1TCSH(1) General Commands Manual TCSH(1)
2
6 tcsh - C shell with file name completion and command line editing
7
9 tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
10 tcsh -l
11
13 tcsh is an enhanced but completely compatible version of the Berkeley
14 UNIX C shell, csh(1). It is a command language interpreter usable both
15 as an interactive login shell and a shell script command processor. It
16 includes a command-line editor (see The command-line editor), program‐
17 mable word completion (see Completion and listing), spelling correction
18 (see Spelling correction), a history mechanism (see History substitu‐
19 tion), job control (see Jobs) and a C-like syntax. The NEW FEATURES
20 section describes major enhancements of tcsh over csh(1). Throughout
21 this manual, features of tcsh not found in most csh(1) implementations
22 (specifically, the 4.4BSD csh) are labeled with `(+)', and features
23 which are present in csh(1) but not usually documented are labeled with
24 `(u)'.
25 Argument list processing
27 If the first argument (argument 0) to the shell is `-' then it is a
28 login shell. A login shell can be also specified by invoking the shell
29 with the -l flag as the only argument.
30 The rest of the flag arguments are interpreted as follows:
32 -b Forces a ``break'' from option processing, causing any further
34 shell arguments to be treated as non-option arguments. The remain‐
35 ing arguments will not be interpreted as shell options. This may
36 be used to pass options to a shell script without confusion or pos‐
37 sible subterfuge. The shell will not run a set-user ID script
38 without this option.
39 -c Commands are read from the following argument (which must be
41 present, and must be a single argument), stored in the command
42 shell variable for reference, and executed. Any remaining argu‐
43 ments are placed in the argv shell variable.
44 -d The shell loads the directory stack from ~/.cshdirs as described
46 under Startup and shutdown, whether or not it is a login shell. (+)
47 -Dname[=value]
49 Sets the environment variable name to value. (Domain/OS only) (+)
50 -e The shell exits if any invoked command terminates abnormally or
52 yields a non-zero exit status.
53 -f The shell does not load any resource or startup files, or perform
55 any command hashing, and thus starts faster.
56 -F The shell uses fork(2) instead of vfork(2) to spawn processes. (+)
58 -i The shell is interactive and prompts for its top-level input, even
60 if it appears to not be a terminal. Shells are interactive without
61 this option if their inputs and outputs are terminals.
62 -l The shell is a login shell. Applicable only if -l is the only flag
64 specified.
65 -m The shell loads ~/.tcshrc even if it does not belong to the effec‐
67 tive user. Newer versions of su(1) can pass -m to the shell. (+)
68 -n The shell parses commands but does not execute them. This aids in
70 debugging shell scripts.
71 -q The shell accepts SIGQUIT (see Signal handling) and behaves when it
73 is used under a debugger. Job control is disabled. (u)
74 -s Command input is taken from the standard input.
76 -t The shell reads and executes a single line of input. A `\' may be
78 used to escape the newline at the end of this line and continue
79 onto another line.
80 -v Sets the verbose shell variable, so that command input is echoed
82 after history substitution.
83 -x Sets the echo shell variable, so that commands are echoed immedi‐
85 ately before execution.
86 -V Sets the verbose shell variable even before executing ~/.tcshrc.
88 -X Is to -x as -V is to -v.
90 --help
92 Print a help message on the standard output and exit. (+)
93 --version
95 Print the version/platform/compilation options on the standard out‐
96 put and exit. This information is also contained in the version
97 shell variable. (+)
98 After processing of flag arguments, if arguments remain but none of the
100 -c, -i, -s, or -t options were given, the first argument is taken as
101 the name of a file of commands, or ``script'', to be executed. The
102 shell opens this file and saves its name for possible resubstitution by
103 `$0'. Because many systems use either the standard version 6 or ver‐
104 sion 7 shells whose shell scripts are not compatible with this shell,
105 the shell uses such a `standard' shell to execute a script whose first
106 character is not a `#', i.e., that does not start with a comment.
107 Remaining arguments are placed in the argv shell variable.
109 Startup and shutdown
111 A login shell begins by executing commands from the system files
112 /etc/csh.cshrc and /etc/csh.login. It then executes commands from
113 files in the user's home directory: first ~/.tcshrc (+) or, if
114 ~/.tcshrc is not found, ~/.cshrc, then the contents of ~/.history (or
115 the value of the histfile shell variable) are loaded into memory, then
116 ~/.login, and finally ~/.cshdirs (or the value of the dirsfile shell
117 variable) (+). The shell may read /etc/csh.login before instead of
118 after /etc/csh.cshrc, and ~/.login before instead of after ~/.tcshrc or
119 ~/.cshrc and ~/.history, if so compiled; see the version shell vari‐
120 able. (+)
121 Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on
123 startup.
124 For examples of startup files, please consult http://tcshrc.source‐
126 forge.net.
127 Commands like stty(1) and tset(1), which need be run only once per
129 login, usually go in one's ~/.login file. Users who need to use the
130 same set of files with both csh(1) and tcsh can have only a ~/.cshrc
131 which checks for the existence of the tcsh shell variable (q.v.) before
132 using tcsh-specific commands, or can have both a ~/.cshrc and a
133 ~/.tcshrc which sources (see the builtin command) ~/.cshrc. The rest
134 of this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
135 not found, ~/.cshrc'.
136 In the normal case, the shell begins reading commands from the termi‐
138 nal, prompting with `> '. (Processing of arguments and the use of the
139 shell to process files containing command scripts are described later.)
140 The shell repeatedly reads a line of command input, breaks it into
141 words, places it on the command history list, parses it and executes
142 each command in the line.
143 One can log out by typing `^D' on an empty line, `logout' or `login' or
145 via the shell's autologout mechanism (see the autologout shell vari‐
146 able). When a login shell terminates it sets the logout shell variable
147 to `normal' or `automatic' as appropriate, then executes commands from
148 the files /etc/csh.logout and ~/.logout. The shell may drop DTR on
149 logout if so compiled; see the version shell variable.
150 The names of the system login and logout files vary from system to sys‐
152 tem for compatibility with different csh(1) variants; see FILES.
153 Editing
155 We first describe The command-line editor. The Completion and listing
156 and Spelling correction sections describe two sets of functionality
157 that are implemented as editor commands but which deserve their own
158 treatment. Finally, Editor commands lists and describes the editor
159 commands specific to the shell and their default bindings.
160 The command-line editor (+)
162 Command-line input can be edited using key sequences much like those
163 used in emacs(1) or vi(1). The editor is active only when the edit
164 shell variable is set, which it is by default in interactive shells.
165 The bindkey builtin can display and change key bindings.
166 emacs(1)-style key bindings are used by default (unless the shell was
167 compiled otherwise; see the version shell variable), but bindkey can
168 change the key bindings to vi(1)-style bindings en masse.
169 The shell always binds the arrow keys (as defined in the TERMCAP envi‐
171 ronment variable) to
172 down down-history
174 up up-history
175 left backward-char
176 right forward-char
177 unless doing so would alter another single-character binding. One can
179 set the arrow key escape sequences to the empty string with settc to
180 prevent these bindings. The ANSI/VT100 sequences for arrow keys are
181 always bound.
182 Other key bindings are, for the most part, what emacs(1) and vi(1)
184 users would expect and can easily be displayed by bindkey, so there is
185 no need to list them here. Likewise, bindkey can list the editor com‐
186 mands with a short description of each. Certain key bindings have dif‐
187 ferent behavior depending if emacs(1) or vi(1) style bindings are being
188 used; see vimode for more information.
189 Note that editor commands do not have the same notion of a ``word'' as
191 does the shell. The editor delimits words with any non-alphanumeric
192 characters not in the shell variable wordchars, while the shell recog‐
193 nizes only whitespace and some of the characters with special meanings
194 to it, listed under Lexical structure.
195 Completion and listing (+)
197 The shell is often able to complete words when given a unique abbrevia‐
198 tion. Type part of a word (for example `ls /usr/lost') and hit the tab
199 key to run the complete-word editor command. The shell completes the
200 filename `/usr/lost' to `/usr/lost+found/', replacing the incomplete
201 word with the complete word in the input buffer. (Note the terminal
202 `/'; completion adds a `/' to the end of completed directories and a
203 space to the end of other completed words, to speed typing and provide
204 a visual indicator of successful completion. The addsuffix shell vari‐
205 able can be unset to prevent this.) If no match is found (perhaps
206 `/usr/lost+found' doesn't exist), the terminal bell rings. If the word
207 is already complete (perhaps there is a `/usr/lost' on your system, or
208 perhaps you were thinking too far ahead and typed the whole thing) a
209 `/' or space is added to the end if it isn't already there.
210 Completion works anywhere in the line, not at just the end; completed
212 text pushes the rest of the line to the right. Completion in the mid‐
213 dle of a word often results in leftover characters to the right of the
214 cursor that need to be deleted.
215 Commands and variables can be completed in much the same way. For
217 example, typing `em[tab]' would complete `em' to `emacs' if emacs were
218 the only command on your system beginning with `em'. Completion can
219 find a command in any directory in path or if given a full pathname.
220 Typing `echo $ar[tab]' would complete `$ar' to `$argv' if no other
221 variable began with `ar'.
222 The shell parses the input buffer to determine whether the word you
224 want to complete should be completed as a filename, command or vari‐
225 able. The first word in the buffer and the first word following `;',
226 `|', `|&', `&&' or `||' is considered to be a command. A word begin‐
227 ning with `$' is considered to be a variable. Anything else is a file‐
228 name. An empty line is `completed' as a filename.
229 You can list the possible completions of a word at any time by typing
231 `^D' to run the delete-char-or-list-or-eof editor command. The shell
232 lists the possible completions using the ls-F builtin (q.v.) and re‐
233 prints the prompt and unfinished command line, for example:
234 > ls /usr/l[^D]
236 lbin/ lib/ local/ lost+found/
237 > ls /usr/l
238 If the autolist shell variable is set, the shell lists the remaining
240 choices (if any) whenever completion fails:
241 > set autolist
243 > nm /usr/lib/libt[tab]
244 libtermcap.a@ libtermlib.a@
245 > nm /usr/lib/libterm
246 If autolist is set to `ambiguous', choices are listed only when comple‐
248 tion fails and adds no new characters to the word being completed.
249 A filename to be completed can contain variables, your own or others'
251 home directories abbreviated with `~' (see Filename substitution) and
252 directory stack entries abbreviated with `=' (see Directory stack sub‐
253 stitution). For example,
254 > ls ~k[^D]
256 kahn kas kellogg
257 > ls ~ke[tab]
258 > ls ~kellogg/
259 or
261 > set local = /usr/local
263 > ls $lo[tab]
264 > ls $local/[^D]
265 bin/ etc/ lib/ man/ src/
266 > ls $local/
267 Note that variables can also be expanded explicitly with the expand-
269 variables editor command.
270 delete-char-or-list-or-eof lists at only the end of the line; in the
272 middle of a line it deletes the character under the cursor and on an
273 empty line it logs one out or, if ignoreeof is set, does nothing.
274 `M-^D', bound to the editor command list-choices, lists completion pos‐
275 sibilities anywhere on a line, and list-choices (or any one of the
276 related editor commands that do or don't delete, list and/or log out,
277 listed under delete-char-or-list-or-eof) can be bound to `^D' with the
278 bindkey builtin command if so desired.
279 The complete-word-fwd and complete-word-back editor commands (not bound
281 to any keys by default) can be used to cycle up and down through the
282 list of possible completions, replacing the current word with the next
283 or previous word in the list.
284 The shell variable fignore can be set to a list of suffixes to be
286 ignored by completion. Consider the following:
287 > ls
289 Makefile condiments.h~ main.o side.c
290 README main.c meal side.o
291 condiments.h main.c~
292 > set fignore = (.o \~)
293 > emacs ma[^D]
294 main.c main.c~ main.o
295 > emacs ma[tab]
296 > emacs main.c
297 `main.c~' and `main.o' are ignored by completion (but not listing),
299 because they end in suffixes in fignore. Note that a `\' was needed in
300 front of `~' to prevent it from being expanded to home as described
301 under Filename substitution. fignore is ignored if only one completion
302 is possible.
303 If the complete shell variable is set to `enhance', completion 1)
305 ignores case and 2) considers periods, hyphens and underscores (`.',
306 `-' and `_') to be word separators and hyphens and underscores to be
307 equivalent. If you had the following files
308 comp.lang.c comp.lang.perl comp.std.c++
310 comp.lang.c++ comp.std.c
311 and typed `mail -f c.l.c[tab]', it would be completed to `mail -f
313 comp.lang.c', and ^D would list `comp.lang.c' and `comp.lang.c++'.
314 `mail -f c..c++[^D]' would list `comp.lang.c++' and `comp.std.c++'.
315 Typing `rm a--file[^D]' in the following directory
316 A_silly_file a-hyphenated-file another_silly_file
318 would list all three files, because case is ignored and hyphens and
320 underscores are equivalent. Periods, however, are not equivalent to
321 hyphens or underscores.
322 If the complete shell variable is set to `Enhance', completion ignores
324 case and differences between a hyphen and an underscore word separator
325 only when the user types a lowercase character or a hyphen. Entering
326 an uppercase character or an underscore will not match the correspond‐
327 ing lowercase character or hyphen word separator. Typing `rm
328 a--file[^D]' in the directory of the previous example would still list
329 all three files, but typing `rm A--file' would match only
330 `A_silly_file' and typing `rm a__file[^D]' would match just
331 `A_silly_file' and `another_silly_file' because the user explicitly
332 used an uppercase or an underscore character.
333 Completion and listing are affected by several other shell variables:
335 recexact can be set to complete on the shortest possible unique match,
336 even if more typing might result in a longer match:
337 > ls
339 fodder foo food foonly
340 > set recexact
341 > rm fo[tab]
342 just beeps, because `fo' could expand to `fod' or `foo', but if we type
344 another `o',
345 > rm foo[tab]
347 > rm foo
348 the completion completes on `foo', even though `food' and `foonly' also
350 match. autoexpand can be set to run the expand-history editor command
351 before each completion attempt, autocorrect can be set to spelling-cor‐
352 rect the word to be completed (see Spelling correction) before each
353 completion attempt and correct can be set to complete commands automat‐
354 ically after one hits `return'. matchbeep can be set to make comple‐
355 tion beep or not beep in a variety of situations, and nobeep can be set
356 to never beep at all. nostat can be set to a list of directories
357 and/or patterns that match directories to prevent the completion mecha‐
358 nism from stat(2)ing those directories. listmax and listmaxrows can be
359 set to limit the number of items and rows (respectively) that are
360 listed without asking first. recognize_only_executables can be set to
361 make the shell list only executables when listing commands, but it is
362 quite slow.
363 Finally, the complete builtin command can be used to tell the shell how
365 to complete words other than filenames, commands and variables. Com‐
366 pletion and listing do not work on glob-patterns (see Filename substi‐
367 tution), but the list-glob and expand-glob editor commands perform
368 equivalent functions for glob-patterns.
369 Spelling correction (+)
371 The shell can sometimes correct the spelling of filenames, commands and
372 variable names as well as completing and listing them.
373 Individual words can be spelling-corrected with the spell-word editor
375 command (usually bound to M-s and M-S) and the entire input buffer with
376 spell-line (usually bound to M-$). The correct shell variable can be
377 set to `cmd' to correct the command name or `all' to correct the entire
378 line each time return is typed, and autocorrect can be set to correct
379 the word to be completed before each completion attempt.
380 When spelling correction is invoked in any of these ways and the shell
382 thinks that any part of the command line is misspelled, it prompts with
383 the corrected line:
384 > set correct = cmd
386 > lz /usr/bin
387 CORRECT>ls /usr/bin (y|n|e|a)?
388 One can answer `y' or space to execute the corrected line, `e' to leave
390 the uncorrected command in the input buffer, `a' to abort the command
391 as if `^C' had been hit, and anything else to execute the original line
392 unchanged.
393 Spelling correction recognizes user-defined completions (see the com‐
395 plete builtin command). If an input word in a position for which a
396 completion is defined resembles a word in the completion list, spelling
397 correction registers a misspelling and suggests the latter word as a
398 correction. However, if the input word does not match any of the pos‐
399 sible completions for that position, spelling correction does not reg‐
400 ister a misspelling.
401 Like completion, spelling correction works anywhere in the line, push‐
403 ing the rest of the line to the right and possibly leaving extra char‐
404 acters to the right of the cursor.
405 Editor commands (+)
407 `bindkey' lists key bindings and `bindkey -l' lists and briefly
408 describes editor commands. Only new or especially interesting editor
409 commands are described here. See emacs(1) and vi(1) for descriptions
410 of each editor's key bindings.
411 The character or characters to which each command is bound by default
413 is given in parentheses. `^character' means a control character and
414 `M-character' a meta character, typed as escape-character on terminals
415 without a meta key. Case counts, but commands that are bound to let‐
416 ters by default are bound to both lower- and uppercase letters for con‐
417 venience.
418 backward-char (^B, left)
420 Move back a character. Cursor behavior modified by vimode.
421 backward-delete-word (M-^H, M-^?)
423 Cut from beginning of current word to cursor - saved in cut
424 buffer. Word boundary behavior modified by vimode.
425 backward-word (M-b, M-B)
427 Move to beginning of current word. Word boundary and cursor
428 behavior modified by vimode.
429 beginning-of-line (^A, home)
431 Move to beginning of line. Cursor behavior modified by vimode.
432 capitalize-word (M-c, M-C)
434 Capitalize the characters from cursor to end of current word.
435 Word boundary behavior modified by vimode.
436 complete-word (tab)
438 Completes a word as described under Completion and listing.
439 complete-word-back (not bound)
441 Like complete-word-fwd, but steps up from the end of the list.
442 complete-word-fwd (not bound)
444 Replaces the current word with the first word in the list of
445 possible completions. May be repeated to step down through the
446 list. At the end of the list, beeps and reverts to the incom‐
447 plete word.
448 complete-word-raw (^X-tab)
450 Like complete-word, but ignores user-defined completions.
451 copy-prev-word (M-^_)
453 Copies the previous word in the current line into the input
454 buffer. See also insert-last-word. Word boundary behavior
455 modified by vimode.
456 dabbrev-expand (M-/)
458 Expands the current word to the most recent preceding one for
459 which the current is a leading substring, wrapping around the
460 history list (once) if necessary. Repeating dabbrev-expand
461 without any intervening typing changes to the next previous
462 word etc., skipping identical matches much like history-search-
463 backward does.
464 delete-char (not bound)
466 Deletes the character under the cursor. See also delete-char-
467 or-list-or-eof. Cursor behavior modified by vimode.
468 delete-char-or-eof (not bound)
470 Does delete-char if there is a character under the cursor or
471 end-of-file on an empty line. See also delete-char-or-list-or-
472 eof. Cursor behavior modified by vimode.
473 delete-char-or-list (not bound)
475 Does delete-char if there is a character under the cursor or
476 list-choices at the end of the line. See also delete-char-or-
477 list-or-eof.
478 delete-char-or-list-or-eof (^D)
480 Does delete-char if there is a character under the cursor,
481 list-choices at the end of the line or end-of-file on an empty
482 line. See also those three commands, each of which does only a
483 single action, and delete-char-or-eof, delete-char-or-list and
484 list-or-eof, each of which does a different two out of the
485 three.
486 delete-word (M-d, M-D)
488 Cut from cursor to end of current word - save in cut buffer.
489 Word boundary behavior modified by vimode.
490 down-history (down-arrow, ^N)
492 Like up-history, but steps down, stopping at the original input
493 line.
494 downcase-word (M-l, M-L)
496 Lowercase the characters from cursor to end of current word.
497 Word boundary behavior modified by vimode.
498 end-of-file (not bound)
500 Signals an end of file, causing the shell to exit unless the
501 ignoreeof shell variable (q.v.) is set to prevent this. See
502 also delete-char-or-list-or-eof.
503 end-of-line (^E, end)
505 Move cursor to end of line. Cursor behavior modified by
506 vimode.
507 expand-history (M-space)
509 Expands history substitutions in the current word. See History
510 substitution. See also magic-space, toggle-literal-history and
511 the autoexpand shell variable.
512 expand-glob (^X-*)
514 Expands the glob-pattern to the left of the cursor. See File‐
515 name substitution.
516 expand-line (not bound)
518 Like expand-history, but expands history substitutions in each
519 word in the input buffer.
520 expand-variables (^X-$)
522 Expands the variable to the left of the cursor. See Variable
523 substitution.
524 forward-char (^F, right)
526 Move forward one character. Cursor behavior modified by
527 vimode.
528 forward-word (M-f, M-F)
530 Move forward to end of current word. Word boundary and cursor
531 behavior modified by vimode.
532 history-search-backward (M-p, M-P)
534 Searches backwards through the history list for a command
535 beginning with the current contents of the input buffer up to
536 the cursor and copies it into the input buffer. The search
537 string may be a glob-pattern (see Filename substitution) con‐
538 taining `*', `?', `[]' or `{}'. up-history and down-history
539 will proceed from the appropriate point in the history list.
540 Emacs mode only. See also history-search-forward and i-search-
541 back.
542 history-search-forward (M-n, M-N)
544 Like history-search-backward, but searches forward.
545 i-search-back (not bound)
547 Searches backward like history-search-backward, copies the
548 first match into the input buffer with the cursor positioned at
549 the end of the pattern, and prompts with `bck: ' and the first
550 match. Additional characters may be typed to extend the
551 search, i-search-back may be typed to continue searching with
552 the same pattern, wrapping around the history list if neces‐
553 sary, (i-search-back must be bound to a single character for
554 this to work) or one of the following special characters may be
555 typed:
556 ^W Appends the rest of the word under the cursor to
558 the search pattern.
559 delete (or any character bound to backward-delete-char)
560 Undoes the effect of the last character typed and
561 deletes a character from the search pattern if
562 appropriate.
563 ^G If the previous search was successful, aborts the
564 entire search. If not, goes back to the last suc‐
565 cessful search.
566 escape Ends the search, leaving the current line in the
567 input buffer.
568 Any other character not bound to self-insert-command terminates
570 the search, leaving the current line in the input buffer, and
571 is then interpreted as normal input. In particular, a carriage
572 return causes the current line to be executed. See also i-
573 search-fwd and history-search-backward. Word boundary behavior
574 modified by vimode.
575 i-search-fwd (not bound)
577 Like i-search-back, but searches forward. Word boundary behav‐
578 ior modified by vimode.
579 insert-last-word (M-_)
581 Inserts the last word of the previous input line (`!$') into
582 the input buffer. See also copy-prev-word.
583 list-choices (M-^D)
585 Lists completion possibilities as described under Completion
586 and listing. See also delete-char-or-list-or-eof and list-
587 choices-raw.
588 list-choices-raw (^X-^D)
590 Like list-choices, but ignores user-defined completions.
591 list-glob (^X-g, ^X-G)
593 Lists (via the ls-F builtin) matches to the glob-pattern (see
594 Filename substitution) to the left of the cursor.
595 list-or-eof (not bound)
597 Does list-choices or end-of-file on an empty line. See also
598 delete-char-or-list-or-eof.
599 magic-space (not bound)
601 Expands history substitutions in the current line, like expand-
602 history, and inserts a space. magic-space is designed to be
603 bound to the space bar, but is not bound by default.
604 normalize-command (^X-?)
606 Searches for the current word in PATH and, if it is found,
607 replaces it with the full path to the executable. Special
608 characters are quoted. Aliases are expanded and quoted but
609 commands within aliases are not. This command is useful with
610 commands that take commands as arguments, e.g., `dbx' and `sh
611 -x'.
612 normalize-path (^X-n, ^X-N)
614 Expands the current word as described under the `expand' set‐
615 ting of the symlinks shell variable.
616 overwrite-mode (unbound)
618 Toggles between input and overwrite modes.
619 run-fg-editor (M-^Z)
621 Saves the current input line and looks for a stopped job where
622 the file name portion of its first word is found in the editors
623 shell variable. If editors is not set, then the file name por‐
624 tion of the EDITOR environment variable (`ed' if unset) and the
625 VISUAL environment variable (`vi' if unset) will be used. If
626 such a job is found, it is restarted as if `fg %job' had been
627 typed. This is used to toggle back and forth between an editor
628 and the shell easily. Some people bind this command to `^Z' so
629 they can do this even more easily.
630 run-help (M-h, M-H)
632 Searches for documentation on the current command, using the
633 same notion of `current command' as the completion routines,
634 and prints it. There is no way to use a pager; run-help is
635 designed for short help files. If the special alias helpcom‐
636 mand is defined, it is run with the command name as a sole
637 argument. Else, documentation should be in a file named com‐
638 mand.help, command.1, command.6, command.8 or command, which
639 should be in one of the directories listed in the HPATH envi‐
640 ronment variable. If there is more than one help file only the
641 first is printed.
642 self-insert-command (text characters)
644 In insert mode (the default), inserts the typed character into
645 the input line after the character under the cursor. In over‐
646 write mode, replaces the character under the cursor with the
647 typed character. The input mode is normally preserved between
648 lines, but the inputmode shell variable can be set to `insert'
649 or `overwrite' to put the editor in that mode at the beginning
650 of each line. See also overwrite-mode.
651 sequence-lead-in (arrow prefix, meta prefix, ^X)
653 Indicates that the following characters are part of a multi-key
654 sequence. Binding a command to a multi-key sequence really
655 creates two bindings: the first character to sequence-lead-in
656 and the whole sequence to the command. All sequences beginning
657 with a character bound to sequence-lead-in are effectively
658 bound to undefined-key unless bound to another command.
659 spell-line (M-$)
661 Attempts to correct the spelling of each word in the input buf‐
662 fer, like spell-word, but ignores words whose first character
663 is one of `-', `!', `^' or `%', or which contain `\', `*' or
664 `?', to avoid problems with switches, substitutions and the
665 like. See Spelling correction.
666 spell-word (M-s, M-S)
668 Attempts to correct the spelling of the current word as
669 described under Spelling correction. Checks each component of
670 a word which appears to be a pathname.
671 toggle-literal-history (M-r, M-R)
673 Expands or `unexpands' history substitutions in the input buf‐
674 fer. See also expand-history and the autoexpand shell vari‐
675 able.
676 undefined-key (any unbound key)
678 Beeps.
679 up-history (up-arrow, ^P)
681 Copies the previous entry in the history list into the input
682 buffer. If histlit is set, uses the literal form of the entry.
683 May be repeated to step up through the history list, stopping
684 at the top.
685 upcase-word (M-u, M-U)
687 Uppercase the characters from cursor to end of current word.
688 Word boundary behavior modified by vimode.
689 vi-beginning-of-next-word (not bound)
691 Vi goto the beginning of next word. Word boundary and cursor
692 behavior modified by vimode.
693 vi-eword (not bound)
695 Vi move to the end of the current word. Word boundary behavior
696 modified by vimode.
697 vi-search-back (?)
699 Prompts with `?' for a search string (which may be a glob-pat‐
700 tern, as with history-search-backward), searches for it and
701 copies it into the input buffer. The bell rings if no match is
702 found. Hitting return ends the search and leaves the last
703 match in the input buffer. Hitting escape ends the search and
704 executes the match. vi mode only.
705 vi-search-fwd (/)
707 Like vi-search-back, but searches forward.
708 which-command (M-?)
710 Does a which (see the description of the builtin command) on
711 the first word of the input buffer.
712 yank-pop (M-y)
714 When executed immediately after a yank or another yank-pop,
715 replaces the yanked string with the next previous string from
716 the killring. This also has the effect of rotating the kill‐
717 ring, such that this string will be considered the most
718 recently killed by a later yank command. Repeating yank-pop
719 will cycle through the killring any number of times.
720 Lexical structure
722 The shell splits input lines into words at blanks and tabs. The spe‐
723 cial characters `&', `|', `;', `<', `>', `(', and `)' and the doubled
724 characters `&&', `||', `<<' and `>>' are always separate words, whether
725 or not they are surrounded by whitespace.
726 When the shell's input is not a terminal, the character `#' is taken to
728 begin a comment. Each `#' and the rest of the input line on which it
729 appears is discarded before further parsing.
730 A special character (including a blank or tab) may be prevented from
732 having its special meaning, and possibly made part of another word, by
733 preceding it with a backslash (`\') or enclosing it in single (`''),
734 double (`"') or backward (``') quotes. When not otherwise quoted a
735 newline preceded by a `\' is equivalent to a blank, but inside quotes
736 this sequence results in a newline.
737 Furthermore, all Substitutions (see below) except History substitution
739 can be prevented by enclosing the strings (or parts of strings) in
740 which they appear with single quotes or by quoting the crucial charac‐
741 ter(s) (e.g., `$' or ``' for Variable substitution or Command substitu‐
742 tion respectively) with `\'. (Alias substitution is no exception:
743 quoting in any way any character of a word for which an alias has been
744 defined prevents substitution of the alias. The usual way of quoting
745 an alias is to precede it with a backslash.) History substitution is
746 prevented by backslashes but not by single quotes. Strings quoted with
747 double or backward quotes undergo Variable substitution and Command
748 substitution, but other substitutions are prevented.
749 Text inside single or double quotes becomes a single word (or part of
751 one). Metacharacters in these strings, including blanks and tabs, do
752 not form separate words. Only in one special case (see Command substi‐
753 tution below) can a double-quoted string yield parts of more than one
754 word; single-quoted strings never do. Backward quotes are special:
755 they signal Command substitution (q.v.), which may result in more than
756 one word.
757 Quoting complex strings, particularly strings which themselves contain
759 quoting characters, can be confusing. Remember that quotes need not be
760 used as they are in human writing! It may be easier to quote not an
761 entire string, but only those parts of the string which need quoting,
762 using different types of quoting to do so if appropriate.
763 The backslash_quote shell variable (q.v.) can be set to make back‐
765 slashes always quote `\', `'', and `"'. (+) This may make complex
766 quoting tasks easier, but it can cause syntax errors in csh(1) scripts.
767 Substitutions
769 We now describe the various transformations the shell performs on the
770 input in the order in which they occur. We note in passing the data
771 structures involved and the commands and variables which affect them.
772 Remember that substitutions can be prevented by quoting as described
773 under Lexical structure.
774 History substitution
776 Each command, or ``event'', input from the terminal is saved in the
777 history list. The previous command is always saved, and the history
778 shell variable can be set to a number to save that many commands. The
779 histdup shell variable can be set to not save duplicate events or con‐
780 secutive duplicate events.
781 Saved commands are numbered sequentially from 1 and stamped with the
783 time. It is not usually necessary to use event numbers, but the cur‐
784 rent event number can be made part of the prompt by placing an `!' in
785 the prompt shell variable.
786 By default history entries are displayed by printing each parsed token
788 separated by space; thus the redirection operator `>&!' will be dis‐
789 played as `> & !'.
790 The shell actually saves history in expanded and literal (unexpanded)
792 forms. If the histlit shell variable is set, commands that display and
793 store history use the literal form.
794 The history builtin command can print, store in a file, restore and
796 clear the history list at any time, and the savehist and histfile shell
797 variables can be set to store the history list automatically on logout
798 and restore it on login.
799 History substitutions introduce words from the history list into the
801 input stream, making it easy to repeat commands, repeat arguments of a
802 previous command in the current command, or fix spelling mistakes in
803 the previous command with little typing and a high degree of confi‐
804 dence.
805 History substitutions begin with the character `!'. They may begin
807 anywhere in the input stream, but they do not nest. The `!' may be
808 preceded by a `\' to prevent its special meaning; for convenience, a
809 `!' is passed unchanged when it is followed by a blank, tab, newline,
810 `=' or `('. History substitutions also occur when an input line begins
811 with `^'. This special abbreviation will be described later. The
812 characters used to signal history substitution (`!' and `^') can be
813 changed by setting the histchars shell variable. Any input line which
814 contains a history substitution is printed before it is executed.
815 A history substitution may have an ``event specification'', which indi‐
817 cates the event from which words are to be taken, a ``word designa‐
818 tor'', which selects particular words from the chosen event, and/or a
819 ``modifier'', which manipulates the selected words.
820 An event specification can be
822 n A number, referring to a particular event
824 -n An offset, referring to the event n before the current
825 event
826 # The current event. This should be used carefully in
827 csh(1), where there is no check for recursion. tcsh allows
828 10 levels of recursion. (+)
829 ! The previous event (equivalent to `-1')
830 s The most recent event whose first word begins with the
831 string s
832 ?s? The most recent event which contains the string s. The
833 second `?' can be omitted if it is immediately followed by
834 a newline.
835 For example, consider this bit of someone's history list:
837 9 8:30 nroff -man wumpus.man
839 10 8:31 cp wumpus.man wumpus.man.old
840 11 8:36 vi wumpus.man
841 12 8:37 diff wumpus.man.old wumpus.man
842 The commands are shown with their event numbers and time stamps. The
844 current event, which we haven't typed in yet, is event 13. `!11' and
845 `!-2' refer to event 11. `!!' refers to the previous event, 12. `!!'
846 can be abbreviated `!' if it is followed by `:' (`:' is described
847 below). `!n' refers to event 9, which begins with `n'. `!?old?' also
848 refers to event 12, which contains `old'. Without word designators or
849 modifiers history references simply expand to the entire event, so we
850 might type `!cp' to redo the copy command or `!!|more' if the `diff'
851 output scrolled off the top of the screen.
852 History references may be insulated from the surrounding text with
854 braces if necessary. For example, `!vdoc' would look for a command
855 beginning with `vdoc', and, in this example, not find one, but
856 `!{v}doc' would expand unambiguously to `vi wumpus.mandoc'. Even in
857 braces, history substitutions do not nest.
858 (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
860 `d' appended to it, tcsh expands it to the last event beginning with
861 `3d'; only completely numeric arguments are treated as event numbers.
862 This makes it possible to recall events beginning with numbers. To
863 expand `!3d' as in csh(1) say `!{3}d'.
864 To select words from an event we can follow the event specification by
866 a `:' and a designator for the desired words. The words of an input
867 line are numbered from 0, the first (usually command) word being 0, the
868 second word (first argument) being 1, etc. The basic word designators
869 are:
870 0 The first (command) word
872 n The nth argument
873 ^ The first argument, equivalent to `1'
874 $ The last argument
875 % The word matched by an ?s? search
876 x-y A range of words
877 -y Equivalent to `0-y'
878 * Equivalent to `^-$', but returns nothing if the event con‐
879 tains only 1 word
880 x* Equivalent to `x-$'
881 x- Equivalent to `x*', but omitting the last word (`$')
882 Selected words are inserted into the command line separated by single
884 blanks. For example, the `diff' command in the previous example might
885 have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
886 argument from the previous event) or `diff !-2:2 !-2:1' to select and
887 swap the arguments from the `cp' command. If we didn't care about the
888 order of the `diff' we might have said `diff !-2:1-2' or simply `diff
889 !-2:*'. The `cp' command might have been written `cp wumpus.man
890 !#:1.old', using `#' to refer to the current event. `!n:- hurkle.man'
891 would reuse the first two words from the `nroff' command to say `nroff
892 -man hurkle.man'.
893 The `:' separating the event specification from the word designator can
895 be omitted if the argument selector begins with a `^', `$', `*', `%' or
896 `-'. For example, our `diff' command might have been `diff !!^.old
897 !!^' or, equivalently, `diff !!$.old !!$'. However, if `!!' is abbre‐
898 viated `!', an argument selector beginning with `-' will be interpreted
899 as an event specification.
900 A history reference may have a word designator but no event specifica‐
902 tion. It then references the previous command. Continuing our `diff'
903 example, we could have said simply `diff !^.old !^' or, to get the
904 arguments in the opposite order, just `diff !*'.
905 The word or words in a history reference can be edited, or ``modi‐
907 fied'', by following it with one or more modifiers, each preceded by a
908 `:':
909 h Remove a trailing pathname component, leaving the head.
911 t Remove all leading pathname components, leaving the tail.
912 r Remove a filename extension `.xxx', leaving the root name.
913 e Remove all but the extension.
914 u Uppercase the first lowercase letter.
915 l Lowercase the first uppercase letter.
916 s/l/r/ Substitute l for r. l is simply a string like r, not a
917 regular expression as in the eponymous ed(1) command. Any
918 character may be used as the delimiter in place of `/'; a
919 `\' can be used to quote the delimiter inside l and r. The
920 character `&' in the r is replaced by l; `\' also quotes
921 `&'. If l is empty (``''), the l from a previous substitu‐
922 tion or the s from a previous search or event number in
923 event specification is used. The trailing delimiter may be
924 omitted if it is immediately followed by a newline.
925 & Repeat the previous substitution.
926 g Apply the following modifier once to each word.
927 a (+) Apply the following modifier as many times as possible to a
928 single word. `a' and `g' can be used together to apply a
929 modifier globally. With the `s' modifier, only the pat‐
930 terns contained in the original word are substituted, not
931 patterns that contain any substitution result.
932 p Print the new command line but do not execute it.
933 q Quote the substituted words, preventing further substitu‐
934 tions.
935 Q Same as q but in addition preserve empty variables as a
936 string containing a NUL. This is useful to preserve posi‐
937 tional arguments for example:
938 > set args=('arg 1' '' 'arg 3')
939 > tcsh -f -c 'echo ${#argv}' $args:gQ
940 3
941 x Like q, but break into words at blanks, tabs and newlines.
942 Modifiers are applied to only the first modifiable word (unless `g' is
944 used). It is an error for no word to be modifiable.
945 For example, the `diff' command might have been written as `diff wum‐
947 pus.man.old !#^:r', using `:r' to remove `.old' from the first argument
948 on the same line (`!#^'). We could say `echo hello out there', then
949 `echo !*:u' to capitalize `hello', `echo !*:au' to say it out loud, or
950 `echo !*:agu' to really shout. We might follow `mail -s "I forgot my
951 password" rot' with `!:s/rot/root' to correct the spelling of `root'
952 (but see Spelling correction for a different approach).
953 There is a special abbreviation for substitutions. `^', when it is the
955 first character on an input line, is equivalent to `!:s^'. Thus we
956 might have said `^rot^root' to make the spelling correction in the pre‐
957 vious example. This is the only history substitution which does not
958 explicitly begin with `!'.
959 (+) In csh as such, only one modifier may be applied to each history or
961 variable expansion. In tcsh, more than one may be used, for example
962 % mv wumpus.man /usr/man/man1/wumpus.1
964 % man !$:t:r
965 man wumpus
966 In csh, the result would be `wumpus.1:r'. A substitution followed by a
968 colon may need to be insulated from it with braces:
969 > mv a.out /usr/games/wumpus
971 > setenv PATH !$:h:$PATH
972 Bad ! modifier: $.
973 > setenv PATH !{-2$:h}:$PATH
974 setenv PATH /usr/games:/bin:/usr/bin:.
975 The first attempt would succeed in csh but fails in tcsh, because tcsh
977 expects another modifier after the second colon rather than `$'.
978 Finally, history can be accessed through the editor as well as through
980 the substitutions just described. The up- and down-history, history-
981 search-backward and -forward, i-search-back and -fwd, vi-search-back
982 and -fwd, copy-prev-word and insert-last-word editor commands search
983 for events in the history list and copy them into the input buffer.
984 The toggle-literal-history editor command switches between the expanded
985 and literal forms of history lines in the input buffer. expand-history
986 and expand-line expand history substitutions in the current word and in
987 the entire input buffer respectively.
988 Alias substitution
990 The shell maintains a list of aliases which can be set, unset and
991 printed by the alias and unalias commands. After a command line is
992 parsed into simple commands (see Commands) the first word of each com‐
993 mand, left-to-right, is checked to see if it has an alias. If so, the
994 first word is replaced by the alias. If the alias contains a history
995 reference, it undergoes History substitution (q.v.) as though the orig‐
996 inal command were the previous input line. If the alias does not con‐
997 tain a history reference, the argument list is left untouched.
998 Thus if the alias for `ls' were `ls -l' the command `ls /usr' would
1000 become `ls -l /usr', the argument list here being undisturbed. If the
1001 alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
1002 become `grep bill /etc/passwd'. Aliases can be used to introduce
1003 parser metasyntax. For example, `alias print 'pr \!* | lpr'' defines a
1004 ``command'' (`print') which pr(1)s its arguments to the line printer.
1005 Alias substitution is repeated until the first word of the command has
1007 no alias. If an alias substitution does not change the first word (as
1008 in the previous example) it is flagged to prevent a loop. Other loops
1009 are detected and cause an error.
1010 Some aliases are referred to by the shell; see Special aliases.
1012 Variable substitution
1014 The shell maintains a list of variables, each of which has as value a
1015 list of zero or more words. The values of shell variables can be dis‐
1016 played and changed with the set and unset commands. The system main‐
1017 tains its own list of ``environment'' variables. These can be dis‐
1018 played and changed with printenv, setenv and unsetenv.
1019 (+) Variables may be made read-only with `set -r' (q.v.). Read-only
1021 variables may not be modified or unset; attempting to do so will cause
1022 an error. Once made read-only, a variable cannot be made writable, so
1023 `set -r' should be used with caution. Environment variables cannot be
1024 made read-only.
1025 Some variables are set by the shell or referred to by it. For
1027 instance, the argv variable is an image of the shell's argument list,
1028 and words of this variable's value are referred to in special ways.
1029 Some of the variables referred to by the shell are toggles; the shell
1030 does not care what their value is, only whether they are set or not.
1031 For instance, the verbose variable is a toggle which causes command
1032 input to be echoed. The -v command line option sets this variable.
1033 Special shell variables lists all variables which are referred to by
1034 the shell.
1035 Other operations treat variables numerically. The `@' command permits
1037 numeric calculations to be performed and the result assigned to a vari‐
1038 able. Variable values are, however, always represented as (zero or
1039 more) strings. For the purposes of numeric operations, the null string
1040 is considered to be zero, and the second and subsequent words of multi-
1041 word values are ignored.
1042 After the input line is aliased and parsed, and before each command is
1044 executed, variable substitution is performed keyed by `$' characters.
1045 This expansion can be prevented by preceding the `$' with a `\' except
1046 within `"'s where it always occurs, and within `''s where it never
1047 occurs. Strings quoted by ``' are interpreted later (see Command sub‐
1048 stitution below) so `$' substitution does not occur there until later,
1049 if at all. A `$' is passed unchanged if followed by a blank, tab, or
1050 end-of-line.
1051 Input/output redirections are recognized before variable expansion, and
1053 are variable expanded separately. Otherwise, the command name and
1054 entire argument list are expanded together. It is thus possible for
1055 the first (command) word (to this point) to generate more than one
1056 word, the first of which becomes the command name, and the rest of
1057 which become arguments.
1058 Unless enclosed in `"' or given the `:q' modifier the results of vari‐
1060 able substitution may eventually be command and filename substituted.
1061 Within `"', a variable whose value consists of multiple words expands
1062 to a (portion of a) single word, with the words of the variable's value
1063 separated by blanks. When the `:q' modifier is applied to a substitu‐
1064 tion the variable will expand to multiple words with each word sepa‐
1065 rated by a blank and quoted to prevent later command or filename sub‐
1066 stitution.
1067 The following metasequences are provided for introducing variable val‐
1069 ues into the shell input. Except as noted, it is an error to reference
1070 a variable which is not set.
1071 $name
1073 ${name} Substitutes the words of the value of variable name, each sepa‐
1074 rated by a blank. Braces insulate name from following charac‐
1075 ters which would otherwise be part of it. Shell variables have
1076 names consisting of letters and digits starting with a letter.
1077 The underscore character is considered a letter. If name is
1078 not a shell variable, but is set in the environment, then that
1079 value is returned (but some of the other forms given below are
1080 not available in this case).
1081 $name[selector]
1082 ${name[selector]}
1083 Substitutes only the selected words from the value of name.
1084 The selector is subjected to `$' substitution and may consist
1085 of a single number or two numbers separated by a `-'. The
1086 first word of a variable's value is numbered `1'. If the first
1087 number of a range is omitted it defaults to `1'. If the last
1088 member of a range is omitted it defaults to `$#name'. The
1089 selector `*' selects all words. It is not an error for a range
1090 to be empty if the second argument is omitted or in range.
1091 $0 Substitutes the name of the file from which command input is
1092 being read. An error occurs if the name is not known.
1093 $number
1094 ${number}
1095 Equivalent to `$argv[number]'.
1096 $* Equivalent to `$argv', which is equivalent to `$argv[*]'.
1097 The `:' modifiers described under History substitution, except for
1099 `:p', can be applied to the substitutions above. More than one may be
1100 used. (+) Braces may be needed to insulate a variable substitution
1101 from a literal colon just as with History substitution (q.v.); any mod‐
1102 ifiers must appear within the braces.
1103 The following substitutions can not be modified with `:' modifiers.
1105 $?name
1107 ${?name}
1108 Substitutes the string `1' if name is set, `0' if it is not.
1109 $?0 Substitutes `1' if the current input filename is known, `0' if
1110 it is not. Always `0' in interactive shells.
1111 $#name
1112 ${#name}
1113 Substitutes the number of words in name.
1114 $# Equivalent to `$#argv'. (+)
1115 $%name
1116 ${%name}
1117 Substitutes the number of characters in name. (+)
1118 $%number
1119 ${%number}
1120 Substitutes the number of characters in $argv[number]. (+)
1121 $? Equivalent to `$status'. (+)
1122 $$ Substitutes the (decimal) process number of the (parent) shell.
1123 $! Substitutes the (decimal) process number of the last background
1124 process started by this shell. (+)
1125 $_ Substitutes the command line of the last command executed. (+)
1126 $< Substitutes a line from the standard input, with no further
1127 interpretation thereafter. It can be used to read from the
1128 keyboard in a shell script. (+) While csh always quotes $<, as
1129 if it were equivalent to `$<:q', tcsh does not. Furthermore,
1130 when tcsh is waiting for a line to be typed the user may type
1131 an interrupt to interrupt the sequence into which the line is
1132 to be substituted, but csh does not allow this.
1133 The editor command expand-variables, normally bound to `^X-$', can be
1135 used to interactively expand individual variables.
1136 Command, filename and directory stack substitution
1138 The remaining substitutions are applied selectively to the arguments of
1139 builtin commands. This means that portions of expressions which are
1140 not evaluated are not subjected to these expansions. For commands
1141 which are not internal to the shell, the command name is substituted
1142 separately from the argument list. This occurs very late, after input-
1143 output redirection is performed, and in a child of the main shell.
1144 Command substitution
1146 Command substitution is indicated by a command enclosed in ``'. The
1147 output from such a command is broken into separate words at blanks,
1148 tabs and newlines, and null words are discarded. The output is vari‐
1149 able and command substituted and put in place of the original string.
1150 Command substitutions inside double quotes (`"') retain blanks and
1152 tabs; only newlines force new words. The single final newline does not
1153 force a new word in any case. It is thus possible for a command sub‐
1154 stitution to yield only part of a word, even if the command outputs a
1155 complete line.
1156 By default, the shell since version 6.12 replaces all newline and car‐
1158 riage return characters in the command by spaces. If this is switched
1159 off by unsetting csubstnonl, newlines separate commands as usual.
1160 Filename substitution
1162 If a word contains any of the characters `*', `?', `[' or `{' or begins
1163 with the character `~' it is a candidate for filename substitution,
1164 also known as ``globbing''. This word is then regarded as a pattern
1165 (``glob-pattern''), and replaced with an alphabetically sorted list of
1166 file names which match the pattern.
1167 In matching filenames, the character `.' at the beginning of a filename
1169 or immediately following a `/', as well as the character `/' must be
1170 matched explicitly (unless either globdot or globstar or both are
1171 set(+)). The character `*' matches any string of characters, including
1172 the null string. The character `?' matches any single character. The
1173 sequence `[...]' matches any one of the characters enclosed. Within
1174 `[...]', a pair of characters separated by `-' matches any character
1175 lexically between the two.
1176 (+) Some glob-patterns can be negated: The sequence `[^...]' matches
1178 any single character not specified by the characters and/or ranges of
1179 characters in the braces.
1180 An entire glob-pattern can also be negated with `^':
1182 > echo *
1184 bang crash crunch ouch
1185 > echo ^cr*
1186 bang ouch
1187 Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or
1189 `~' (below) are not negated correctly.
1190 The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'. Left-
1192 to-right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
1193 `/usr/source/s1/oldls.c /usr/source/s1/ls.c'. The results of matches
1194 are sorted separately at a low level to preserve this order:
1195 `../{memo,*box}' might expand to `../memo ../box ../mbox'. (Note that
1196 `memo' was not sorted with the results of matching `*box'.) It is not
1197 an error when this construct expands to files which do not exist, but
1198 it is possible to get an error from a command to which the expanded
1199 list is passed. This construct may be nested. As a special case the
1200 words `{', `}' and `{}' are passed undisturbed.
1201 The character `~' at the beginning of a filename refers to home direc‐
1203 tories. Standing alone, i.e., `~', it expands to the invoker's home
1204 directory as reflected in the value of the home shell variable. When
1205 followed by a name consisting of letters, digits and `-' characters the
1206 shell searches for a user with that name and substitutes their home
1207 directory; thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
1208 `/usr/ken/chmach'. If the character `~' is followed by a character
1209 other than a letter or `/' or appears elsewhere than at the beginning
1210 of a word, it is left undisturbed. A command like `setenv MANPATH
1211 /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home direc‐
1212 tory substitution as one might hope.
1213 It is an error for a glob-pattern containing `*', `?', `[' or `~', with
1215 or without `^', not to match any files. However, only one pattern in a
1216 list of glob-patterns must match a file (so that, e.g., `rm *.a *.c
1217 *.o' would fail only if there were no files in the current directory
1218 ending in `.a', `.c', or `.o'), and if the nonomatch shell variable is
1219 set a pattern (or list of patterns) which matches nothing is left
1220 unchanged rather than causing an error.
1221 The globstar shell variable can be set to allow `**' or `***' as a file
1223 glob pattern that matches any string of characters including `/',
1224 recursively traversing any existing sub-directories. For example, `ls
1225 **.c' will list all the .c files in the current directory tree. If
1226 used by itself, it will match zero or more sub-directories (e.g. `ls
1227 /usr/include/**/time.h' will list any file named `time.h' in the
1228 /usr/include directory tree; `ls /usr/include/**time.h' will match any
1229 file in the /usr/include directory tree ending in `time.h'; and `ls
1230 /usr/include/**time**.h' will match any .h file with `time' either in a
1231 subdirectory name or in the filename itself). To prevent problems with
1232 recursion, the `**' glob-pattern will not descend into a symbolic link
1233 containing a directory. To override this, use `***' (+)
1234 The noglob shell variable can be set to prevent filename substitution,
1236 and the expand-glob editor command, normally bound to `^X-*', can be
1237 used to interactively expand individual filename substitutions.
1238 Directory stack substitution (+)
1240 The directory stack is a list of directories, numbered from zero, used
1241 by the pushd, popd and dirs builtin commands (q.v.). dirs can print,
1242 store in a file, restore and clear the directory stack at any time, and
1243 the savedirs and dirsfile shell variables can be set to store the
1244 directory stack automatically on logout and restore it on login. The
1245 dirstack shell variable can be examined to see the directory stack and
1246 set to put arbitrary directories into the directory stack.
1247 The character `=' followed by one or more digits expands to an entry in
1249 the directory stack. The special case `=-' expands to the last direc‐
1250 tory in the stack. For example,
1251 > dirs -v
1253 0 /usr/bin
1254 1 /usr/spool/uucp
1255 2 /usr/accts/sys
1256 > echo =1
1257 /usr/spool/uucp
1258 > echo =0/calendar
1259 /usr/bin/calendar
1260 > echo =-
1261 /usr/accts/sys
1262 The noglob and nonomatch shell variables and the expand-glob editor
1264 command apply to directory stack as well as filename substitutions.
1265 Other substitutions (+)
1267 There are several more transformations involving filenames, not
1268 strictly related to the above but mentioned here for completeness. Any
1269 filename may be expanded to a full path when the symlinks variable
1270 (q.v.) is set to `expand'. Quoting prevents this expansion, and the
1271 normalize-path editor command does it on demand. The normalize-command
1272 editor command expands commands in PATH into full paths on demand.
1273 Finally, cd and pushd interpret `-' as the old working directory
1274 (equivalent to the shell variable owd). This is not a substitution at
1275 all, but an abbreviation recognized by only those commands. Nonethe‐
1276 less, it too can be prevented by quoting.
1277 Commands
1279 The next three sections describe how the shell executes commands and
1280 deals with their input and output.
1281 Simple commands, pipelines and sequences
1283 A simple command is a sequence of words, the first of which specifies
1284 the command to be executed. A series of simple commands joined by `|'
1285 characters forms a pipeline. The output of each command in a pipeline
1286 is connected to the input of the next.
1287 Simple commands and pipelines may be joined into sequences with `;',
1289 and will be executed sequentially. Commands and pipelines can also be
1290 joined into sequences with `||' or `&&', indicating, as in the C lan‐
1291 guage, that the second is to be executed only if the first fails or
1292 succeeds respectively.
1293 A simple command, pipeline or sequence may be placed in parentheses,
1295 `()', to form a simple command, which may in turn be a component of a
1296 pipeline or sequence. A command, pipeline or sequence can be executed
1297 without waiting for it to terminate by following it with an `&'.
1298 Builtin and non-builtin command execution
1300 Builtin commands are executed within the shell. If any component of a
1301 pipeline except the last is a builtin command, the pipeline is executed
1302 in a subshell.
1303 Parenthesized commands are always executed in a subshell.
1305 (cd; pwd); pwd
1307 thus prints the home directory, leaving you where you were (printing
1309 this after the home directory), while
1310 cd; pwd
1312 leaves you in the home directory. Parenthesized commands are most
1314 often used to prevent cd from affecting the current shell.
1315 When a command to be executed is found not to be a builtin command the
1317 shell attempts to execute the command via execve(2). Each word in the
1318 variable path names a directory in which the shell will look for the
1319 command. If the shell is not given a -f option, the shell hashes the
1320 names in these directories into an internal table so that it will try
1321 an execve(2) in only a directory where there is a possibility that the
1322 command resides there. This greatly speeds command location when a
1323 large number of directories are present in the search path. This hash‐
1324 ing mechanism is not used:
1325 1. If hashing is turned explicitly off via unhash.
1327 2. If the shell was given a -f argument.
1329 3. For each directory component of path which does not begin with a
1331 `/'.
1332 4. If the command contains a `/'.
1334 In the above four cases the shell concatenates each component of the
1336 path vector with the given command name to form a path name of a file
1337 which it then attempts to execute it. If execution is successful, the
1338 search stops.
1339 If the file has execute permissions but is not an executable to the
1341 system (i.e., it is neither an executable binary nor a script that
1342 specifies its interpreter), then it is assumed to be a file containing
1343 shell commands and a new shell is spawned to read it. The shell spe‐
1344 cial alias may be set to specify an interpreter other than the shell
1345 itself.
1346 On systems which do not understand the `#!' script interpreter conven‐
1348 tion the shell may be compiled to emulate it; see the version shell
1349 variable. If so, the shell checks the first line of the file to see if
1350 it is of the form `#!interpreter arg ...'. If it is, the shell starts
1351 interpreter with the given args and feeds the file to it on standard
1352 input.
1353 Input/output
1355 The standard input and standard output of a command may be redirected
1356 with the following syntax:
1357 < name Open file name (which is first variable, command and filename
1359 expanded) as the standard input.
1360 << word Read the shell input up to a line which is identical to word.
1361 word is not subjected to variable, filename or command substi‐
1362 tution, and each input line is compared to word before any sub‐
1363 stitutions are done on this input line. Unless a quoting `\',
1364 `"', `' or ``' appears in word variable and command substitu‐
1365 tion is performed on the intervening lines, allowing `\' to
1366 quote `$', `\' and ``'. Commands which are substituted have
1367 all blanks, tabs, and newlines preserved, except for the final
1368 newline which is dropped. The resultant text is placed in an
1369 anonymous temporary file which is given to the command as stan‐
1370 dard input.
1371 > name
1372 >! name
1373 >& name
1374 >&! name
1375 The file name is used as standard output. If the file does not
1376 exist then it is created; if the file exists, it is truncated,
1377 its previous contents being lost.
1378 If the shell variable noclobber is set, then the file must not
1380 exist or be a character special file (e.g., a terminal or
1381 `/dev/null') or an error results. This helps prevent acciden‐
1382 tal destruction of files. In this case the `!' forms can be
1383 used to suppress this check. If notempty is given in noclob‐
1384 ber, `>' is allowed on empty files; if ask is set, an
1385 interacive confirmation is presented, rather than an error.
1386 The forms involving `&' route the diagnostic output into the
1388 specified file as well as the standard output. name is
1389 expanded in the same way as `<' input filenames are.
1390 >> name
1391 >>& name
1392 >>! name
1393 >>&! name
1394 Like `>', but appends output to the end of name. If the shell
1395 variable noclobber is set, then it is an error for the file not
1396 to exist, unless one of the `!' forms is given.
1397 A command receives the environment in which the shell was invoked as
1399 modified by the input-output parameters and the presence of the command
1400 in a pipeline. Thus, unlike some previous shells, commands run from a
1401 file of shell commands have no access to the text of the commands by
1402 default; rather they receive the original standard input of the shell.
1403 The `<<' mechanism should be used to present inline data. This permits
1404 shell command scripts to function as components of pipelines and allows
1405 the shell to block read its input. Note that the default standard
1406 input for a command run detached is not the empty file /dev/null, but
1407 the original standard input of the shell. If this is a terminal and if
1408 the process attempts to read from the terminal, then the process will
1409 block and the user will be notified (see Jobs).
1410 Diagnostic output may be directed through a pipe with the standard out‐
1412 put. Simply use the form `|&' rather than just `|'.
1413 The shell cannot presently redirect diagnostic output without also
1415 redirecting standard output, but `(command > output-file) >& error-
1416 file' is often an acceptable workaround. Either output-file or error-
1417 file may be `/dev/tty' to send output to the terminal.
1418 Features
1420 Having described how the shell accepts, parses and executes command
1421 lines, we now turn to a variety of its useful features.
1422 Control flow
1424 The shell contains a number of commands which can be used to regulate
1425 the flow of control in command files (shell scripts) and (in limited
1426 but useful ways) from terminal input. These commands all operate by
1427 forcing the shell to reread or skip in its input and, due to the imple‐
1428 mentation, restrict the placement of some of the commands.
1429 The foreach, switch, and while statements, as well as the if-then-else
1431 form of the if statement, require that the major keywords appear in a
1432 single simple command on an input line as shown below.
1433 If the shell's input is not seekable, the shell buffers up input when‐
1435 ever a loop is being read and performs seeks in this internal buffer to
1436 accomplish the rereading implied by the loop. (To the extent that this
1437 allows, backward gotos will succeed on non-seekable inputs.)
1438 Expressions
1440 The if, while and exit builtin commands use expressions with a common
1441 syntax. The expressions can include any of the operators described in
1442 the next three sections. Note that the @ builtin command (q.v.) has
1443 its own separate syntax.
1444 Logical, arithmetical and comparison operators
1446 These operators are similar to those of C and have the same precedence.
1447 They include
1448 || && | ^ & == != =~ !~ <= >=
1450 < > << >> + - * / % ! ~ ( )
1451 Here the precedence increases to the right, `==' `!=' `=~' and `!~',
1453 `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%'
1454 being, in groups, at the same level. The `==' `!=' `=~' and `!~' oper‐
1455 ators compare their arguments as strings; all others operate on num‐
1456 bers. The operators `=~' and `!~' are like `!=' and `==' except that
1457 the right hand side is a glob-pattern (see Filename substitution)
1458 against which the left hand operand is matched. This reduces the need
1459 for use of the switch builtin command in shell scripts when all that is
1460 really needed is pattern matching.
1461 Null or missing arguments are considered `0'. The results of all
1463 expressions are strings, which represent decimal numbers. It is impor‐
1464 tant to note that no two components of an expression can appear in the
1465 same word; except when adjacent to components of expressions which are
1466 syntactically significant to the parser (`&' `|' `<' `>' `(' `)') they
1467 should be surrounded by spaces.
1468 Command exit status
1470 Commands can be executed in expressions and their exit status returned
1471 by enclosing them in braces (`{}'). Remember that the braces should be
1472 separated from the words of the command by spaces. Command executions
1473 succeed, returning true, i.e., `1', if the command exits with status 0,
1474 otherwise they fail, returning false, i.e., `0'. If more detailed sta‐
1475 tus information is required then the command should be executed outside
1476 of an expression and the status shell variable examined.
1477 File inquiry operators
1479 Some of these operators perform true/false tests on files and related
1480 objects. They are of the form -op file, where op is one of
1481 r Read access
1483 w Write access
1484 x Execute access
1485 X Executable in the path or shell builtin, e.g., `-X ls' and `-X
1486 ls-F' are generally true, but `-X /bin/ls' is not (+)
1487 e Existence
1488 o Ownership
1489 z Zero size
1490 s Non-zero size (+)
1491 f Plain file
1492 d Directory
1493 l Symbolic link (+) *
1494 b Block special file (+)
1495 c Character special file (+)
1496 p Named pipe (fifo) (+) *
1497 S Socket special file (+) *
1498 u Set-user-ID bit is set (+)
1499 g Set-group-ID bit is set (+)
1500 k Sticky bit is set (+)
1501 t file (which must be a digit) is an open file descriptor for a
1502 terminal device (+)
1503 R Has been migrated (Convex only) (+)
1504 L Applies subsequent operators in a multiple-operator test to a
1505 symbolic link rather than to the file to which the link points
1506 (+) *
1507 file is command and filename expanded and then tested to see if it has
1509 the specified relationship to the real user. If file does not exist or
1510 is inaccessible or, for the operators indicated by `*', if the speci‐
1511 fied file type does not exist on the current system, then all inquiries
1512 return false, i.e., `0'.
1513 These operators may be combined for conciseness: `-xy file' is equiva‐
1515 lent to `-x file && -y file'. (+) For example, `-fx' is true (returns
1516 `1') for plain executable files, but not for directories.
1517 L may be used in a multiple-operator test to apply subsequent operators
1519 to a symbolic link rather than to the file to which the link points.
1520 For example, `-lLo' is true for links owned by the invoking user. Lr,
1521 Lw and Lx are always true for links and false for non-links. L has a
1522 different meaning when it is the last operator in a multiple-operator
1523 test; see below.
1524 It is possible but not useful, and sometimes misleading, to combine
1526 operators which expect file to be a file with operators which do not
1527 (e.g., X and t). Following L with a non-file operator can lead to par‐
1528 ticularly strange results.
1529 Other operators return other information, i.e., not just `0' or `1'.
1531 (+) They have the same format as before; op may be one of
1532 A Last file access time, as the number of seconds since the
1534 epoch
1535 A: Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
1536 1993'
1537 M Last file modification time
1538 M: Like M, but in timestamp format
1539 C Last inode modification time
1540 C: Like C, but in timestamp format
1541 D Device number
1542 I Inode number
1543 F Composite file identifier, in the form device:inode
1544 L The name of the file pointed to by a symbolic link
1545 N Number of (hard) links
1546 P Permissions, in octal, without leading zero
1547 P: Like P, with leading zero
1548 Pmode Equivalent to `-P file & mode', e.g., `-P22 file' returns
1549 `22' if file is writable by group and other, `20' if by
1550 group only, and `0' if by neither
1551 Pmode: Like Pmode, with leading zero
1552 U Numeric userid
1553 U: Username, or the numeric userid if the username is unknown
1554 G Numeric groupid
1555 G: Groupname, or the numeric groupid if the groupname is
1556 unknown
1557 Z Size, in bytes
1558 Only one of these operators may appear in a multiple-operator test, and
1560 it must be the last. Note that L has a different meaning at the end of
1561 and elsewhere in a multiple-operator test. Because `0' is a valid
1562 return value for many of these operators, they do not return `0' when
1563 they fail: most return `-1', and F returns `:'.
1564 If the shell is compiled with POSIX defined (see the version shell
1566 variable), the result of a file inquiry is based on the permission bits
1567 of the file and not on the result of the access(2) system call. For
1568 example, if one tests a file with -w whose permissions would ordinarily
1569 allow writing but which is on a file system mounted read-only, the test
1570 will succeed in a POSIX shell but fail in a non-POSIX shell.
1571 File inquiry operators can also be evaluated with the filetest builtin
1573 command (q.v.) (+).
1574 Jobs
1576 The shell associates a job with each pipeline. It keeps a table of
1577 current jobs, printed by the jobs command, and assigns them small inte‐
1578 ger numbers. When a job is started asynchronously with `&', the shell
1579 prints a line which looks like
1580 [1] 1234
1582 indicating that the job which was started asynchronously was job number
1584 1 and had one (top-level) process, whose process id was 1234.
1585 If you are running a job and wish to do something else you may hit the
1587 suspend key (usually `^Z'), which sends a STOP signal to the current
1588 job. The shell will then normally indicate that the job has been `Sus‐
1589 pended' and print another prompt. If the listjobs shell variable is
1590 set, all jobs will be listed like the jobs builtin command; if it is
1591 set to `long' the listing will be in long format, like `jobs -l'. You
1592 can then manipulate the state of the suspended job. You can put it in
1593 the ``background'' with the bg command or run some other commands and
1594 eventually bring the job back into the ``foreground'' with fg. (See
1595 also the run-fg-editor editor command.) A `^Z' takes effect immedi‐
1596 ately and is like an interrupt in that pending output and unread input
1597 are discarded when it is typed. The wait builtin command causes the
1598 shell to wait for all background jobs to complete.
1599 The `^]' key sends a delayed suspend signal, which does not generate a
1601 STOP signal until a program attempts to read(2) it, to the current job.
1602 This can usefully be typed ahead when you have prepared some commands
1603 for a job which you wish to stop after it has read them. The `^Y' key
1604 performs this function in csh(1); in tcsh, `^Y' is an editing command.
1605 (+)
1606 A job being run in the background stops if it tries to read from the
1608 terminal. Background jobs are normally allowed to produce output, but
1609 this can be disabled by giving the command `stty tostop'. If you set
1610 this tty option, then background jobs will stop when they try to pro‐
1611 duce output like they do when they try to read input.
1612 There are several ways to refer to jobs in the shell. The character
1614 `%' introduces a job name. If you wish to refer to job number 1, you
1615 can name it as `%1'. Just naming a job brings it to the foreground;
1616 thus `%1' is a synonym for `fg %1', bringing job 1 back into the fore‐
1617 ground. Similarly, saying `%1 &' resumes job 1 in the background, just
1618 like `bg %1'. A job can also be named by an unambiguous prefix of the
1619 string typed in to start it: `%ex' would normally restart a suspended
1620 ex(1) job, if there were only one suspended job whose name began with
1621 the string `ex'. It is also possible to say `%?string' to specify a
1622 job whose text contains string, if there is only one such job.
1623 The shell maintains a notion of the current and previous jobs. In out‐
1625 put pertaining to jobs, the current job is marked with a `+' and the
1626 previous job with a `-'. The abbreviations `%+', `%', and (by analogy
1627 with the syntax of the history mechanism) `%%' all refer to the current
1628 job, and `%-' refers to the previous job.
1629 The job control mechanism requires that the stty(1) option `new' be set
1631 on some systems. It is an artifact from a `new' implementation of the
1632 tty driver which allows generation of interrupt characters from the
1633 keyboard to tell jobs to stop. See stty(1) and the setty builtin com‐
1634 mand for details on setting options in the new tty driver.
1635 Status reporting
1637 The shell learns immediately whenever a process changes state. It nor‐
1638 mally informs you whenever a job becomes blocked so that no further
1639 progress is possible, but only right before it prints a prompt. This
1640 is done so that it does not otherwise disturb your work. If, however,
1641 you set the shell variable notify, the shell will notify you immedi‐
1642 ately of changes of status in background jobs. There is also a shell
1643 command notify which marks a single process so that its status changes
1644 will be immediately reported. By default notify marks the current
1645 process; simply say `notify' after starting a background job to mark
1646 it.
1647 When you try to leave the shell while jobs are stopped, you will be
1649 warned that `There are suspended jobs.' You may use the jobs command to
1650 see what they are. If you do this or immediately try to exit again,
1651 the shell will not warn you a second time, and the suspended jobs will
1652 be terminated.
1653 Automatic, periodic and timed events (+)
1655 There are various ways to run commands and take other actions automati‐
1656 cally at various times in the ``life cycle'' of the shell. They are
1657 summarized here, and described in detail under the appropriate Builtin
1658 commands, Special shell variables and Special aliases.
1659 The sched builtin command puts commands in a scheduled-event list, to
1661 be executed by the shell at a given time.
1662 The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
1664 aliases can be set, respectively, to execute commands when the shell
1665 wants to ring the bell, when the working directory changes, every tpe‐
1666 riod minutes, before each prompt, before each command gets executed,
1667 after each command gets executed, and when a job is started or is
1668 brought into the foreground.
1669 The autologout shell variable can be set to log out or lock the shell
1671 after a given number of minutes of inactivity.
1672 The mail shell variable can be set to check for new mail periodically.
1674 The printexitvalue shell variable can be set to print the exit status
1676 of commands which exit with a status other than zero.
1677 The rmstar shell variable can be set to ask the user, when `rm *' is
1679 typed, if that is really what was meant.
1680 The time shell variable can be set to execute the time builtin command
1682 after the completion of any process that takes more than a given number
1683 of CPU seconds.
1684 The watch and who shell variables can be set to report when selected
1686 users log in or out, and the log builtin command reports on those users
1687 at any time.
1688 Native Language System support (+)
1690 The shell is eight bit clean (if so compiled; see the version shell
1691 variable) and thus supports character sets needing this capability.
1692 NLS support differs depending on whether or not the shell was compiled
1693 to use the system's NLS (again, see version). In either case, 7-bit
1694 ASCII is the default character code (e.g., the classification of which
1695 characters are printable) and sorting, and changing the LANG or
1696 LC_CTYPE environment variables causes a check for possible changes in
1697 these respects.
1698 When using the system's NLS, the setlocale(3) function is called to
1700 determine appropriate character code/classification and sorting (e.g.,
1701 a 'en_CA.UTF-8' would yield "UTF-8" as a character code). This func‐
1702 tion typically examines the LANG and LC_CTYPE environment variables;
1703 refer to the system documentation for further details. When not using
1704 the system's NLS, the shell simulates it by assuming that the ISO
1705 8859-1 character set is used whenever either of the LANG and LC_CTYPE
1706 variables are set, regardless of their values. Sorting is not affected
1707 for the simulated NLS.
1708 In addition, with both real and simulated NLS, all printable characters
1710 in the range \200-\377, i.e., those that have M-char bindings, are
1711 automatically rebound to self-insert-command. The corresponding bind‐
1712 ing for the escape-char sequence, if any, is left alone. These charac‐
1713 ters are not rebound if the NOREBIND environment variable is set. This
1714 may be useful for the simulated NLS or a primitive real NLS which
1715 assumes full ISO 8859-1. Otherwise, all M-char bindings in the range
1716 \240-\377 are effectively undone. Explicitly rebinding the relevant
1717 keys with bindkey is of course still possible.
1718 Unknown characters (i.e., those that are neither printable nor control
1720 characters) are printed in the format \nnn. If the tty is not in 8 bit
1721 mode, other 8 bit characters are printed by converting them to ASCII
1722 and using standout mode. The shell never changes the 7/8 bit mode of
1723 the tty and tracks user-initiated changes of 7/8 bit mode. NLS users
1724 (or, for that matter, those who want to use a meta key) may need to
1725 explicitly set the tty in 8 bit mode through the appropriate stty(1)
1726 command in, e.g., the ~/.login file.
1727 OS variant support (+)
1729 A number of new builtin commands are provided to support features in
1730 particular operating systems. All are described in detail in the
1731 Builtin commands section.
1732 On systems that support TCF (aix-ibm370, aix-ps2), getspath and
1734 setspath get and set the system execution path, getxvers and setxvers
1735 get and set the experimental version prefix and migrate migrates pro‐
1736 cesses between sites. The jobs builtin prints the site on which each
1737 job is executing.
1738 Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
1740 operating system.
1741 Under Domain/OS, inlib adds shared libraries to the current environ‐
1743 ment, rootnode changes the rootnode and ver changes the systype.
1744 Under Mach, setpath is equivalent to Mach's setpath(1).
1746 Under Masscomp/RTU and Harris CX/UX, universe sets the universe.
1748 Under Harris CX/UX, ucb or att runs a command under the specified uni‐
1750 verse.
1751 Under Convex/OS, warp prints or sets the universe.
1753 The VENDOR, OSTYPE and MACHTYPE environment variables indicate respec‐
1755 tively the vendor, operating system and machine type (microprocessor
1756 class or machine model) of the system on which the shell thinks it is
1757 running. These are particularly useful when sharing one's home direc‐
1758 tory between several types of machines; one can, for example,
1759 set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)
1761 in one's ~/.login and put executables compiled for each machine in the
1763 appropriate directory.
1764 The version shell variable indicates what options were chosen when the
1766 shell was compiled.
1767 Note also the newgrp builtin, the afsuser and echo_style shell vari‐
1769 ables and the system-dependent locations of the shell's input files
1770 (see FILES).
1771 Signal handling
1773 Login shells ignore interrupts when reading the file ~/.logout. The
1774 shell ignores quit signals unless started with -q. Login shells catch
1775 the terminate signal, but non-login shells inherit the terminate behav‐
1776 ior from their parents. Other signals have the values which the shell
1777 inherited from its parent.
1778 In shell scripts, the shell's handling of interrupt and terminate sig‐
1780 nals can be controlled with onintr, and its handling of hangups can be
1781 controlled with hup and nohup.
1782 The shell exits on a hangup (see also the logout shell variable). By
1784 default, the shell's children do too, but the shell does not send them
1785 a hangup when it exits. hup arranges for the shell to send a hangup to
1786 a child when it exits, and nohup sets a child to ignore hangups.
1787 Terminal management (+)
1789 The shell uses three different sets of terminal (``tty'') modes:
1790 `edit', used when editing, `quote', used when quoting literal charac‐
1791 ters, and `execute', used when executing commands. The shell holds
1792 some settings in each mode constant, so commands which leave the tty in
1793 a confused state do not interfere with the shell. The shell also
1794 matches changes in the speed and padding of the tty. The list of tty
1795 modes that are kept constant can be examined and modified with the
1796 setty builtin. Note that although the editor uses CBREAK mode (or its
1797 equivalent), it takes typed-ahead characters anyway.
1798 The echotc, settc and telltc commands can be used to manipulate and
1800 debug terminal capabilities from the command line.
1801 On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win‐
1803 dow resizing automatically and adjusts the environment variables LINES
1804 and COLUMNS if set. If the environment variable TERMCAP contains li#
1805 and co# fields, the shell adjusts them to reflect the new window size.
1806
1808 The next sections of this manual describe all of the available Builtin
1809 commands, Special aliases and Special shell variables.
1810 Builtin commands
1812 %job A synonym for the fg builtin command.
1813 %job & A synonym for the bg builtin command.
1815 : Does nothing, successfully.
1817 @
1819 @ name = expr
1820 @ name[index] = expr
1821 @ name++|--
1822 @ name[index]++|--
1823 The first form prints the values of all shell variables.
1824 The second form assigns the value of expr to name. The third
1826 form assigns the value of expr to the index'th component of
1827 name; both name and its index'th component must already exist.
1828 expr may contain the operators `*', `+', etc., as in C. If
1830 expr contains `<', `>', `&' or `' then at least that part of
1831 expr must be placed within `()'. Note that the syntax of expr
1832 has nothing to do with that described under Expressions.
1833 The fourth and fifth forms increment (`++') or decrement (`--')
1835 name or its index'th component.
1836 The space between `@' and name is required. The spaces between
1838 name and `=' and between `=' and expr are optional. Components
1839 of expr must be separated by spaces.
1840 alias [name [wordlist]]
1842 Without arguments, prints all aliases. With name, prints the
1843 alias for name. With name and wordlist, assigns wordlist as
1844 the alias of name. wordlist is command and filename substi‐
1845 tuted. name may not be `alias' or `unalias'. See also the
1846 unalias builtin command.
1847 alloc Shows the amount of dynamic memory acquired, broken down into
1849 used and free memory. With an argument shows the number of
1850 free and used blocks in each size category. The categories
1851 start at size 8 and double at each step. This command's output
1852 may vary across system types, because systems other than the
1853 VAX may use a different memory allocator.
1854 bg [%job ...]
1856 Puts the specified jobs (or, without arguments, the current
1857 job) into the background, continuing each if it is stopped.
1858 job may be a number, a string, `', `%', `+' or `-' as described
1859 under Jobs.
1860 bindkey [-l|-d|-e|-v|-u] (+)
1862 bindkey [-a] [-b] [-k] [-r] [--] key (+)
1863 bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
1864 Without options, the first form lists all bound keys and the
1865 editor command to which each is bound, the second form lists
1866 the editor command to which key is bound and the third form
1867 binds the editor command command to key. Options include:
1868 -l Lists all editor commands and a short description of each.
1870 -d Binds all keys to the standard bindings for the default
1871 editor, as per -e and -v below.
1872 -e Binds all keys to emacs(1)-style bindings. Unsets vimode.
1873 -v Binds all keys to vi(1)-style bindings. Sets vimode.
1874 -a Lists or changes key-bindings in the alternative key map.
1875 This is the key map used in vimode command mode.
1876 -b key is interpreted as a control character written ^charac‐
1877 ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char‐
1878 acter written M-character (e.g., `M-A'), a function key
1879 written F-string (e.g., `F-string'), or an extended prefix
1880 key written X-character (e.g., `X-A').
1881 -k key is interpreted as a symbolic arrow key name, which may
1882 be one of `down', `up', `left' or `right'.
1883 -r Removes key's binding. Be careful: `bindkey -r' does not
1884 bind key to self-insert-command (q.v.), it unbinds key com‐
1885 pletely.
1886 -c command is interpreted as a builtin or external command
1887 instead of an editor command.
1888 -s command is taken as a literal string and treated as termi‐
1889 nal input when key is typed. Bound keys in command are
1890 themselves reinterpreted, and this continues for ten levels
1891 of interpretation.
1892 -- Forces a break from option processing, so the next word is
1893 taken as key even if it begins with '-'.
1894 -u (or any invalid option)
1895 Prints a usage message.
1896 key may be a single character or a string. If a command is
1898 bound to a string, the first character of the string is bound
1899 to sequence-lead-in and the entire string is bound to the com‐
1900 mand.
1901 Control characters in key can be literal (they can be typed by
1903 preceding them with the editor command quoted-insert, normally
1904 bound to `^V') or written caret-character style, e.g., `^A'.
1905 Delete is written `^?' (caret-question mark). key and command
1906 can contain backslashed escape sequences (in the style of Sys‐
1907 tem V echo(1)) as follows:
1908 \a Bell
1910 \b Backspace
1911 \e Escape
1912 \f Form feed
1913 \n Newline
1914 \r Carriage return
1915 \t Horizontal tab
1916 \v Vertical tab
1917 \nnn The ASCII character corresponding to the octal num‐
1918 ber nnn
1919 `\' nullifies the special meaning of the following character,
1921 if it has any, notably `\' and `^'.
1922 bs2cmd bs2000-command (+)
1924 Passes bs2000-command to the BS2000 command interpreter for
1925 execution. Only non-interactive commands can be executed, and
1926 it is not possible to execute any command that would overlay
1927 the image of the current process, like /EXECUTE or /CALL-PROCE‐
1928 DURE. (BS2000 only)
1929 break Causes execution to resume after the end of the nearest enclos‐
1931 ing foreach or while. The remaining commands on the current
1932 line are executed. Multi-level breaks are thus possible by
1933 writing them all on one line.
1934 breaksw Causes a break from a switch, resuming after the endsw.
1936 builtins (+)
1938 Prints the names of all builtin commands.
1939 bye (+) A synonym for the logout builtin command. Available only if
1941 the shell was so compiled; see the version shell variable.
1942 case label:
1944 A label in a switch statement as discussed below.
1945 cd [-p] [-l] [-n|-v] [I--] [name]
1947 If a directory name is given, changes the shell's working
1948 directory to name. If not, changes to home, unless the cdto‐
1949 home variable is not set, in which case a name is required. If
1950 name is `-' it is interpreted as the previous working directory
1951 (see Other substitutions). (+) If name is not a subdirectory
1952 of the current directory (and does not begin with `/', `./' or
1953 `../'), each component of the variable cdpath is checked to see
1954 if it has a subdirectory name. Finally, if all else fails but
1955 name is a shell variable whose value begins with `/' or '.',
1956 then this is tried to see if it is a directory, and the -p
1957 option is implied.
1958 With -p, prints the final directory stack, just like dirs. The
1960 -l, -n and -v flags have the same effect on cd as on dirs, and
1961 they imply -p. (+) Using -- forces a break from option pro‐
1962 cessing so the next word is taken as the directory name even if
1963 it begins with '-'. (+)
1964 See also the implicitcd and cdtohome shell variables.
1966 chdir A synonym for the cd builtin command.
1968 complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
1970 Without arguments, lists all completions. With command, lists
1971 completions for command. With command and word etc., defines
1972 completions.
1973 command may be a full command name or a glob-pattern (see File‐
1975 name substitution). It can begin with `-' to indicate that
1976 completion should be used only when command is ambiguous.
1977 word specifies which word relative to the current word is to be
1979 completed, and may be one of the following:
1980 c Current-word completion. pattern is a glob-pattern
1982 which must match the beginning of the current word on
1983 the command line. pattern is ignored when completing
1984 the current word.
1985 C Like c, but includes pattern when completing the cur‐
1986 rent word.
1987 n Next-word completion. pattern is a glob-pattern which
1988 must match the beginning of the previous word on the
1989 command line.
1990 N Like n, but must match the beginning of the word two
1991 before the current word.
1992 p Position-dependent completion. pattern is a numeric
1993 range, with the same syntax used to index shell vari‐
1994 ables, which must include the current word.
1995 list, the list of possible completions, may be one of the fol‐
1997 lowing:
1998 a Aliases
2000 b Bindings (editor commands)
2001 c Commands (builtin or external commands)
2002 C External commands which begin with the supplied
2003 path prefix
2004 d Directories
2005 D Directories which begin with the supplied path pre‐
2006 fix
2007 e Environment variables
2008 f Filenames
2009 F Filenames which begin with the supplied path prefix
2010 g Groupnames
2011 j Jobs
2012 l Limits
2013 n Nothing
2014 s Shell variables
2015 S Signals
2016 t Plain (``text'') files
2017 T Plain (``text'') files which begin with the sup‐
2018 plied path prefix
2019 v Any variables
2020 u Usernames
2021 x Like n, but prints select when list-choices is
2022 used.
2023 X Completions
2024 $var Words from the variable var
2025 (...) Words from the given list
2026 `...` Words from the output of command
2027 select is an optional glob-pattern. If given, words from only
2029 list that match select are considered and the fignore shell
2030 variable is ignored. The last three types of completion may
2031 not have a select pattern, and x uses select as an explanatory
2032 message when the list-choices editor command is used.
2033 suffix is a single character to be appended to a successful
2035 completion. If null, no character is appended. If omitted (in
2036 which case the fourth delimiter can also be omitted), a slash
2037 is appended to directories and a space to other words.
2038 command invoked from `...` version has additional environment
2040 variable set, the variable name is COMMAND_LINE and contains
2041 (as its name indicates) contents of the current (already typed
2042 in) command line. One can examine and use contents of the
2043 COMMAND_LINE variable in her custom script to build more
2044 sophisticated completions (see completion for svn(1) included
2045 in this package).
2046 Now for some examples. Some commands take only directories as
2048 arguments, so there's no point completing plain files.
2049 > complete cd 'p/1/d/'
2051 completes only the first word following `cd' (`p/1') with a
2053 directory. p-type completion can also be used to narrow down
2054 command completion:
2055 > co[^D]
2057 complete compress
2058 > complete -co* 'p/0/(compress)/'
2059 > co[^D]
2060 > compress
2061 This completion completes commands (words in position 0, `p/0')
2063 which begin with `co' (thus matching `co*') to `compress' (the
2064 only word in the list). The leading `-' indicates that this
2065 completion is to be used with only ambiguous commands.
2066 > complete find 'n/-user/u/'
2068 is an example of n-type completion. Any word following `find'
2070 and immediately following `-user' is completed from the list of
2071 users.
2072 > complete cc 'c/-I/d/'
2074 demonstrates c-type completion. Any word following `cc' and
2076 beginning with `-I' is completed as a directory. `-I' is not
2077 taken as part of the directory because we used lowercase c.
2078 Different lists are useful with different commands.
2080 > complete alias 'p/1/a/'
2082 > complete man 'p/*/c/'
2083 > complete set 'p/1/s/'
2084 > complete true 'p/1/x:Truth has no options./'
2085 These complete words following `alias' with aliases, `man' with
2087 commands, and `set' with shell variables. `true' doesn't have
2088 any options, so x does nothing when completion is attempted and
2089 prints `Truth has no options.' when completion choices are
2090 listed.
2091 Note that the man example, and several other examples below,
2093 could just as well have used 'c/*' or 'n/*' as 'p/*'.
2094 Words can be completed from a variable evaluated at completion
2096 time,
2097 > complete ftp 'p/1/$hostnames/'
2099 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
2100 > ftp [^D]
2101 rtfm.mit.edu tesla.ee.cornell.edu
2102 > ftp [^C]
2103 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
2104 uunet.uu.net)
2105 > ftp [^D]
2106 rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net
2107 or from a command run at completion time:
2109 > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
2111 > kill -9 [^D]
2112 23113 23377 23380 23406 23429 23529 23530 PID
2113 Note that the complete command does not itself quote its argu‐
2115 ments, so the braces, space and `$' in `{print $1}' must be
2116 quoted explicitly.
2117 One command can have multiple completions:
2119 > complete dbx 'p/2/(core)/' 'p/*/c/'
2121 completes the second argument to `dbx' with the word `core' and
2123 all other arguments with commands. Note that the positional
2124 completion is specified before the next-word completion.
2125 Because completions are evaluated from left to right, if the
2126 next-word completion were specified first it would always match
2127 and the positional completion would never be executed. This is
2128 a common mistake when defining a completion.
2129 The select pattern is useful when a command takes files with
2131 only particular forms as arguments. For example,
2132 > complete cc 'p/*/f:*.[cao]/'
2134 completes `cc' arguments to files ending in only `.c', `.a', or
2136 `.o'. select can also exclude files, using negation of a glob-
2137 pattern as described under Filename substitution. One might
2138 use
2139 > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'
2141 to exclude precious source code from `rm' completion. Of
2143 course, one could still type excluded names manually or over‐
2144 ride the completion mechanism using the complete-word-raw or
2145 list-choices-raw editor commands (q.v.).
2146 The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
2148 respectively, but they use the select argument in a different
2149 way: to restrict completion to files beginning with a particu‐
2150 lar path prefix. For example, the Elm mail program uses `=' as
2151 an abbreviation for one's mail directory. One might use
2152 > complete elm c@=@F:$HOME/Mail/@
2154 to complete `elm -f =' as if it were `elm -f ~/Mail/'. Note
2156 that we used `@' instead of `/' to avoid confusion with the
2157 select argument, and we used `$HOME' instead of `~' because
2158 home directory substitution works at only the beginning of a
2159 word.
2160 suffix is used to add a nonstandard suffix (not space or `/'
2162 for directories) to completed words.
2163 > complete finger 'c/*@/$hostnames/' 'p/1/u/@'
2165 completes arguments to `finger' from the list of users, appends
2167 an `@', and then completes after the `@' from the `hostnames'
2168 variable. Note again the order in which the completions are
2169 specified.
2170 Finally, here's a complex example for inspiration:
2172 > complete find \
2174 'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
2175 ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
2176 'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
2177 'n/-type/(b c d f l p s)/' \
2178 ´c/-/(name newer cpio ncpio exec ok user \
2179 group fstype type atime ctime depth inum \
2180 ls mtime nogroup nouser perm print prune \
2181 size xdev)/' \
2182 'p/*/d/'
2183 This completes words following `-name', `-newer', `-cpio' or
2185 `ncpio' (note the pattern which matches both) to files, words
2186 following `-exec' or `-ok' to commands, words following `user'
2187 and `group' to users and groups respectively and words follow‐
2188 ing `-fstype' or `-type' to members of the given lists. It
2189 also completes the switches themselves from the given list
2190 (note the use of c-type completion) and completes anything not
2191 otherwise completed to a directory. Whew.
2192 Remember that programmed completions are ignored if the word
2194 being completed is a tilde substitution (beginning with `~') or
2195 a variable (beginning with `$'). See also the uncomplete
2196 builtin command.
2197 continue
2199 Continues execution of the nearest enclosing while or foreach.
2200 The rest of the commands on the current line are executed.
2201 default:
2203 Labels the default case in a switch statement. It should come
2204 after all case labels.
2205 dirs [-l] [-n|-v]
2207 dirs -S|-L [filename] (+)
2208 dirs -c (+)
2209 The first form prints the directory stack. The top of the
2210 stack is at the left and the first directory in the stack is
2211 the current directory. With -l, `~' or `~name' in the output
2212 is expanded explicitly to home or the pathname of the home
2213 directory for user name. (+) With -n, entries are wrapped
2214 before they reach the edge of the screen. (+) With -v, entries
2215 are printed one per line, preceded by their stack positions.
2216 (+) If more than one of -n or -v is given, -v takes precedence.
2217 -p is accepted but does nothing.
2218 With -S, the second form saves the directory stack to filename
2220 as a series of cd and pushd commands. With -L, the shell
2221 sources filename, which is presumably a directory stack file
2222 saved by the -S option or the savedirs mechanism. In either
2223 case, dirsfile is used if filename is not given and ~/.cshdirs
2224 is used if dirsfile is unset.
2225 Note that login shells do the equivalent of `dirs -L' on
2227 startup and, if savedirs is set, `dirs -S' before exiting.
2228 Because only ~/.tcshrc is normally sourced before ~/.cshdirs,
2229 dirsfile should be set in ~/.tcshrc rather than ~/.login.
2230 The last form clears the directory stack.
2232 echo [-n] word ...
2234 Writes each word to the shell's standard output, separated by
2235 spaces and terminated with a newline. The echo_style shell
2236 variable may be set to emulate (or not) the flags and escape
2237 sequences of the BSD and/or System V versions of echo; see
2238 echo(1).
2239 echotc [-sv] arg ... (+)
2241 Exercises the terminal capabilities (see termcap(5)) in args.
2242 For example, 'echotc home' sends the cursor to the home posi‐
2243 tion, 'echotc cm 3 10' sends it to column 3 and row 10, and
2244 'echotc ts 0; echo "This is a test."; echotc fs' prints "This
2245 is a test." in the status line.
2246 If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
2248 value of that capability ("yes" or "no" indicating that the
2249 terminal does or does not have that capability). One might use
2250 this to make the output from a shell script less verbose on
2251 slow terminals, or limit command output to the number of lines
2252 on the screen:
2253 > set history=`echotc lines`
2255 > @ history--
2256 Termcap strings may contain wildcards which will not echo cor‐
2258 rectly. One should use double quotes when setting a shell
2259 variable to a terminal capability string, as in the following
2260 example that places the date in the status line:
2261 > set tosl="`echotc ts 0`"
2263 > set frsl="`echotc fs`"
2264 > echo -n "$tosl";date; echo -n "$frsl"
2265 With -s, nonexistent capabilities return the empty string
2267 rather than causing an error. With -v, messages are verbose.
2268 else
2270 end
2271 endif
2272 endsw See the description of the foreach, if, switch, and while
2273 statements below.
2274 eval arg ...
2276 Treats the arguments as input to the shell and executes the
2277 resulting command(s) in the context of the current shell. This
2278 is usually used to execute commands generated as the result of
2279 command or variable substitution, because parsing occurs before
2280 these substitutions. See tset(1) for a sample use of eval.
2281 exec command
2283 Executes the specified command in place of the current shell.
2284 exit [expr]
2286 The shell exits either with the value of the specified expr (an
2287 expression, as described under Expressions) or, without expr,
2288 with the value 0.
2289 fg [%job ...]
2291 Brings the specified jobs (or, without arguments, the current
2292 job) into the foreground, continuing each if it is stopped.
2293 job may be a number, a string, `', `%', `+' or `-' as described
2294 under Jobs. See also the run-fg-editor editor command.
2295 filetest -op file ... (+)
2297 Applies op (which is a file inquiry operator as described under
2298 File inquiry operators) to each file and returns the results as
2299 a space-separated list.
2300 foreach name (wordlist)
2302 ...
2303 end Successively sets the variable name to each member of wordlist
2304 and executes the sequence of commands between this command and
2305 the matching end. (Both foreach and end must appear alone on
2306 separate lines.) The builtin command continue may be used to
2307 continue the loop prematurely and the builtin command break to
2308 terminate it prematurely. When this command is read from the
2309 terminal, the loop is read once prompting with `foreach? ' (or
2310 prompt2) before any statements in the loop are executed. If
2311 you make a mistake typing in a loop at the terminal you can rub
2312 it out.
2313 getspath (+)
2315 Prints the system execution path. (TCF only)
2316 getxvers (+)
2318 Prints the experimental version prefix. (TCF only)
2319 glob wordlist
2321 Like echo, but the `-n' parameter is not recognized and words
2322 are delimited by null characters in the output. Useful for
2323 programs which wish to use the shell to filename expand a list
2324 of words.
2325 goto word
2327 word is filename and command-substituted to yield a string of
2328 the form `label'. The shell rewinds its input as much as pos‐
2329 sible, searches for a line of the form `label:', possibly pre‐
2330 ceded by blanks or tabs, and continues execution after that
2331 line.
2332 hashstat
2334 Prints a statistics line indicating how effective the internal
2335 hash table has been at locating commands (and avoiding exec's).
2336 An exec is attempted for each component of the path where the
2337 hash function indicates a possible hit, and in each component
2338 which does not begin with a `/'.
2339 On machines without vfork(2), prints only the number and size
2341 of hash buckets.
2342 history [-hTr] [n]
2344 history -S|-L|-M [filename] (+)
2345 history -c (+)
2346 The first form prints the history event list. If n is given
2347 only the n most recent events are printed or saved. With -h,
2348 the history list is printed without leading numbers. If -T is
2349 specified, timestamps are printed also in comment form. (This
2350 can be used to produce files suitable for loading with 'history
2351 -L' or 'source -h'.) With -r, the order of printing is most
2352 recent first rather than oldest first.
2353 With -S, the second form saves the history list to filename.
2355 If the first word of the savehist shell variable is set to a
2356 number, at most that many lines are saved. If the second word
2357 of savehist is set to `merge', the history list is merged with
2358 the existing history file instead of replacing it (if there is
2359 one) and sorted by time stamp. (+) Merging is intended for an
2360 environment like the X Window System with several shells in
2361 simultaneous use. If the second word of savehist is `merge'
2362 and the third word is set to `lock', the history file update
2363 will be serialized with other shell sessions that would possi‐
2364 bly like to merge history at exactly the same time.
2365 With -L, the shell appends filename, which is presumably a his‐
2367 tory list saved by the -S option or the savehist mechanism, to
2368 the history list. -M is like -L, but the contents of filename
2369 are merged into the history list and sorted by timestamp. In
2370 either case, histfile is used if filename is not given and
2371 ~/.history is used if histfile is unset. `history -L' is
2372 exactly like 'source -h' except that it does not require a
2373 filename.
2374 Note that login shells do the equivalent of `history -L' on
2376 startup and, if savehist is set, `history -S' before exiting.
2377 Because only ~/.tcshrc is normally sourced before ~/.history,
2378 histfile should be set in ~/.tcshrc rather than ~/.login.
2379 If histlit is set, the first and second forms print and save
2381 the literal (unexpanded) form of the history list.
2382 The last form clears the history list.
2384 hup [command] (+)
2386 With command, runs command such that it will exit on a hangup
2387 signal and arranges for the shell to send it a hangup signal
2388 when the shell exits. Note that commands may set their own
2389 response to hangups, overriding hup. Without an argument,
2390 causes the non-interactive shell only to exit on a hangup for
2391 the remainder of the script. See also Signal handling and the
2392 nohup builtin command.
2393 if (expr) command
2395 If expr (an expression, as described under Expressions) evalu‐
2396 ates true, then command is executed. Variable substitution on
2397 command happens early, at the same time it does for the rest of
2398 the if command. command must be a simple command, not an
2399 alias, a pipeline, a command list or a parenthesized command
2400 list, but it may have arguments. Input/output redirection
2401 occurs even if expr is false and command is thus not executed;
2402 this is a bug.
2403 if (expr) then
2405 ...
2406 else if (expr2) then
2407 ...
2408 else
2409 ...
2410 endif If the specified expr is true then the commands to the first
2411 else are executed; otherwise if expr2 is true then the commands
2412 to the second else are executed, etc. Any number of else-if
2413 pairs are possible; only one endif is needed. The else part is
2414 likewise optional. (The words else and endif must appear at
2415 the beginning of input lines; the if must appear alone on its
2416 input line or after an else.)
2417 inlib shared-library ... (+)
2419 Adds each shared-library to the current environment. There is
2420 no way to remove a shared library. (Domain/OS only)
2421 jobs [-l]
2423 Lists the active jobs. With -l, lists process IDs in addition
2424 to the normal information. On TCF systems, prints the site on
2425 which each job is executing.
2426 kill [-s signal] %job|pid ...
2428 kill -l The first and second forms sends the specified signal (or, if
2429 none is given, the TERM (terminate) signal) to the specified
2430 jobs or processes. job may be a number, a string, `', `%', `+'
2431 or `-' as described under Jobs. Signals are either given by
2432 number or by name (as given in /usr/include/signal.h, stripped
2433 of the prefix `SIG'). There is no default job; saying just
2434 `kill' does not send a signal to the current job. If the sig‐
2435 nal being sent is TERM (terminate) or HUP (hangup), then the
2436 job or process is sent a CONT (continue) signal as well. The
2437 third form lists the signal names.
2438 limit [-h] [resource [maximum-use]]
2440 Limits the consumption by the current process and each process
2441 it creates to not individually exceed maximum-use on the speci‐
2442 fied resource. If no maximum-use is given, then the current
2443 limit is printed; if no resource is given, then all limitations
2444 are given. If the -h flag is given, the hard limits are used
2445 instead of the current limits. The hard limits impose a ceil‐
2446 ing on the values of the current limits. Only the super-user
2447 may raise the hard limits, but a user may lower or raise the
2448 current limits within the legal range.
2449 Controllable resources currently include (if supported by the
2451 OS):
2452 cputime
2454 the maximum number of cpu-seconds to be used by each
2455 process
2456 filesize
2458 the largest single file which can be created
2459 datasize
2461 the maximum growth of the data+stack region via sbrk(2)
2462 beyond the end of the program text
2463 stacksize
2465 the maximum size of the automatically-extended stack
2466 region
2467 coredumpsize
2469 the size of the largest core dump that will be created
2470 memoryuse
2472 the maximum amount of physical memory a process may have
2473 allocated to it at a given time
2474 NOTE: Changing this value has no effect. Support has
2476 been removed from Linux kernel v2.6 and newer.
2477 vmemoryuse
2479 the maximum amount of virtual memory a process may have
2480 allocated to it at a given time (address space)
2481 vmemoryuse
2483 the maximum amount of virtual memory a process may have
2484 allocated to it at a given time
2485 heapsize
2487 the maximum amount of memory a process may allocate per
2488 brk() system call
2489 descriptors or openfiles
2491 the maximum number of open files for this process
2492 pseudoterminals
2494 the maximum number of pseudo-terminals for this user
2495 kqueues
2497 the maximum number of kqueues allocated for this process
2498 concurrency
2500 the maximum number of threads for this process
2501 memorylocked
2503 the maximum size which a process may lock into memory
2504 using mlock(2)
2505 maxproc
2507 the maximum number of simultaneous processes for this
2508 user id
2509 maxthread
2511 the maximum number of simultaneous threads (lightweight
2512 processes) for this user id
2513 threads
2515 the maximum number of threads for this process
2516 sbsize the maximum size of socket buffer usage for this user
2518 swapsize
2520 the maximum amount of swap space reserved or used for
2521 this user
2522 maxlocks
2524 the maximum number of locks for this user
2525 posixlocks
2527 the maximum number of POSIX advisory locks for this user
2528 maxsignal
2530 the maximum number of pending signals for this user
2531 maxmessage
2533 the maximum number of bytes in POSIX mqueues for this
2534 user
2535 maxnice
2537 the maximum nice priority the user is allowed to raise
2538 mapped from [19...-20] to [0...39] for this user
2539 maxrtprio
2541 the maximum realtime priority for this user maxrttime
2542 the timeout for RT tasks in microseconds for this user.
2543 maximum-use may be given as a (floating point or integer) num‐
2545 ber followed by a scale factor. For all limits other than
2546 cputime the default scale is `k' or `kilobytes' (1024 bytes); a
2547 scale factor of `m' or `megabytes' or `g' or `gigabytes' may
2548 also be used. For cputime the default scaling is `seconds',
2549 while `m' for minutes or `h' for hours, or a time of the form
2550 `mm:ss' giving minutes and seconds may be used.
2551 If maximum-use is `unlimited', then the limitation on the
2553 specified resource is removed (this is equivalent to the
2554 unlimit builtin command).
2555 For both resource names and scale factors, unambiguous prefixes
2557 of the names suffice.
2558 log (+) Prints the watch shell variable and reports on each user indi‐
2560 cated in watch who is logged in, regardless of when they last
2561 logged in. See also watchlog.
2562 login Terminates a login shell, replacing it with an instance of
2564 /bin/login. This is one way to log off, included for compati‐
2565 bility with sh(1).
2566 logout Terminates a login shell. Especially useful if ignoreeof is
2568 set.
2569 ls-F [-switch ...] [file ...] (+)
2571 Lists files like `ls -F', but much faster. It identifies each
2572 type of special file in the listing with a special character:
2573 / Directory
2575 * Executable
2576 # Block device
2577 % Character device
2578 | Named pipe (systems with named pipes only)
2579 = Socket (systems with sockets only)
2580 @ Symbolic link (systems with symbolic links only)
2581 + Hidden directory (AIX only) or context dependent (HP/UX
2582 only)
2583 : Network special (HP/UX only)
2584 If the listlinks shell variable is set, symbolic links are
2586 identified in more detail (on only systems that have them, of
2587 course):
2588 @ Symbolic link to a non-directory
2590 > Symbolic link to a directory
2591 & Symbolic link to nowhere
2592 listlinks also slows down ls-F and causes partitions holding
2594 files pointed to by symbolic links to be mounted.
2595 If the listflags shell variable is set to `x', `a' or `A', or
2597 any combination thereof (e.g., `xA'), they are used as flags to
2598 ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com‐
2599 bination (e.g., `ls -FxA'). On machines where `ls -C' is not
2600 the default, ls-F acts like `ls -CF', unless listflags contains
2601 an `x', in which case it acts like `ls -xF'. ls-F passes its
2602 arguments to ls(1) if it is given any switches, so `alias ls
2603 ls-F' generally does the right thing.
2604 The ls-F builtin can list files using different colors depend‐
2606 ing on the filetype or extension. See the color shell variable
2607 and the LS_COLORS environment variable.
2608 migrate [-site] pid|%jobid ... (+)
2610 migrate -site (+)
2611 The first form migrates the process or job to the site speci‐
2612 fied or the default site determined by the system path. The
2613 second form is equivalent to `migrate -site $$': it migrates
2614 the current process to the specified site. Migrating the shell
2615 itself can cause unexpected behavior, because the shell does
2616 not like to lose its tty. (TCF only)
2617 newgrp [-] [group] (+)
2619 Equivalent to `exec newgrp'; see newgrp(1). Available only if
2620 the shell was so compiled; see the version shell variable.
2621 nice [+number] [command]
2623 Sets the scheduling priority for the shell to number, or, with‐
2624 out number, to 4. With command, runs command at the appropri‐
2625 ate priority. The greater the number, the less cpu the process
2626 gets. The super-user may specify negative priority by using
2627 `nice -number ...'. Command is always executed in a sub-shell,
2628 and the restrictions placed on commands in simple if statements
2629 apply.
2630 nohup [command]
2632 With command, runs command such that it will ignore hangup sig‐
2633 nals. Note that commands may set their own response to
2634 hangups, overriding nohup. Without an argument, causes the
2635 non-interactive shell only to ignore hangups for the remainder
2636 of the script. See also Signal handling and the hup builtin
2637 command.
2638 notify [%job ...]
2640 Causes the shell to notify the user asynchronously when the
2641 status of any of the specified jobs (or, without %job, the cur‐
2642 rent job) changes, instead of waiting until the next prompt as
2643 is usual. job may be a number, a string, `', `%', `+' or `-'
2644 as described under Jobs. See also the notify shell variable.
2645 onintr [-|label]
2647 Controls the action of the shell on interrupts. Without argu‐
2648 ments, restores the default action of the shell on interrupts,
2649 which is to terminate shell scripts or to return to the termi‐
2650 nal command input level. With `-', causes all interrupts to be
2651 ignored. With label, causes the shell to execute a `goto
2652 label' when an interrupt is received or a child process termi‐
2653 nates because it was interrupted.
2654 onintr is ignored if the shell is running detached and in sys‐
2656 tem startup files (see FILES), where interrupts are disabled
2657 anyway.
2658 popd [-p] [-l] [-n|-v] [+n]
2660 Without arguments, pops the directory stack and returns to the
2661 new top directory. With a number `+n', discards the n'th entry
2662 in the stack.
2663 Finally, all forms of popd print the final directory stack,
2665 just like dirs. The pushdsilent shell variable can be set to
2666 prevent this and the -p flag can be given to override pushdsi‐
2667 lent. The -l, -n and -v flags have the same effect on popd as
2668 on dirs. (+)
2669 printenv [name] (+)
2671 Prints the names and values of all environment variables or,
2672 with name, the value of the environment variable name.
2673 pushd [-p] [-l] [-n|-v] [name|+n]
2675 Without arguments, exchanges the top two elements of the direc‐
2676 tory stack. If pushdtohome is set, pushd without arguments
2677 does `pushd ~', like cd. (+) With name, pushes the current
2678 working directory onto the directory stack and changes to name.
2679 If name is `-' it is interpreted as the previous working direc‐
2680 tory (see Filename substitution). (+) If dunique is set, pushd
2681 removes any instances of name from the stack before pushing it
2682 onto the stack. (+) With a number `+n', rotates the nth ele‐
2683 ment of the directory stack around to be the top element and
2684 changes to it. If dextract is set, however, `pushd +n'
2685 extracts the nth directory, pushes it onto the top of the stack
2686 and changes to it. (+)
2687 Finally, all forms of pushd print the final directory stack,
2689 just like dirs. The pushdsilent shell variable can be set to
2690 prevent this and the -p flag can be given to override pushdsi‐
2691 lent. The -l, -n and -v flags have the same effect on pushd as
2692 on dirs. (+)
2693 rehash Causes the internal hash table of the contents of the directo‐
2695 ries in the path variable to be recomputed. This is needed if
2696 the autorehash shell variable is not set and new commands are
2697 added to directories in path while you are logged in. With
2698 autorehash, a new command will be found automatically, except
2699 in the special case where another command of the same name
2700 which is located in a different directory already exists in the
2701 hash table. Also flushes the cache of home directories built
2702 by tilde expansion.
2703 repeat count command
2705 The specified command, which is subject to the same restric‐
2706 tions as the command in the one line if statement above, is
2707 executed count times. I/O redirections occur exactly once,
2708 even if count is 0.
2709 rootnode //nodename (+)
2711 Changes the rootnode to //nodename, so that `/' will be inter‐
2712 preted as `//nodename'. (Domain/OS only)
2713 sched (+)
2715 sched [+]hh:mm command (+)
2716 sched -n (+)
2717 The first form prints the scheduled-event list. The sched
2718 shell variable may be set to define the format in which the
2719 scheduled-event list is printed. The second form adds command
2720 to the scheduled-event list. For example,
2721 > sched 11:00 echo It\'s eleven o\'clock.
2723 causes the shell to echo `It's eleven o'clock.' at 11 AM. The
2725 time may be in 12-hour AM/PM format
2726 > sched 5pm set prompt='[%h] It\'s after 5; go home: >'
2728 or may be relative to the current time:
2730 > sched +2:15 /usr/lib/uucp/uucico -r1 -sother
2732 A relative time specification may not use AM/PM format. The
2734 third form removes item n from the event list:
2735 > sched
2737 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2738 2 Wed Apr 4 17:00 set prompt=[%h] It's after 5; go
2739 home: >
2740 > sched -2
2741 > sched
2742 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2743 A command in the scheduled-event list is executed just before
2745 the first prompt is printed after the time when the command is
2746 scheduled. It is possible to miss the exact time when the com‐
2747 mand is to be run, but an overdue command will execute at the
2748 next prompt. A command which comes due while the shell is
2749 waiting for user input is executed immediately. However, nor‐
2750 mal operation of an already-running command will not be inter‐
2751 rupted so that a scheduled-event list element may be run.
2752 This mechanism is similar to, but not the same as, the at(1)
2754 command on some Unix systems. Its major disadvantage is that
2755 it may not run a command at exactly the specified time. Its
2756 major advantage is that because sched runs directly from the
2757 shell, it has access to shell variables and other structures.
2758 This provides a mechanism for changing one's working environ‐
2759 ment based on the time of day.
2760 set
2762 set name ...
2763 set name=word ...
2764 set [-r] [-f|-l] name=(wordlist) ... (+)
2765 set name[index]=word ...
2766 set -r (+)
2767 set -r name ... (+)
2768 set -r name=word ... (+)
2769 The first form of the command prints the value of all shell
2770 variables. Variables which contain more than a single word
2771 print as a parenthesized word list. The second form sets name
2772 to the null string. The third form sets name to the single
2773 word. The fourth form sets name to the list of words in
2774 wordlist. In all cases the value is command and filename
2775 expanded. If -r is specified, the value is set read-only. If
2776 -f or -l are specified, set only unique words keeping their
2777 order. -f prefers the first occurrence of a word, and -l the
2778 last. The fifth form sets the index'th component of name to
2779 word; this component must already exist. The sixth form lists
2780 only the names of all shell variables that are read-only. The
2781 seventh form makes name read-only, whether or not it has a
2782 value. The eighth form is the same as the third form, but make
2783 name read-only at the same time.
2784 These arguments can be repeated to set and/or make read-only
2786 multiple variables in a single set command. Note, however,
2787 that variable expansion happens for all arguments before any
2788 setting occurs. Note also that `=' can be adjacent to both
2789 name and word or separated from both by whitespace, but cannot
2790 be adjacent to only one or the other. See also the unset
2791 builtin command.
2792 setenv [name [value]]
2794 Without arguments, prints the names and values of all environ‐
2795 ment variables. Given name, sets the environment variable name
2796 to value or, without value, to the null string.
2797 setpath path (+)
2799 Equivalent to setpath(1). (Mach only)
2800 setspath LOCAL|site|cpu ... (+)
2802 Sets the system execution path. (TCF only)
2803 settc cap value (+)
2805 Tells the shell to believe that the terminal capability cap (as
2806 defined in termcap(5)) has the value value. No sanity checking
2807 is done. Concept terminal users may have to `settc xn no' to
2808 get proper wrapping at the rightmost column.
2809 setty [-d|-q|-x] [-a] [[+|-]mode] (+)
2811 Controls which tty modes (see Terminal management) the shell
2812 does not allow to change. -d, -q or -x tells setty to act on
2813 the `edit', `quote' or `execute' set of tty modes respectively;
2814 without -d, -q or -x, `execute' is used.
2815 Without other arguments, setty lists the modes in the chosen
2817 set which are fixed on (`+mode') or off (`-mode'). The avail‐
2818 able modes, and thus the display, vary from system to system.
2819 With -a, lists all tty modes in the chosen set whether or not
2820 they are fixed. With +mode, -mode or mode, fixes mode on or
2821 off or removes control from mode in the chosen set. For exam‐
2822 ple, `setty +echok echoe' fixes `echok' mode on and allows com‐
2823 mands to turn `echoe' mode on or off, both when the shell is
2824 executing commands.
2825 setxvers [string] (+)
2827 Set the experimental version prefix to string, or removes it if
2828 string is omitted. (TCF only)
2829 shift [variable]
2831 Without arguments, discards argv[1] and shifts the members of
2832 argv to the left. It is an error for argv not to be set or to
2833 have less than one word as value. With variable, performs the
2834 same function on variable.
2835 source [-h] name [args ...]
2837 The shell reads and executes commands from name. The commands
2838 are not placed on the history list. If any args are given,
2839 they are placed in argv. (+) source commands may be nested; if
2840 they are nested too deeply the shell may run out of file
2841 descriptors. An error in a source at any level terminates all
2842 nested source commands. With -h, commands are placed on the
2843 history list instead of being executed, much like `history -L'.
2844 stop %job|pid ...
2846 Stops the specified jobs or processes which are executing in
2847 the background. job may be a number, a string, `', `%', `+' or
2848 `-' as described under Jobs. There is no default job; saying
2849 just `stop' does not stop the current job.
2850 suspend Causes the shell to stop in its tracks, much as if it had been
2852 sent a stop signal with ^Z. This is most often used to stop
2853 shells started by su(1).
2854 switch (string)
2856 case str1:
2857 ...
2858 breaksw
2859 ...
2860 default:
2861 ...
2862 breaksw
2863 endsw Each case label is successively matched, against the specified
2864 string which is first command and filename expanded. The file
2865 metacharacters `*', `?' and `[...]' may be used in the case
2866 labels, which are variable expanded. If none of the labels
2867 match before a `default' label is found, then the execution
2868 begins after the default label. Each case label and the
2869 default label must appear at the beginning of a line. The com‐
2870 mand breaksw causes execution to continue after the endsw.
2871 Otherwise control may fall through case labels and default
2872 labels as in C. If no label matches and there is no default,
2873 execution continues after the endsw.
2874 telltc (+)
2876 Lists the values of all terminal capabilities (see termcap(5)).
2877 termname [terminal type] (+)
2879 Tests if terminal type (or the current value of TERM if no ter‐
2880 minal type is given) has an entry in the hosts termcap(5) or
2881 terminfo(5) database. Prints the terminal type to stdout and
2882 returns 0 if an entry is present otherwise returns 1.
2883 time [command]
2885 Executes command (which must be a simple command, not an alias,
2886 a pipeline, a command list or a parenthesized command list) and
2887 prints a time summary as described under the time variable. If
2888 necessary, an extra shell is created to print the time statis‐
2889 tic when the command completes. Without command, prints a time
2890 summary for the current shell and its children.
2891 umask [value]
2893 Sets the file creation mask to value, which is given in octal.
2894 Common values for the mask are 002, giving all access to the
2895 group and read and execute access to others, and 022, giving
2896 read and execute access to the group and others. Without
2897 value, prints the current file creation mask.
2898 unalias pattern
2900 Removes all aliases whose names match pattern. `unalias *'
2901 thus removes all aliases. It is not an error for nothing to be
2902 unaliased.
2903 uncomplete pattern (+)
2905 Removes all completions whose names match pattern. `uncomplete
2906 *' thus removes all completions. It is not an error for noth‐
2907 ing to be uncompleted.
2908 unhash Disables use of the internal hash table to speed location of
2910 executed programs.
2911 universe universe (+)
2913 Sets the universe to universe. (Masscomp/RTU only)
2914 unlimit [-hf] [resource]
2916 Removes the limitation on resource or, if no resource is speci‐
2917 fied, all resource limitations. With -h, the corresponding
2918 hard limits are removed. Only the super-user may do this.
2919 Note that unlimit may not exit successful, since most systems
2920 do not allow descriptors to be unlimited. With -f errors are
2921 ignored.
2922 unset pattern
2924 Removes all variables whose names match pattern, unless they
2925 are read-only. `unset *' thus removes all variables unless
2926 they are read-only; this is a bad idea. It is not an error for
2927 nothing to be unset.
2928 unsetenv pattern
2930 Removes all environment variables whose names match pattern.
2931 `unsetenv *' thus removes all environment variables; this is a
2932 bad idea. It is not an error for nothing to be unsetenved.
2933 ver [systype [command]] (+)
2935 Without arguments, prints SYSTYPE. With systype, sets SYSTYPE
2936 to systype. With systype and command, executes command under
2937 systype. systype may be `bsd4.3' or `sys5.3'. (Domain/OS
2938 only)
2939 wait The shell waits for all background jobs. If the shell is
2941 interactive, an interrupt will disrupt the wait and cause the
2942 shell to print the names and job numbers of all outstanding
2943 jobs.
2944 warp universe (+)
2946 Sets the universe to universe. (Convex/OS only)
2947 watchlog (+)
2949 An alternate name for the log builtin command (q.v.). Avail‐
2950 able only if the shell was so compiled; see the version shell
2951 variable.
2952 where command (+)
2954 Reports all known instances of command, including aliases,
2955 builtins and executables in path.
2956 which command (+)
2958 Displays the command that will be executed by the shell after
2959 substitutions, path searching, etc. The builtin command is
2960 just like which(1), but it correctly reports tcsh aliases and
2961 builtins and is 10 to 100 times faster. See also the which-
2962 command editor command.
2963 while (expr)
2965 ...
2966 end Executes the commands between the while and the matching end
2967 while expr (an expression, as described under Expressions)
2968 evaluates non-zero. while and end must appear alone on their
2969 input lines. break and continue may be used to terminate or
2970 continue the loop prematurely. If the input is a terminal, the
2971 user is prompted the first time through the loop as with fore‐
2972 ach.
2973 Special aliases (+)
2975 If set, each of these aliases executes automatically at the indicated
2976 time. They are all initially undefined.
2977 beepcmd Runs when the shell wants to ring the terminal bell.
2979 cwdcmd Runs after every change of working directory. For example, if
2981 the user is working on an X window system using xterm(1) and a
2982 re-parenting window manager that supports title bars such as
2983 twm(1) and does
2984 > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd ^G"'
2986 then the shell will change the title of the running xterm(1) to
2988 be the name of the host, a colon, and the full current working
2989 directory. A fancier way to do that is
2990 > alias cwdcmd 'echo -n
2992 "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'
2993 This will put the hostname and working directory on the title
2995 bar but only the hostname in the icon manager menu.
2996 Note that putting a cd, pushd or popd in cwdcmd may cause an
2998 infinite loop. It is the author's opinion that anyone doing so
2999 will get what they deserve.
3000 jobcmd Runs before each command gets executed, or when the command
3002 changes state. This is similar to postcmd, but it does not
3003 print builtins.
3004 > alias jobcmd 'echo -n "^[]2\;\!#:q^G"'
3006 then executing vi foo.c will put the command string in the
3008 xterm title bar.
3009 helpcommand
3011 Invoked by the run-help editor command. The command name for
3012 which help is sought is passed as sole argument. For example,
3013 if one does
3014 > alias helpcommand '\!:1 --help'
3016 then the help display of the command itself will be invoked,
3018 using the GNU help calling convention. Currently there is no
3019 easy way to account for various calling conventions (e.g., the
3020 customary Unix `-h'), except by using a table of many commands.
3021 periodic
3023 Runs every tperiod minutes. This provides a convenient means
3024 for checking on common but infrequent changes such as new mail.
3025 For example, if one does
3026 > set tperiod = 30
3028 > alias periodic checknews
3029 then the checknews(1) program runs every 30 minutes. If peri‐
3031 odic is set but tperiod is unset or set to 0, periodic behaves
3032 like precmd.
3033 precmd Runs just before each prompt is printed. For example, if one
3035 does
3036 > alias precmd date
3038 then date(1) runs just before the shell prompts for each com‐
3040 mand. There are no limits on what precmd can be set to do, but
3041 discretion should be used.
3042 postcmd Runs before each command gets executed.
3044 > alias postcmd 'echo -n "^[]2\;\!#:q^G"'
3046 then executing vi foo.c will put the command string in the
3048 xterm title bar.
3049 shell Specifies the interpreter for executable scripts which do not
3051 themselves specify an interpreter. The first word should be a
3052 full path name to the desired interpreter (e.g., `/bin/csh' or
3053 `/usr/local/bin/tcsh').
3054 Special shell variables
3056 The variables described in this section have special meaning to the
3057 shell.
3058 The shell sets addsuffix, argv, autologout, csubstnonl, command,
3060 echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
3061 prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
3062 at startup; they do not change thereafter unless changed by the user.
3063 The shell updates cwd, dirstack, owd and status when necessary, and
3064 sets logout on logout.
3065 The shell synchronizes group, home, path, shlvl, term and user with the
3067 environment variables of the same names: whenever the environment vari‐
3068 able changes the shell changes the corresponding shell variable to
3069 match (unless the shell variable is read-only) and vice versa. Note
3070 that although cwd and PWD have identical meanings, they are not syn‐
3071 chronized in this manner, and that the shell automatically converts
3072 between the different formats of path and PATH.
3073 addsuffix (+)
3075 If set, filename completion adds `/' to the end of directories
3076 and a space to the end of normal files when they are matched
3077 exactly. Set by default.
3078 afsuser (+)
3080 If set, autologout's autolock feature uses its value instead of
3081 the local username for kerberos authentication.
3082 ampm (+)
3084 If set, all times are shown in 12-hour AM/PM format.
3085 anyerror (+)
3087 This variable selects what is propagated to the value of the
3088 status variable. For more information see the description of
3089 the status variable below.
3090 argv The arguments to the shell. Positional parameters are taken
3092 from argv, i.e., `$1' is replaced by `$argv[1]', etc. Set by
3093 default, but usually empty in interactive shells.
3094 autocorrect (+)
3096 If set, the spell-word editor command is invoked automatically
3097 before each completion attempt.
3098 autoexpand (+)
3100 If set, the expand-history editor command is invoked automati‐
3101 cally before each completion attempt. If this is set to only‐
3102 history, then only history will be expanded and a second com‐
3103 pletion will expand filenames.
3104 autolist (+)
3106 If set, possibilities are listed after an ambiguous completion.
3107 If set to `ambiguous', possibilities are listed only when no
3108 new characters are added by completion.
3109 autologout (+)
3111 The first word is the number of minutes of inactivity before
3112 automatic logout. The optional second word is the number of
3113 minutes of inactivity before automatic locking. When the shell
3114 automatically logs out, it prints `auto-logout', sets the vari‐
3115 able logout to `automatic' and exits. When the shell automati‐
3116 cally locks, the user is required to enter his password to con‐
3117 tinue working. Five incorrect attempts result in automatic
3118 logout. Set to `60' (automatic logout after 60 minutes, and no
3119 locking) by default in login and superuser shells, but not if
3120 the shell thinks it is running under a window system (i.e., the
3121 DISPLAY environment variable is set), the tty is a pseudo-tty
3122 (pty) or the shell was not so compiled (see the version shell
3123 variable). Unset or set to `0' to disable automatic logout.
3124 See also the afsuser and logout shell variables.
3125 autorehash (+)
3127 If set, the internal hash table of the contents of the directo‐
3128 ries in the path variable will be recomputed if a command is
3129 not found in the hash table. In addition, the list of avail‐
3130 able commands will be rebuilt for each command completion or
3131 spelling correction attempt if set to `complete' or `correct'
3132 respectively; if set to `always', this will be done for both
3133 cases.
3134 backslash_quote (+)
3136 If set, backslashes (`\') always quote `\', `'', and `"'. This
3137 may make complex quoting tasks easier, but it can cause syntax
3138 errors in csh(1) scripts.
3139 catalog The file name of the message catalog. If set, tcsh use
3141 `tcsh.${catalog}' as a message catalog instead of default
3142 `tcsh'.
3143 cdpath A list of directories in which cd should search for subdirecto‐
3145 ries if they aren't found in the current directory.
3146 cdtohome (+)
3148 If not set, cd requires a directory name, and will not go to
3149 the home directory if it's omitted. This is set by default.
3150 color If set, it enables color display for the builtin ls-F and it
3152 passes --color=auto to ls. Alternatively, it can be set to
3153 only ls-F or only ls to enable color to only one command. Set‐
3154 ting it to nothing is equivalent to setting it to (ls-F ls).
3155 colorcat
3157 If set, it enables color escape sequence for NLS message files.
3158 And display colorful NLS messages.
3159 command (+)
3161 If set, the command which was passed to the shell with the -c
3162 flag (q.v.).
3163 compat_expr (+)
3165 If set, the shell will evaluate expressions right to left, like
3166 the original csh.
3167 complete (+)
3169 If set to `igncase', the completion becomes case insensitive.
3170 If set to `enhance', completion ignores case and considers
3171 hyphens and underscores to be equivalent; it will also treat
3172 periods, hyphens and underscores (`.', `-' and `_') as word
3173 separators. If set to `Enhance', completion matches uppercase
3174 and underscore characters explicitly and matches lowercase and
3175 hyphens in a case-insensitive manner; it will treat periods,
3176 hyphens and underscores as word separators.
3177 continue (+)
3179 If set to a list of commands, the shell will continue the
3180 listed commands, instead of starting a new one.
3181 continue_args (+)
3183 Same as continue, but the shell will execute:
3184 echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>
3186 correct (+)
3188 If set to `cmd', commands are automatically spelling-corrected.
3189 If set to `complete', commands are automatically completed. If
3190 set to `all', the entire command line is corrected.
3191 csubstnonl (+)
3193 If set, newlines and carriage returns in command substitution
3194 are replaced by spaces. Set by default.
3195 cwd The full pathname of the current directory. See also the
3197 dirstack and owd shell variables.
3198 dextract (+)
3200 If set, `pushd +n' extracts the nth directory from the direc‐
3201 tory stack rather than rotating it to the top.
3202 dirsfile (+)
3204 The default location in which `dirs -S' and `dirs -L' look for
3205 a history file. If unset, ~/.cshdirs is used. Because only
3206 ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
3207 should be set in ~/.tcshrc rather than ~/.login.
3208 dirstack (+)
3210 An array of all the directories on the directory stack.
3211 `$dirstack[1]' is the current working directory, `$dirstack[2]'
3212 the first directory on the stack, etc. Note that the current
3213 working directory is `$dirstack[1]' but `=0' in directory stack
3214 substitutions, etc. One can change the stack arbitrarily by
3215 setting dirstack, but the first element (the current working
3216 directory) is always correct. See also the cwd and owd shell
3217 variables.
3218 dspmbyte (+)
3220 Has an effect iff 'dspm' is listed as part of the version shell
3221 variable. If set to `euc', it enables display and editing EUC-
3222 kanji(Japanese) code. If set to `sjis', it enables display and
3223 editing Shift-JIS(Japanese) code. If set to `big5', it enables
3224 display and editing Big5(Chinese) code. If set to `utf8', it
3225 enables display and editing Utf8(Unicode) code. If set to the
3226 following format, it enables display and editing of original
3227 multi-byte code format:
3228 > set dspmbyte = 0000....(256 bytes)....0000
3230 The table requires just 256 bytes. Each character of 256 char‐
3232 acters corresponds (from left to right) to the ASCII codes
3233 0x00, 0x01, ... 0xff. Each character is set to number 0,1,2
3234 and 3. Each number has the following meaning:
3235 0 ... not used for multi-byte characters.
3236 1 ... used for the first byte of a multi-byte character.
3237 2 ... used for the second byte of a multi-byte character.
3238 3 ... used for both the first byte and second byte of a
3239 multi-byte character.
3240 Example:
3242 If set to `001322', the first character (means 0x00 of the
3243 ASCII code) and second character (means 0x01 of ASCII code) are
3244 set to `0'. Then, it is not used for multi-byte characters.
3245 The 3rd character (0x02) is set to '1', indicating that it is
3246 used for the first byte of a multi-byte character. The 4th
3247 character(0x03) is set '3'. It is used for both the first byte
3248 and the second byte of a multi-byte character. The 5th and 6th
3249 characters (0x04,0x05) are set to '2', indicating that they are
3250 used for the second byte of a multi-byte character.
3251 The GNU fileutils version of ls cannot display multi-byte file‐
3253 names without the -N ( --literal ) option. If you are using
3254 this version, set the second word of dspmbyte to "ls". If not,
3255 for example, "ls-F -l" cannot display multi-byte filenames.
3256 Note:
3258 This variable can only be used if KANJI and DSPMBYTE has been
3259 defined at compile time.
3260 dunique (+)
3262 If set, pushd removes any instances of name from the stack
3263 before pushing it onto the stack.
3264 echo If set, each command with its arguments is echoed just before
3266 it is executed. For non-builtin commands all expansions occur
3267 before echoing. Builtin commands are echoed before command and
3268 filename substitution, because these substitutions are then
3269 done selectively. Set by the -x command line option.
3270 echo_style (+)
3272 The style of the echo builtin. May be set to
3273 bsd Don't echo a newline if the first argument is `-n'; the
3275 default for csh.
3276 sysv Recognize backslashed escape sequences in echo strings.
3277 both Recognize both the `-n' flag and backslashed escape
3278 sequences; the default for tcsh.
3279 none Recognize neither.
3280 Set by default to the local system default. The BSD and System
3282 V options are described in the echo(1) man pages on the appro‐
3283 priate systems.
3284 edit (+)
3286 If set, the command-line editor is used. Set by default in
3287 interactive shells.
3288 editors (+)
3290 A list of command names for the run-fg-editor editor command to
3291 match. If not set, the EDITOR (`ed' if unset) and VISUAL (`vi'
3292 if unset) environment variables will be used instead.
3293 ellipsis (+)
3295 If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
3296 shell variable) indicate skipped directories with an ellipsis
3297 (`...') instead of `/<skipped>'.
3298 euid (+)
3300 The user's effective user ID.
3301 euser (+)
3303 The first matching passwd entry name corresponding to the
3304 effective user ID.
3305 fignore (+)
3307 Lists file name suffixes to be ignored by completion.
3308 filec In tcsh, completion is always used and this variable is ignored
3310 by default. If edit is unset, then the traditional csh comple‐
3311 tion is used. If set in csh, filename completion is used.
3312 gid (+) The user's real group ID.
3314 globdot (+)
3316 If set, wild-card glob patterns will match files and directo‐
3317 ries beginning with `.' except for `.' and `..'
3318 globstar (+)
3320 If set, the `**' and `***' file glob patterns will match any
3321 string of characters including `/' traversing any existing sub-
3322 directories. (e.g. `ls **.c' will list all the .c files in
3323 the current directory tree). If used by itself, it will match
3324 zero or more sub-directories (e.g. `ls /usr/include/**/time.h'
3325 will list any file named `time.h' in the /usr/include directory
3326 tree; whereas `ls /usr/include/**time.h' will match any file in
3327 the /usr/include directory tree ending in `time.h'). To pre‐
3328 vent problems with recursion, the `**' glob-pattern will not
3329 descend into a symbolic link containing a directory. To over‐
3330 ride this, use `***'
3331 group (+)
3333 The user's group name.
3334 highlight
3336 If set, the incremental search match (in i-search-back and i-
3337 search-fwd) and the region between the mark and the cursor are
3338 highlighted in reverse video.
3339 Highlighting requires more frequent terminal writes, which
3341 introduces extra overhead. If you care about terminal perfor‐
3342 mance, you may want to leave this unset.
3343 histchars
3345 A string value determining the characters used in History sub‐
3346 stitution (q.v.). The first character of its value is used as
3347 the history substitution character, replacing the default char‐
3348 acter `!'. The second character of its value replaces the
3349 character `^' in quick substitutions.
3350 histdup (+)
3352 Controls handling of duplicate entries in the history list. If
3353 set to `all' only unique history events are entered in the his‐
3354 tory list. If set to `prev' and the last history event is the
3355 same as the current command, then the current command is not
3356 entered in the history. If set to `erase' and the same event
3357 is found in the history list, that old event gets erased and
3358 the current one gets inserted. Note that the `prev' and `all'
3359 options renumber history events so there are no gaps.
3360 histfile (+)
3362 The default location in which `history -S' and `history -L'
3363 look for a history file. If unset, ~/.history is used. hist‐
3364 file is useful when sharing the same home directory between
3365 different machines, or when saving separate histories on dif‐
3366 ferent terminals. Because only ~/.tcshrc is normally sourced
3367 before ~/.history, histfile should be set in ~/.tcshrc rather
3368 than ~/.login.
3369 histlit (+)
3371 If set, builtin and editor commands and the savehist mechanism
3372 use the literal (unexpanded) form of lines in the history list.
3373 See also the toggle-literal-history editor command.
3374 history The first word indicates the number of history events to save.
3376 The optional second word (+) indicates the format in which his‐
3377 tory is printed; if not given, `%h\t%T\t%R\n' is used. The
3378 format sequences are described below under prompt; note the
3379 variable meaning of `%R'. Set to `100' by default.
3380 home Initialized to the home directory of the invoker. The filename
3382 expansion of `~' refers to this variable.
3383 ignoreeof
3385 If set to the empty string or `0' and the input device is a
3386 terminal, the end-of-file command (usually generated by the
3387 user by typing `^D' on an empty line) causes the shell to print
3388 `Use "exit" to leave tcsh.' instead of exiting. This prevents
3389 the shell from accidentally being killed. Historically this
3390 setting exited after 26 successive EOF's to avoid infinite
3391 loops. If set to a number n, the shell ignores n - 1 consecu‐
3392 tive end-of-files and exits on the nth. (+) If unset, `1' is
3393 used, i.e., the shell exits on a single `^D'.
3394 implicitcd (+)
3396 If set, the shell treats a directory name typed as a command as
3397 though it were a request to change to that directory. If set
3398 to verbose, the change of directory is echoed to the standard
3399 output. This behavior is inhibited in non-interactive shell
3400 scripts, or for command strings with more than one word.
3401 Changing directory takes precedence over executing a like-named
3402 command, but it is done after alias substitutions. Tilde and
3403 variable expansions work as expected.
3404 inputmode (+)
3406 If set to `insert' or `overwrite', puts the editor into that
3407 input mode at the beginning of each line.
3408 killdup (+)
3410 Controls handling of duplicate entries in the kill ring. If
3411 set to `all' only unique strings are entered in the kill ring.
3412 If set to `prev' and the last killed string is the same as the
3413 current killed string, then the current string is not entered
3414 in the ring. If set to `erase' and the same string is found in
3415 the kill ring, the old string is erased and the current one is
3416 inserted.
3417 killring (+)
3419 Indicates the number of killed strings to keep in memory. Set
3420 to `30' by default. If unset or set to less than `2', the
3421 shell will only keep the most recently killed string. Strings
3422 are put in the killring by the editor commands that delete
3423 (kill) strings of text, e.g. backward-delete-word, kill-line,
3424 etc, as well as the copy-region-as-kill command. The yank edi‐
3425 tor command will yank the most recently killed string into the
3426 command-line, while yank-pop (see Editor commands) can be used
3427 to yank earlier killed strings.
3428 listflags (+)
3430 If set to `x', `a' or `A', or any combination thereof (e.g.,
3431 `xA'), they are used as flags to ls-F, making it act like `ls
3432 -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
3433 `a' shows all files (even if they start with a `.'), `A' shows
3434 all files but `.' and `..', and `x' sorts across instead of
3435 down. If the second word of listflags is set, it is used as
3436 the path to `ls(1)'.
3437 listjobs (+)
3439 If set, all jobs are listed when a job is suspended. If set to
3440 `long', the listing is in long format.
3441 listlinks (+)
3443 If set, the ls-F builtin command shows the type of file to
3444 which each symbolic link points.
3445 listmax (+)
3447 The maximum number of items which the list-choices editor com‐
3448 mand will list without asking first.
3449 listmaxrows (+)
3451 The maximum number of rows of items which the list-choices edi‐
3452 tor command will list without asking first.
3453 loginsh (+)
3455 Set by the shell if it is a login shell. Setting or unsetting
3456 it within a shell has no effect. See also shlvl.
3457 logout (+)
3459 Set by the shell to `normal' before a normal logout, `auto‐
3460 matic' before an automatic logout, and `hangup' if the shell
3461 was killed by a hangup signal (see Signal handling). See also
3462 the autologout shell variable.
3463 mail A list of files and directories to check for incoming mail,
3465 optionally preceded by a numeric word. Before each prompt, if
3466 10 minutes have passed since the last check, the shell checks
3467 each file and says `You have new mail.' (or, if mail contains
3468 multiple files, `You have new mail in name.') if the filesize
3469 is greater than zero in size and has a modification time
3470 greater than its access time.
3471 If you are in a login shell, then no mail file is reported
3473 unless it has been modified after the time the shell has
3474 started up, to prevent redundant notifications. Most login
3475 programs will tell you whether or not you have mail when you
3476 log in.
3477 If a file specified in mail is a directory, the shell will
3479 count each file within that directory as a separate message,
3480 and will report `You have n mails.' or `You have n mails in
3481 name.' as appropriate. This functionality is provided primar‐
3482 ily for those systems which store mail in this manner, such as
3483 the Andrew Mail System.
3484 If the first word of mail is numeric it is taken as a different
3486 mail checking interval, in seconds.
3487 Under very rare circumstances, the shell may report `You have
3489 mail.' instead of `You have new mail.'
3490 matchbeep (+)
3492 If set to `never', completion never beeps. If set to
3493 `nomatch', it beeps only when there is no match. If set to
3494 `ambiguous', it beeps when there are multiple matches. If set
3495 to `notunique', it beeps when there is one exact and other
3496 longer matches. If unset, `ambiguous' is used.
3497 nobeep (+)
3499 If set, beeping is completely disabled. See also visiblebell.
3500 noclobber
3502 If set, restrictions are placed on output redirection to insure
3503 that files are not accidentally destroyed and that `>>' redi‐
3504 rections refer to existing files, as described in the
3505 Input/output section.
3506 noding If set, disable the printing of `DING!' in the prompt time
3508 specifiers at the change of hour.
3509 noglob If set, Filename substitution and Directory stack substitution
3511 (q.v.) are inhibited. This is most useful in shell scripts
3512 which do not deal with filenames, or after a list of filenames
3513 has been obtained and further expansions are not desirable.
3514 nokanji (+)
3516 If set and the shell supports Kanji (see the version shell
3517 variable), it is disabled so that the meta key can be used.
3518 nonomatch
3520 If set, a Filename substitution or Directory stack substitution
3521 (q.v.) which does not match any existing files is left
3522 untouched rather than causing an error. It is still an error
3523 for the substitution to be malformed, e.g., `echo [' still
3524 gives an error.
3525 nostat (+)
3527 A list of directories (or glob-patterns which match directo‐
3528 ries; see Filename substitution) that should not be stat(2)ed
3529 during a completion operation. This is usually used to exclude
3530 directories which take too much time to stat(2), for example
3531 /afs.
3532 notify If set, the shell announces job completions asynchronously.
3534 The default is to present job completions just before printing
3535 a prompt.
3536 oid (+) The user's real organization ID. (Domain/OS only)
3538 owd (+) The old working directory, equivalent to the `-' used by cd and
3540 pushd. See also the cwd and dirstack shell variables.
3541 padhour If set, enable the printing of padding '0' for hours, in 24 and
3543 12 hour formats. E.G.: 07:45:42 vs. 7:45:42.
3544 parseoctal
3546 To retain compatibily with older versions numeric variables
3547 starting with 0 are not interpreted as octal. Setting this
3548 variable enables proper octal parsing.
3549 path A list of directories in which to look for executable commands.
3551 A null word specifies the current directory. If there is no
3552 path variable then only full path names will execute. path is
3553 set by the shell at startup from the PATH environment variable
3554 or, if PATH does not exist, to a system-dependent default some‐
3555 thing like `(/usr/local/bin /usr/bsd /bin /usr/bin .)'. The
3556 shell may put `.' first or last in path or omit it entirely
3557 depending on how it was compiled; see the version shell vari‐
3558 able. A shell which is given neither the -c nor the -t option
3559 hashes the contents of the directories in path after reading
3560 ~/.tcshrc and each time path is reset. If one adds a new com‐
3561 mand to a directory in path while the shell is active, one may
3562 need to do a rehash for the shell to find it.
3563 printexitvalue (+)
3565 If set and an interactive program exits with a non-zero status,
3566 the shell prints `Exit status'.
3567 prompt The string which is printed before reading each command from
3569 the terminal. prompt may include any of the following format‐
3570 ting sequences (+), which are replaced by the given informa‐
3571 tion:
3572 %/ The current working directory.
3574 %~ The current working directory, but with one's home direc‐
3575 tory represented by `~' and other users' home directories
3576 represented by `~user' as per Filename substitution.
3577 `~user' substitution happens only if the shell has already
3578 used `~user' in a pathname in the current session.
3579 %c[[0]n], %.[[0]n]
3580 The trailing component of the current working directory, or
3581 n trailing components if a digit n is given. If n begins
3582 with `0', the number of skipped components precede the
3583 trailing component(s) in the format `/<skipped>trailing'.
3584 If the ellipsis shell variable is set, skipped components
3585 are represented by an ellipsis so the whole becomes
3586 `...trailing'. `~' substitution is done as in `%~' above,
3587 but the `~' component is ignored when counting trailing
3588 components.
3589 %C Like %c, but without `~' substitution.
3590 %h, %!, !
3591 The current history event number.
3592 %M The full hostname.
3593 %m The hostname up to the first `.'.
3594 %S (%s)
3595 Start (stop) standout mode.
3596 %B (%b)
3597 Start (stop) boldfacing mode.
3598 %U (%u)
3599 Start (stop) underline mode.
3600 %t, %@
3601 The time of day in 12-hour AM/PM format.
3602 %T Like `%t', but in 24-hour format (but see the ampm shell
3603 variable).
3604 %p The `precise' time of day in 12-hour AM/PM format, with
3605 seconds.
3606 %P Like `%p', but in 24-hour format (but see the ampm shell
3607 variable).
3608 \c c is parsed as in bindkey.
3609 ^c c is parsed as in bindkey.
3610 %% A single `%'.
3611 %n The user name.
3612 %N The effective user name.
3613 %j The number of jobs.
3614 %d The weekday in `Day' format.
3615 %D The day in `dd' format.
3616 %w The month in `Mon' format.
3617 %W The month in `mm' format.
3618 %y The year in `yy' format.
3619 %Y The year in `yyyy' format.
3620 %l The shell's tty.
3621 %L Clears from the end of the prompt to end of the display or
3622 the end of the line.
3623 %$ Expands the shell or environment variable name immediately
3624 after the `$'.
3625 %# `>' (or the first character of the promptchars shell vari‐
3626 able) for normal users, `#' (or the second character of
3627 promptchars) for the superuser.
3628 %{string%}
3629 Includes string as a literal escape sequence. It should be
3630 used only to change terminal attributes and should not move
3631 the cursor location. This cannot be the last sequence in
3632 prompt.
3633 %? The return code of the command executed just before the
3634 prompt.
3635 %R In prompt2, the status of the parser. In prompt3, the cor‐
3636 rected string. In history, the history string.
3637 `%B', `%S', `%U' and `%{string%}' are available in only eight-
3639 bit-clean shells; see the version shell variable.
3640 The bold, standout and underline sequences are often used to
3642 distinguish a superuser shell. For example,
3643 > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
3645 tut [37] [2:54pm] [/usr/accts/sys] you rang? _
3646 If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
3648 set, then print `DING!' on the change of hour (i.e, `:00' min‐
3649 utes) instead of the actual time.
3650 Set by default to `%# ' in interactive shells.
3652 prompt2 (+)
3654 The string with which to prompt in while and foreach loops and
3655 after lines ending in `\'. The same format sequences may be
3656 used as in prompt (q.v.); note the variable meaning of `%R'.
3657 Set by default to `%R? ' in interactive shells.
3658 prompt3 (+)
3660 The string with which to prompt when confirming automatic
3661 spelling correction. The same format sequences may be used as
3662 in prompt (q.v.); note the variable meaning of `%R'. Set by
3663 default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.
3664 promptchars (+)
3666 If set (to a two-character string), the `%#' formatting
3667 sequence in the prompt shell variable is replaced with the
3668 first character for normal users and the second character for
3669 the superuser.
3670 pushdtohome (+)
3672 If set, pushd without arguments does `pushd ~', like cd.
3673 pushdsilent (+)
3675 If set, pushd and popd do not print the directory stack.
3676 recexact (+)
3678 If set, completion completes on an exact match even if a longer
3679 match is possible.
3680 recognize_only_executables (+)
3682 If set, command listing displays only files in the path that
3683 are executable. Slow.
3684 rmstar (+)
3686 If set, the user is prompted before `rm *' is executed.
3687 rprompt (+)
3689 The string to print on the right-hand side of the screen (after
3690 the command input) when the prompt is being displayed on the
3691 left. It recognizes the same formatting characters as prompt.
3692 It will automatically disappear and reappear as necessary, to
3693 ensure that command input isn't obscured, and will appear only
3694 if the prompt, command input, and itself will fit together on
3695 the first line. If edit isn't set, then rprompt will be
3696 printed after the prompt and before the command input.
3697 savedirs (+)
3699 If set, the shell does `dirs -S' before exiting. If the first
3700 word is set to a number, at most that many directory stack
3701 entries are saved.
3702 savehist
3704 If set, the shell does `history -S' before exiting. If the
3705 first word is set to a number, at most that many lines are
3706 saved. (The number should be less than or equal to the number
3707 history entries; if it is set to greater than the number of
3708 history settings, only history entries will be saved) If the
3709 second word is set to `merge', the history list is merged with
3710 the existing history file instead of replacing it (if there is
3711 one) and sorted by time stamp and the most recent events are
3712 retained. If the second word of savehist is `merge' and the
3713 third word is set to `lock', the history file update will be
3714 serialized with other shell sessions that would possibly like
3715 to merge history at exactly the same time. (+)
3716 sched (+)
3718 The format in which the sched builtin command prints scheduled
3719 events; if not given, `%h\t%T\t%R\n' is used. The format
3720 sequences are described above under prompt; note the variable
3721 meaning of `%R'.
3722 shell The file in which the shell resides. This is used in forking
3724 shells to interpret files which have execute bits set, but
3725 which are not executable by the system. (See the description
3726 of Builtin and non-builtin command execution.) Initialized to
3727 the (system-dependent) home of the shell.
3728 shlvl (+)
3730 The number of nested shells. Reset to 1 in login shells. See
3731 also loginsh.
3732 status The exit status from the last command or backquote expansion,
3734 or any command in a pipeline is propagated to status. (This is
3735 also the default csh behavior.) This default does not match
3736 what POSIX mandates (to return the status of the last command
3737 only). To match the POSIX behavior, you need to unset anyerror.
3738 If the anyerror variable is unset, the exit status of a pipe‐
3740 line is determined only from the last command in the pipeline,
3741 and the exit status of a backquote expansion is not propagated
3742 to status.
3743 If a command terminated abnormally, then 0200 is added to the
3745 status. Builtin commands which fail return exit status `1',
3746 all other builtin commands return status `0'.
3747 symlinks (+)
3749 Can be set to several different values to control symbolic link
3750 (`symlink') resolution:
3751 If set to `chase', whenever the current directory changes to a
3753 directory containing a symbolic link, it is expanded to the
3754 real name of the directory to which the link points. This does
3755 not work for the user's home directory; this is a bug.
3756 If set to `ignore', the shell tries to construct a current
3758 directory relative to the current directory before the link was
3759 crossed. This means that cding through a symbolic link and
3760 then `cd ..'ing returns one to the original directory. This
3761 affects only builtin commands and filename completion.
3762 If set to `expand', the shell tries to fix symbolic links by
3764 actually expanding arguments which look like path names. This
3765 affects any command, not just builtins. Unfortunately, this
3766 does not work for hard-to-recognize filenames, such as those
3767 embedded in command options. Expansion may be prevented by
3768 quoting. While this setting is usually the most convenient, it
3769 is sometimes misleading and sometimes confusing when it fails
3770 to recognize an argument which should be expanded. A compro‐
3771 mise is to use `ignore' and use the editor command normalize-
3772 path (bound by default to ^X-n) when necessary.
3773 Some examples are in order. First, let's set up some play
3775 directories:
3776 > cd /tmp
3778 > mkdir from from/src to
3779 > ln -s from/src to/dst
3780 Here's the behavior with symlinks unset,
3782 > cd /tmp/to/dst; echo $cwd
3784 /tmp/to/dst
3785 > cd ..; echo $cwd
3786 /tmp/from
3787 here's the behavior with symlinks set to `chase',
3789 > cd /tmp/to/dst; echo $cwd
3791 /tmp/from/src
3792 > cd ..; echo $cwd
3793 /tmp/from
3794 here's the behavior with symlinks set to `ignore',
3796 > cd /tmp/to/dst; echo $cwd
3798 /tmp/to/dst
3799 > cd ..; echo $cwd
3800 /tmp/to
3801 and here's the behavior with symlinks set to `expand'.
3803 > cd /tmp/to/dst; echo $cwd
3805 /tmp/to/dst
3806 > cd ..; echo $cwd
3807 /tmp/to
3808 > cd /tmp/to/dst; echo $cwd
3809 /tmp/to/dst
3810 > cd ".."; echo $cwd
3811 /tmp/from
3812 > /bin/echo ..
3813 /tmp/to
3814 > /bin/echo ".."
3815 ..
3816 Note that `expand' expansion 1) works just like `ignore' for
3818 builtins like cd, 2) is prevented by quoting, and 3) happens
3819 before filenames are passed to non-builtin commands.
3820 tcsh (+)
3822 The version number of the shell in the format `R.VV.PP', where
3823 `R' is the major release number, `VV' the current version and
3824 `PP' the patchlevel.
3825 term The terminal type. Usually set in ~/.login as described under
3827 Startup and shutdown.
3828 time If set to a number, then the time builtin (q.v.) executes auto‐
3830 matically after each command which takes more than that many
3831 CPU seconds. If there is a second word, it is used as a format
3832 string for the output of the time builtin. (u) The following
3833 sequences may be used in the format string:
3834 %U The time the process spent in user mode in cpu seconds.
3836 %S The time the process spent in kernel mode in cpu seconds.
3837 %E The elapsed (wall clock) time in seconds.
3838 %P The CPU percentage computed as (%U + %S) / %E.
3839 %W Number of times the process was swapped.
3840 %X The average amount in (shared) text space used in Kbytes.
3841 %D The average amount in (unshared) data/stack space used in
3842 Kbytes.
3843 %K The total space used (%X + %D) in Kbytes.
3844 %M The maximum memory the process had in use at any time in
3845 Kbytes.
3846 %F The number of major page faults (page needed to be brought
3847 from disk).
3848 %R The number of minor page faults.
3849 %I The number of input operations.
3850 %O The number of output operations.
3851 %r The number of socket messages received.
3852 %s The number of socket messages sent.
3853 %k The number of signals received.
3854 %w The number of voluntary context switches (waits).
3855 %c The number of involuntary context switches.
3856 Only the first four sequences are supported on systems without
3858 BSD resource limit functions. The default time format is `%Uu
3859 %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
3860 resource usage reporting and `%Uu %Ss %E %P' for systems that
3861 do not.
3862 Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail‐
3864 able, but the following additional sequences are:
3865 %Y The number of system calls performed.
3867 %Z The number of pages which are zero-filled on demand.
3868 %i The number of times a process's resident set size was
3869 increased by the kernel.
3870 %d The number of times a process's resident set size was
3871 decreased by the kernel.
3872 %l The number of read system calls performed.
3873 %m The number of write system calls performed.
3874 %p The number of reads from raw disk devices.
3875 %q The number of writes to raw disk devices.
3876 and the default time format is `%Uu %Ss %E %P %I+%Oio
3878 %Fpf+%Ww'. Note that the CPU percentage can be higher than
3879 100% on multi-processors.
3880 tperiod (+)
3882 The period, in minutes, between executions of the periodic spe‐
3883 cial alias.
3884 tty (+) The name of the tty, or empty if not attached to one.
3886 uid (+) The user's real user ID.
3888 user The user's login name.
3890 verbose If set, causes the words of each command to be printed, after
3892 history substitution (if any). Set by the -v command line
3893 option.
3894 version (+)
3896 The version ID stamp. It contains the shell's version number
3897 (see tcsh), origin, release date, vendor, operating system and
3898 machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
3899 list of options which were set at compile time. Options which
3900 are set by default in the distribution are noted.
3901 8b The shell is eight bit clean; default
3903 7b The shell is not eight bit clean
3904 wide The shell is multibyte encoding clean (like UTF-8)
3905 nls The system's NLS is used; default for systems with NLS
3906 lf Login shells execute /etc/csh.login before instead of
3907 after /etc/csh.cshrc and ~/.login before instead of after
3908 ~/.tcshrc and ~/.history.
3909 dl `.' is put last in path for security; default
3910 nd `.' is omitted from path for security
3911 vi vi(1)-style editing is the default rather than
3912 emacs(1)-style
3913 dtr Login shells drop DTR when exiting
3914 bye bye is a synonym for logout and log is an alternate name
3915 for watchlog
3916 al autologout is enabled; default
3917 kan Kanji is used if appropriate according to locale set‐
3918 tings, unless the nokanji shell variable is set
3919 sm The system's malloc(3) is used
3920 hb The `#!<program> <args>' convention is emulated when exe‐
3921 cuting shell scripts
3922 ng The newgrp builtin is available
3923 rh The shell attempts to set the REMOTEHOST environment
3924 variable
3925 afs The shell verifies your password with the kerberos server
3926 if local authentication fails. The afsuser shell vari‐
3927 able or the AFSUSER environment variable override your
3928 local username if set.
3929 An administrator may enter additional strings to indicate dif‐
3931 ferences in the local version.
3932 vimode (+)
3934 If unset, various key bindings change behavior to be more
3935 emacs(1)-style: word boundaries are determined by wordchars
3936 versus other characters.
3937 If set, various key bindings change behavior to be more
3939 vi(1)-style: word boundaries are determined by wordchars versus
3940 whitespace versus other characters; cursor behavior depends
3941 upon current vi mode (command, delete, insert, replace).
3942 This variable is unset by bindkey -e and set by bindkey -v.
3944 vimode may be explicitly set or unset by the user after those
3945 bindkey operations if required.
3946 visiblebell (+)
3948 If set, a screen flash is used rather than the audible bell.
3949 See also nobeep.
3950 watch (+)
3952 A list of user/terminal pairs to watch for logins and logouts.
3953 If either the user is `any' all terminals are watched for the
3954 given user and vice versa. Setting watch to `(any any)'
3955 watches all users and terminals. For example,
3956 set watch = (george ttyd1 any console $user any)
3958 reports activity of the user `george' on ttyd1, any user on the
3960 console, and oneself (or a trespasser) on any terminal.
3961 Logins and logouts are checked every 10 minutes by default, but
3963 the first word of watch can be set to a number to check every
3964 so many minutes. For example,
3965 set watch = (1 any any)
3967 reports any login/logout once every minute. For the impatient,
3969 the log builtin command triggers a watch report at any time.
3970 All current logins are reported (as with the log builtin) when
3971 watch is first set.
3972 The who shell variable controls the format of watch reports.
3974 who (+) The format string for watch messages. The following sequences
3976 are replaced by the given information:
3977 %n The name of the user who logged in/out.
3979 %a The observed action, i.e., `logged on', `logged off' or
3980 `replaced olduser on'.
3981 %l The terminal (tty) on which the user logged in/out.
3982 %M The full hostname of the remote host, or `local' if the
3983 login/logout was from the local host.
3984 %m The hostname of the remote host up to the first `.'. The
3985 full name is printed if it is an IP address or an X Window
3986 System display.
3987 %M and %m are available on only systems that store the remote
3989 hostname in /etc/utmp. If unset, `%n has %a %l from %m.' is
3990 used, or `%n has %a %l.' on systems which don't store the
3991 remote hostname.
3992 wordchars (+)
3994 A list of non-alphanumeric characters to be considered part of
3995 a word by the forward-word, backward-word etc., editor com‐
3996 mands. If unset, the default value is determined based on the
3997 state of vimode: if vimode is unset, `*?_-.[]~=' is used as the
3998 default; if vimode is set, `_' is used as the default.
3999
4001 AFSUSER (+)
4002 Equivalent to the afsuser shell variable.
4003 COLUMNS The number of columns in the terminal. See Terminal manage‐
4005 ment.
4006 DISPLAY Used by X Window System (see X(1)). If set, the shell does not
4008 set autologout (q.v.).
4009 EDITOR The pathname to a default editor. Used by the run-fg-editor
4011 editor command if the the editors shell variable is unset. See
4012 also the VISUAL environment variable.
4013 GROUP (+)
4015 Equivalent to the group shell variable.
4016 HOME Equivalent to the home shell variable.
4018 HOST (+)
4020 Initialized to the name of the machine on which the shell is
4021 running, as determined by the gethostname(2) system call.
4022 HOSTTYPE (+)
4024 Initialized to the type of machine on which the shell is run‐
4025 ning, as determined at compile time. This variable is obsolete
4026 and will be removed in a future version.
4027 HPATH (+)
4029 A colon-separated list of directories in which the run-help
4030 editor command looks for command documentation.
4031 LANG Gives the preferred character environment. See Native Language
4033 System support.
4034 LC_CTYPE
4036 If set, only ctype character handling is changed. See Native
4037 Language System support.
4038 LINES The number of lines in the terminal. See Terminal management.
4040 LS_COLORS
4042 The format of this variable is reminiscent of the termcap(5)
4043 file format; a colon-separated list of expressions of the form
4044 "xx=string", where "xx" is a two-character variable name. The
4045 variables with their associated defaults are:
4046 no 0 Normal (non-filename) text
4048 fi 0 Regular file
4049 di 01;34 Directory
4050 ln 01;36 Symbolic link
4051 pi 33 Named pipe (FIFO)
4052 so 01;35 Socket
4053 do 01;35 Door
4054 bd 01;33 Block device
4055 cd 01;32 Character device
4056 ex 01;32 Executable file
4057 mi (none) Missing file (defaults to fi)
4058 or (none) Orphaned symbolic link (defaults to ln)
4059 lc ^[[ Left code
4060 rc m Right code
4061 ec (none) End code (replaces lc+no+rc)
4062 You need to include only the variables you want to change from
4064 the default.
4065 File names can also be colorized based on filename extension.
4067 This is specified in the LS_COLORS variable using the syntax
4068 "*ext=string". For example, using ISO 6429 codes, to color all
4069 C-language source files blue you would specify "*.c=34". This
4070 would color all files ending in .c in blue (34) color.
4071 Control characters can be written either in C-style-escaped
4073 notation, or in stty-like ^-notation. The C-style notation
4074 adds ^[ for Escape, _ for a normal space character, and ? for
4075 Delete. In addition, the ^[ escape character can be used to
4076 override the default interpretation of ^[, ^, : and =.
4077 Each file will be written as <lc> <color-code> <rc> <filename>
4079 <ec>. If the <ec> code is undefined, the sequence <lc> <no>
4080 <rc> will be used instead. This is generally more convenient
4081 to use, but less general. The left, right and end codes are
4082 provided so you don't have to type common parts over and over
4083 again and to support weird terminals; you will generally not
4084 need to change them at all unless your terminal does not use
4085 ISO 6429 color sequences but a different system.
4086 If your terminal does use ISO 6429 color codes, you can compose
4088 the type codes (i.e., all except the lc, rc, and ec codes) from
4089 numerical commands separated by semicolons. The most common
4090 commands are:
4091 0 to restore default color
4093 1 for brighter colors
4094 4 for underlined text
4095 5 for flashing text
4096 30 for black foreground
4097 31 for red foreground
4098 32 for green foreground
4099 33 for yellow (or brown) foreground
4100 34 for blue foreground
4101 35 for purple foreground
4102 36 for cyan foreground
4103 37 for white (or gray) foreground
4104 40 for black background
4105 41 for red background
4106 42 for green background
4107 43 for yellow (or brown) background
4108 44 for blue background
4109 45 for purple background
4110 46 for cyan background
4111 47 for white (or gray) background
4112 Not all commands will work on all systems or display devices.
4114 A few terminal programs do not recognize the default end code
4116 properly. If all text gets colorized after you do a directory
4117 listing, try changing the no and fi codes from 0 to the numeri‐
4118 cal codes for your standard fore- and background colors.
4119 MACHTYPE (+)
4121 The machine type (microprocessor class or machine model), as
4122 determined at compile time.
4123 NOREBIND (+)
4125 If set, printable characters are not rebound to self-insert-
4126 command. See Native Language System support.
4127 OSTYPE (+)
4129 The operating system, as determined at compile time.
4130 PATH A colon-separated list of directories in which to look for exe‐
4132 cutables. Equivalent to the path shell variable, but in a dif‐
4133 ferent format.
4134 PWD (+) Equivalent to the cwd shell variable, but not synchronized to
4136 it; updated only after an actual directory change.
4137 REMOTEHOST (+)
4139 The host from which the user has logged in remotely, if this is
4140 the case and the shell is able to determine it. Set only if
4141 the shell was so compiled; see the version shell variable.
4142 SHLVL (+)
4144 Equivalent to the shlvl shell variable.
4145 SYSTYPE (+)
4147 The current system type. (Domain/OS only)
4148 TERM Equivalent to the term shell variable.
4150 TERMCAP The terminal capability string. See Terminal management.
4152 USER Equivalent to the user shell variable.
4154 VENDOR (+)
4156 The vendor, as determined at compile time.
4157 VISUAL The pathname to a default full-screen editor. Used by the run-
4159 fg-editor editor command if the the editors shell variable is
4160 unset. See also the EDITOR environment variable.
4161
4163 /etc/csh.cshrc Read first by every shell. ConvexOS, Stellix and Intel
4164 use /etc/cshrc and NeXTs use /etc/cshrc.std. A/UX,
4165 AMIX, Cray and IRIX have no equivalent in csh(1), but
4166 read this file in tcsh anyway. Solaris 2.x does not
4167 have it either, but tcsh reads /etc/.cshrc. (+)
4168 /etc/csh.login Read by login shells after /etc/csh.cshrc. ConvexOS,
4169 Stellix and Intel use /etc/login, NeXTs use
4170 /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
4171 AMIX, Cray and IRIX use /etc/cshrc.
4172 ~/.tcshrc (+) Read by every shell after /etc/csh.cshrc or its equiva‐
4173 lent.
4174 ~/.cshrc Read by every shell, if ~/.tcshrc doesn't exist, after
4175 /etc/csh.cshrc or its equivalent. This manual uses
4176 `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
4177 found, ~/.cshrc'.
4178 ~/.history Read by login shells after ~/.tcshrc if savehist is
4179 set, but see also histfile.
4180 ~/.login Read by login shells after ~/.tcshrc or ~/.history.
4181 The shell may be compiled to read ~/.login before
4182 instead of after ~/.tcshrc and ~/.history; see the ver‐
4183 sion shell variable.
4184 ~/.cshdirs (+) Read by login shells after ~/.login if savedirs is set,
4185 but see also dirsfile.
4186 /etc/csh.logout Read by login shells at logout. ConvexOS, Stellix and
4187 Intel use /etc/logout and NeXTs use /etc/logout.std.
4188 A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
4189 but read this file in tcsh anyway. Solaris 2.x does
4190 not have it either, but tcsh reads /etc/.logout. (+)
4191 ~/.logout Read by login shells at logout after /etc/csh.logout or
4192 its equivalent.
4193 /bin/sh Used to interpret shell scripts not starting with a
4194 `#'.
4195 /tmp/sh* Temporary file for `<<'.
4196 /etc/passwd Source of home directories for `~name' substitutions.
4197 The order in which startup files are read may differ if the shell was
4199 so compiled; see Startup and shutdown and the version shell variable.
4200
4202 This manual describes tcsh as a single entity, but experienced csh(1)
4203 users will want to pay special attention to tcsh's new features.
4204 A command-line editor, which supports emacs(1)-style or vi(1)-style key
4206 bindings. See The command-line editor and Editor commands.
4207 Programmable, interactive word completion and listing. See Completion
4209 and listing and the complete and uncomplete builtin commands.
4210 Spelling correction (q.v.) of filenames, commands and variables.
4212 Editor commands (q.v.) which perform other useful functions in the mid‐
4214 dle of typed commands, including documentation lookup (run-help), quick
4215 editor restarting (run-fg-editor) and command resolution (which-com‐
4216 mand).
4217 An enhanced history mechanism. Events in the history list are time-
4219 stamped. See also the history command and its associated shell vari‐
4220 ables, the previously undocumented `#' event specifier and new modi‐
4221 fiers under History substitution, the *-history, history-search-*, i-
4222 search-*, vi-search-* and toggle-literal-history editor commands and
4223 the histlit shell variable.
4224 Enhanced directory parsing and directory stack handling. See the cd,
4226 pushd, popd and dirs commands and their associated shell variables, the
4227 description of Directory stack substitution, the dirstack, owd and sym‐
4228 links shell variables and the normalize-command and normalize-path edi‐
4229 tor commands.
4230 Negation in glob-patterns. See Filename substitution.
4232 New File inquiry operators (q.v.) and a filetest builtin which uses
4234 them.
4235 A variety of Automatic, periodic and timed events (q.v.) including
4237 scheduled events, special aliases, automatic logout and terminal lock‐
4238 ing, command timing and watching for logins and logouts.
4239 Support for the Native Language System (see Native Language System sup‐
4241 port), OS variant features (see OS variant support and the echo_style
4242 shell variable) and system-dependent file locations (see FILES).
4243 Extensive terminal-management capabilities. See Terminal management.
4245 New builtin commands including builtins, hup, ls-F, newgrp, printenv,
4247 which and where (q.v.).
4248 New variables that make useful information easily available to the
4250 shell. See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version
4251 shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
4252 environment variables.
4253 A new syntax for including useful information in the prompt string (see
4255 prompt), and special prompts for loops and spelling correction (see
4256 prompt2 and prompt3).
4257 Read-only variables. See Variable substitution.
4259
4261 When a suspended command is restarted, the shell prints the directory
4262 it started in if this is different from the current directory. This
4263 can be misleading (i.e., wrong) as the job may have changed directories
4264 internally.
4265 Shell builtin functions are not stoppable/restartable. Command
4267 sequences of the form `a ; b ; c' are also not handled gracefully when
4268 stopping is attempted. If you suspend `b', the shell will then immedi‐
4269 ately execute `c'. This is especially noticeable if this expansion
4270 results from an alias. It suffices to place the sequence of commands
4271 in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.
4272 Control over tty output after processes are started is primitive; per‐
4274 haps this will inspire someone to work on a good virtual terminal
4275 interface. In a virtual terminal interface much more interesting
4276 things could be done with output control.
4277 Alias substitution is most often used to clumsily simulate shell proce‐
4279 dures; shell procedures should be provided rather than aliases.
4280 Control structures should be parsed rather than being recognized as
4282 built-in commands. This would allow control commands to be placed any‐
4283 where, to be combined with `|', and to be used with `&' and `;' meta‐
4284 syntax.
4285 foreach doesn't ignore here documents when looking for its end.
4287 It should be possible to use the `:' modifiers on the output of command
4289 substitutions.
4290 The screen update for lines longer than the screen width is very poor
4292 if the terminal cannot move the cursor up (i.e., terminal type `dumb').
4293 HPATH and NOREBIND don't need to be environment variables.
4295 Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
4297 `~' are not negated correctly.
4298 The single-command form of if does output redirection even if the
4300 expression is false and the command is not executed.
4301 ls-F includes file identification characters when sorting filenames and
4303 does not handle control characters in filenames well. It cannot be
4304 interrupted.
4305 Command substitution supports multiple commands and conditions, but not
4307 cycles or backward gotos.
4308 Report bugs at https://bugs.astron.com/, preferably with fixes. If you
4310 want to help maintain and test tcsh, add yourself to the mailing list
4311 in https://mailman.astron.com/.
4312
4314 In 1964, DEC produced the PDP-6. The PDP-10 was a later re-implementa‐
4315 tion. It was re-christened the DECsystem-10 in 1970 or so when DEC
4316 brought out the second model, the KI10.
4317 TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
4319 think tank) in 1972 as an experiment in demand-paged virtual memory
4320 operating systems. They built a new pager for the DEC PDP-10 and cre‐
4321 ated the OS to go with it. It was extremely successful in academia.
4322 In 1975, DEC brought out a new model of the PDP-10, the KL10; they
4324 intended to have only a version of TENEX, which they had licensed from
4325 BBN, for the new box. They called their version TOPS-20 (their capi‐
4326 talization is trademarked). A lot of TOPS-10 users (`The OPerating
4327 System for PDP-10') objected; thus DEC found themselves supporting two
4328 incompatible systems on the same hardware--but then there were 6 on the
4329 PDP-11!
4330 TENEX, and TOPS-20 to version 3, had command completion via a user-
4332 code-level subroutine library called ULTCMD. With version 3, DEC moved
4333 all that capability and more into the monitor (`kernel' for you Unix
4334 types), accessed by the COMND% JSYS (`Jump to SYStem' instruction, the
4335 supervisor call mechanism [are my IBM roots also showing?]).
4336 The creator of tcsh was impressed by this feature and several others of
4338 TENEX and TOPS-20, and created a version of csh which mimicked them.
4339
4341 The system limits argument lists to ARG_MAX characters.
4342 The number of arguments to a command which involves filename expansion
4344 is limited to 1/6th the number of characters allowed in an argument
4345 list.
4346 Command substitutions may substitute no more characters than are
4348 allowed in an argument list.
4349 To detect looping, the shell restricts the number of alias substitu‐
4351 tions on a single line to 20.
4352
4354 csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
4355 tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
4356 pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
4357 malloc(3), setlocale(3), tty(4), a.out(5), termcap(5), environ(7),
4358 termio(7), Introduction to the C Shell
4359
4361 This manual documents tcsh 6.22.03 (Astron) 2020-11-18.
4362
4364 William Joy
4365 Original author of csh(1)
4366 J.E. Kulp, IIASA, Laxenburg, Austria
4367 Job control and directory stack features
4368 Ken Greer, HP Labs, 1981
4369 File name completion
4370 Mike Ellis, Fairchild, 1983
4371 Command name recognition/completion
4372 Paul Placeway, Ohio State CIS Dept., 1983-1993
4373 Command line editor, prompt routines, new glob syntax and numerous
4374 fixes and speedups
4375 Karl Kleinpaste, CCI 1983-4
4376 Special aliases, directory stack extraction stuff, login/logout
4377 watch, scheduled events, and the idea of the new prompt format
4378 Rayan Zachariassen, University of Toronto, 1984
4379 ls-F and which builtins and numerous bug fixes, modifications and
4380 speedups
4381 Chris Kingsley, Caltech
4382 Fast storage allocator routines
4383 Chris Grevstad, TRW, 1987
4384 Incorporated 4.3BSD csh into tcsh
4385 Christos S. Zoulas, Cornell U. EE Dept., 1987-94
4386 Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
4387 SHORT_STRINGS support and a new version of sh.glob.c
4388 James J Dempsey, BBN, and Paul Placeway, OSU, 1988
4389 A/UX port
4390 Daniel Long, NNSC, 1988
4391 wordchars
4392 Patrick Wolfe, Kuck and Associates, Inc., 1988
4393 vi mode cleanup
4394 David C Lawrence, Rensselaer Polytechnic Institute, 1989
4395 autolist and ambiguous completion listing
4396 Alec Wolman, DEC, 1989
4397 Newlines in the prompt
4398 Matt Landau, BBN, 1989
4399 ~/.tcshrc
4400 Ray Moody, Purdue Physics, 1989
4401 Magic space bar history expansion
4402 Mordechai ????, Intel, 1989
4403 printprompt() fixes and additions
4404 Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
4405 Automatic spelling correction and prompt3
4406 Per Hedeland, Ellemtel, Sweden, 1990-
4407 Various bugfixes, improvements and manual updates
4408 Hans J. Albertsson (Sun Sweden)
4409 ampm, settc and telltc
4410 Michael Bloom
4411 Interrupt handling fixes
4412 Michael Fine, Digital Equipment Corp
4413 Extended key support
4414 Eric Schnoebelen, Convex, 1990
4415 Convex support, lots of csh bug fixes, save and restore of directory
4416 stack
4417 Ron Flax, Apple, 1990
4418 A/UX 2.0 (re)port
4419 Dan Oscarsson, LTH Sweden, 1990
4420 NLS support and simulated NLS support for non NLS sites, fixes
4421 Johan Widen, SICS Sweden, 1990
4422 shlvl, Mach support, correct-line, 8-bit printing
4423 Matt Day, Sanyo Icon, 1990
4424 POSIX termio support, SysV limit fixes
4425 Jaap Vermeulen, Sequent, 1990-91
4426 Vi mode fixes, expand-line, window change fixes, Symmetry port
4427 Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
4428 autolist beeping options, modified the history search to search for
4429 the whole string from the beginning of the line to the cursor.
4430 Scott Krotz, Motorola, 1991
4431 Minix port
4432 David Dawes, Sydney U. Australia, Physics Dept., 1991
4433 SVR4 job control fixes
4434 Jose Sousa, Interactive Systems Corp., 1991
4435 Extended vi fixes and vi delete command
4436 Marc Horowitz, MIT, 1991
4437 ANSIfication fixes, new exec hashing code, imake fixes, where
4438 Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
4439 ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
4440 and various other portability changes and bug fixes
4441 Jeff Fink, 1992
4442 complete-word-fwd and complete-word-back
4443 Harry C. Pulley, 1992
4444 Coherent port
4445 Andy Phillips, Mullard Space Science Lab U.K., 1992
4446 VMS-POSIX port
4447 Beto Appleton, IBM Corp., 1992
4448 Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
4449 SIGHUP
4450 Scott Bolte, Cray Computer Corp., 1992
4451 CSOS port
4452 Kaveh R. Ghazi, Rutgers University, 1992
4453 Tek, m88k, Titan and Masscomp ports and fixes. Added autoconf sup‐
4454 port.
4455 Mark Linderman, Cornell University, 1992
4456 OS/2 port
4457 Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
4458 Linux port
4459 Tim P. Starrin, NASA Langley Research Center Operations, 1993
4460 Read-only variables
4461 Dave Schweisguth, Yale University, 1993-4
4462 New man page and tcsh.man2html
4463 Larry Schwimmer, Stanford University, 1993
4464 AFS and HESIOD patches
4465 Luke Mewburn, RMIT University, 1994-6
4466 Enhanced directory printing in prompt, added ellipsis and rprompt.
4467 Edward Hutchins, Silicon Graphics Inc., 1996
4468 Added implicit cd.
4469 Martin Kraemer, 1997
4470 Ported to Siemens Nixdorf EBCDIC machine
4471 Amol Deshpande, Microsoft, 1997
4472 Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
4473 library and message catalog code to interface to Windows.
4474 Taga Nayuta, 1998
4475 Color ls additions.
4476
4478 Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
4479 Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
4480 the other people at Ohio State for suggestions and encouragement
4481 All the people on the net, for putting up with, reporting bugs in, and
4483 suggesting new additions to each and every version
4484 Richard M. Alderson III, for writing the `T in tcsh' section
4486Astron 6.22.03 11 Nov 2020 TCSH(1)