fg-editor) and command resolution (which-com‐
3945 mand).
3946 An enhanced history mechanism. Events in the history list are time-
3948 stamped. See also the history command and its associated shell vari‐
3949 ables, the previously undocumented `#' event specifier and new modi‐
3950 fiers under History substitution, the *-history, history-search-*, i-
3951 search-*, vi-search-* and toggle-literal-history editor commands and
3952 the histlit shell variable.
3953 Enhanced directory parsing and directory stack handling. See the cd,
3955 pushd, popd and dirs commands and their associated shell variables, the
3956 description of Directory stack substitution, the dirstack, owd and sym‐
3957 links shell variables and the normalize-command and normalize-path edi‐
3958 tor commands.
3959 Negation in glob-patterns. See Filename substitution.
3961 New File inquiry operators (q.v.) and a filetest builtin which uses
3963 them.
3964 A variety of Automatic, periodic and timed events (q.v.) including
3966 scheduled events, special aliases, automatic logout and terminal lock‐
3967 ing, command timing and watching for logins and logouts.
3968 Support for the Native Language System (see Native Language System sup‐
3970 port), OS variant features (see OS variant support and the echo_style
3971 shell variable) and system-dependent file locations (see FILES).
3972 Extensive terminal-management capabilities. See Terminal management.
3974 New builtin commands including builtins, hup, ls-F, newgrp, printenv,
3976 which and where (q.v.).
3977 New variables that make useful information easily available to the
3979 shell. See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version
3980 shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
3981 environment variables.
3982 A new syntax for including useful information in the prompt string (see
3984 prompt). and special prompts for loops and spelling correction (see
3985 prompt2 and prompt3).
3986 Read-only variables. See Variable substitution.
3988
3990 When a suspended command is restarted, the shell prints the directory
3991 it started in if this is different from the current directory. This
3992 can be misleading (i.e., wrong) as the job may have changed directories
3993 internally.
3994 Shell builtin functions are not stoppable/restartable. Command
3996 sequences of the form `a ; b ; c' are also not handled gracefully when
3997 stopping is attempted. If you suspend `b', the shell will then immedi‐
3998 ately execute `c'. This is especially noticeable if this expansion
3999 results from an alias. It suffices to place the sequence of commands
4000 in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.
4001 Control over tty output after processes are started is primitive; per‐
4003 haps this will inspire someone to work on a good virtual terminal
4004 interface. In a virtual terminal interface much more interesting
4005 things could be done with output control.
4006 Alias substitution is most often used to clumsily simulate shell proce‐
4008 dures; shell procedures should be provided rather than aliases.
4009 Commands within loops are not placed in the history list. Control
4011 structures should be parsed rather than being recognized as built-in
4012 commands. This would allow control commands to be placed anywhere, to
4013 be combined with `|', and to be used with `&' and `;' metasyntax.
4014 foreach doesn't ignore here documents when looking for its end.
4016 It should be possible to use the `:' modifiers on the output of command
4018 substitutions.
4019 The screen update for lines longer than the screen width is very poor
4021 if the terminal cannot move the cursor up (i.e., terminal type `dumb').
4022 HPATH and NOREBIND don't need to be environment variables.
4024 Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
4026 `~' are not negated correctly.
4027 The single-command form of if does output redirection even if the
4029 expression is false and the command is not executed.
4030 ls-F includes file identification characters when sorting filenames and
4032 does not handle control characters in filenames well. It cannot be
4033 interrupted.
4034 Command substitution supports multiple commands and conditions, but not
4036 cycles or backward gotos.
4037 Report bugs at http://bugs.gw.com/, preferably with fixes. If you want
4039 to help maintain and test tcsh, send mail to tcsh-request@mx.gw.com
4040 with the text `subscribe tcsh' on a line by itself in the body.
4041
4043 In 1964, DEC produced the PDP-6. The PDP-10 was a later re-implementa‐
4044 tion. It was re-christened the DECsystem-10 in 1970 or so when DEC
4045 brought out the second model, the KI10.
4046 TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
4048 think tank) in 1972 as an experiment in demand-paged virtual memory
4049 operating systems. They built a new pager for the DEC PDP-10 and cre‐
4050 ated the OS to go with it. It was extremely successful in academia.
4051 In 1975, DEC brought out a new model of the PDP-10, the KL10; they
4053 intended to have only a version of TENEX, which they had licensed from
4054 BBN, for the new box. They called their version TOPS-20 (their capi‐
4055 talization is trademarked). A lot of TOPS-10 users (`The OPerating
4056 System for PDP-10') objected; thus DEC found themselves supporting two
4057 incompatible systems on the same hardware--but then there were 6 on the
4058 PDP-11!
4059 TENEX, and TOPS-20 to version 3, had command completion via a user-
4061 code-level subroutine library called ULTCMD. With version 3, DEC moved
4062 all that capability and more into the monitor (`kernel' for you Unix
4063 types), accessed by the COMND% JSYS (`Jump to SYStem' instruction, the
4064 supervisor call mechanism [are my IBM roots also showing?]).
4065 The creator of tcsh was impressed by this feature and several others of
4067 TENEX and TOPS-20, and created a version of csh which mimicked them.
4068
4070 Words can be no longer than 1024 characters.
4071 The system limits argument lists to 10240 characters.
4073 The number of arguments to a command which involves filename expansion
4075 is limited to 1/6th the number of characters allowed in an argument
4076 list.
4077 Command substitutions may substitute no more characters than are
4079 allowed in an argument list.
4080 To detect looping, the shell restricts the number of alias substitu‐
4082 tions on a single line to 20.
4083
4085 csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
4086 tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
4087 pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
4088 malloc(3), setlocale(3), tty(4), a.out(5), termcap(5), environ(7),
4089 termio(7), Introduction to the C Shell
4090
4092 This manual documents tcsh 6.14.00 (Astron) 2005-03-25.
4093
4095 William Joy
4096 Original author of csh(1)
4097 J.E. Kulp, IIASA, Laxenburg, Austria
4098 Job control and directory stack features
4099 Ken Greer, HP Labs, 1981
4100 File name completion
4101 Mike Ellis, Fairchild, 1983
4102 Command name recognition/completion
4103 Paul Placeway, Ohio State CIS Dept., 1983-1993
4104 Command line editor, prompt routines, new glob syntax and numerous
4105 fixes and speedups
4106 Karl Kleinpaste, CCI 1983-4
4107 Special aliases, directory stack extraction stuff, login/logout
4108 watch, scheduled events, and the idea of the new prompt format
4109 Rayan Zachariassen, University of Toronto, 1984
4110 ls-F and which builtins and numerous bug fixes, modifications and
4111 speedups
4112 Chris Kingsley, Caltech
4113 Fast storage allocator routines
4114 Chris Grevstad, TRW, 1987
4115 Incorporated 4.3BSD csh into tcsh
4116 Christos S. Zoulas, Cornell U. EE Dept., 1987-94
4117 Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
4118 SHORT_STRINGS support and a new version of sh.glob.c
4119 James J Dempsey, BBN, and Paul Placeway, OSU, 1988
4120 A/UX port
4121 Daniel Long, NNSC, 1988
4122 wordchars
4123 Patrick Wolfe, Kuck and Associates, Inc., 1988
4124 vi mode cleanup
4125 David C Lawrence, Rensselaer Polytechnic Institute, 1989
4126 autolist and ambiguous completion listing
4127 Alec Wolman, DEC, 1989
4128 Newlines in the prompt
4129 Matt Landau, BBN, 1989
4130 ~/.tcshrc
4131 Ray Moody, Purdue Physics, 1989
4132 Magic space bar history expansion
4133 Mordechai ????, Intel, 1989
4134 printprompt() fixes and additions
4135 Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
4136 Automatic spelling correction and prompt3
4137 Per Hedeland, Ellemtel, Sweden, 1990-
4138 Various bugfixes, improvements and manual updates
4139 Hans J. Albertsson (Sun Sweden)
4140 ampm, settc and telltc
4141 Michael Bloom
4142 Interrupt handling fixes
4143 Michael Fine, Digital Equipment Corp
4144 Extended key support
4145 Eric Schnoebelen, Convex, 1990
4146 Convex support, lots of csh bug fixes, save and restore of directory
4147 stack
4148 Ron Flax, Apple, 1990
4149 A/UX 2.0 (re)port
4150 Dan Oscarsson, LTH Sweden, 1990
4151 NLS support and simulated NLS support for non NLS sites, fixes
4152 Johan Widen, SICS Sweden, 1990
4153 shlvl, Mach support, correct-line, 8-bit printing
4154 Matt Day, Sanyo Icon, 1990
4155 POSIX termio support, SysV limit fixes
4156 Jaap Vermeulen, Sequent, 1990-91
4157 Vi mode fixes, expand-line, window change fixes, Symmetry port
4158 Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
4159 autolist beeping options, modified the history search to search for
4160 the whole string from the beginning of the line to the cursor.
4161 Scott Krotz, Motorola, 1991
4162 Minix port
4163 David Dawes, Sydney U. Australia, Physics Dept., 1991
4164 SVR4 job control fixes
4165 Jose Sousa, Interactive Systems Corp., 1991
4166 Extended vi fixes and vi delete command
4167 Marc Horowitz, MIT, 1991
4168 ANSIfication fixes, new exec hashing code, imake fixes, where
4169 Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
4170 ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
4171 and various other portability changes and bug fixes
4172 Jeff Fink, 1992
4173 complete-word-fwd and complete-word-back
4174 Harry C. Pulley, 1992
4175 Coherent port
4176 Andy Phillips, Mullard Space Science Lab U.K., 1992
4177 VMS-POSIX port
4178 Beto Appleton, IBM Corp., 1992
4179 Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
4180 SIGHUP
4181 Scott Bolte, Cray Computer Corp., 1992
4182 CSOS port
4183 Kaveh R. Ghazi, Rutgers University, 1992
4184 Tek, m88k, Titan and Masscomp ports and fixes. Added autoconf sup‐
4185 port.
4186 Mark Linderman, Cornell University, 1992
4187 OS/2 port
4188 Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
4189 Linux port
4190 Tim P. Starrin, NASA Langley Research Center Operations, 1993
4191 Read-only variables
4192 Dave Schweisguth, Yale University, 1993-4
4193 New man page and tcsh.man2html
4194 Larry Schwimmer, Stanford University, 1993
4195 AFS and HESIOD patches
4196 Luke Mewburn, RMIT University, 1994-6
4197 Enhanced directory printing in prompt, added ellipsis and rprompt.
4198 Edward Hutchins, Silicon Graphics Inc., 1996
4199 Added implicit cd.
4200 Martin Kraemer, 1997
4201 Ported to Siemens Nixdorf EBCDIC machine
4202 Amol Deshpande, Microsoft, 1997
4203 Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
4204 library and message catalog code to interface to Windows.
4205 Taga Nayuta, 1998
4206 Color ls additions.
4207
4209 Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
4210 Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
4211 the other people at Ohio State for suggestions and encouragement
4212 All the people on the net, for putting up with, reporting bugs in, and
4214 suggesting new additions to each and every version
4215 Richard M. Alderson III, for writing the `T in tcsh' section
4217Astron 6.14.00 25 March 2005 TCSH(1)