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 lo‐
28 gin 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 ~/.tc‐
114 shrc is not found, ~/.cshrc, then the contents of ~/.history (or the
115 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 af‐
118 ter /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 lo‐
129 gin, usually go in one's ~/.login file. Users who need to use the same
130 set of files with both csh(1) and tcsh can have only a ~/.cshrc which
131 checks for the existence of the tcsh shell variable (q.v.) before using
132 tcsh-specific commands, or can have both a ~/.cshrc and a ~/.tcshrc
133 which sources (see the builtin command) ~/.cshrc. The rest of this
134 manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
135 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 lo‐
149 gout 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 ex‐
217 ample, 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 re‐
276 lated 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 ig‐
286 nored 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), be‐
299 cause 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 un‐
301 der Filename substitution. fignore is ignored if only one completion
302 is possible.
303 If the complete shell variable is set to `enhance', completion 1) ig‐
305 nores case and 2) considers periods, hyphens and underscores (`.', `-'
306 and `_') to be word separators and hyphens and underscores to be equiv‐
307 alent. 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 un‐
320 derscores are equivalent. Periods, however, are not equivalent to hy‐
321 phens 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 de‐
408 scribes 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 vi‐
506 mode.
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 vi‐
527 mode.
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 be‐
535 ginning with the current contents of the input buffer up to the
536 cursor and copies it into the input buffer. The search string
537 may be a glob-pattern (see Filename substitution) containing
538 `*', `?', `[]' or `{}'. up-history and down-history will pro‐
539 ceed from the appropriate point in the history list. Emacs
540 mode only. See also history-search-forward and i-search-back.
541 history-search-forward (M-n, M-N)
543 Like history-search-backward, but searches forward.
544 i-search-back (not bound)
546 Searches backward like history-search-backward, copies the
547 first match into the input buffer with the cursor positioned at
548 the end of the pattern, and prompts with `bck: ' and the first
549 match. Additional characters may be typed to extend the
550 search, i-search-back may be typed to continue searching with
551 the same pattern, wrapping around the history list if neces‐
552 sary, (i-search-back must be bound to a single character for
553 this to work) or one of the following special characters may be
554 typed:
555 ^W Appends the rest of the word under the cursor to
557 the search pattern.
558 delete (or any character bound to backward-delete-char)
559 Undoes the effect of the last character typed and
560 deletes a character from the search pattern if ap‐
561 propriate.
562 ^G If the previous search was successful, aborts the
563 entire search. If not, goes back to the last suc‐
564 cessful search.
565 escape Ends the search, leaving the current line in the
566 input buffer.
567 Any other character not bound to self-insert-command terminates
569 the search, leaving the current line in the input buffer, and
570 is then interpreted as normal input. In particular, a carriage
571 return causes the current line to be executed. See also i-
572 search-fwd and history-search-backward. Word boundary behavior
573 modified by vimode.
574 i-search-fwd (not bound)
576 Like i-search-back, but searches forward. Word boundary behav‐
577 ior modified by vimode.
578 insert-last-word (M-_)
580 Inserts the last word of the previous input line (`!$') into
581 the input buffer. See also copy-prev-word.
582 list-choices (M-^D)
584 Lists completion possibilities as described under Completion
585 and listing. See also delete-char-or-list-or-eof and list-
586 choices-raw.
587 list-choices-raw (^X-^D)
589 Like list-choices, but ignores user-defined completions.
590 list-glob (^X-g, ^X-G)
592 Lists (via the ls-F builtin) matches to the glob-pattern (see
593 Filename substitution) to the left of the cursor.
594 list-or-eof (not bound)
596 Does list-choices or end-of-file on an empty line. See also
597 delete-char-or-list-or-eof.
598 magic-space (not bound)
600 Expands history substitutions in the current line, like expand-
601 history, and inserts a space. magic-space is designed to be
602 bound to the space bar, but is not bound by default.
603 normalize-command (^X-?)
605 Searches for the current word in PATH and, if it is found, re‐
606 places it with the full path to the executable. Special char‐
607 acters are quoted. Aliases are expanded and quoted but com‐
608 mands within aliases are not. This command is useful with com‐
609 mands that take commands as arguments, e.g., `dbx' and `sh -x'.
610 normalize-path (^X-n, ^X-N)
612 Expands the current word as described under the `expand' set‐
613 ting of the symlinks shell variable.
614 overwrite-mode (unbound)
616 Toggles between input and overwrite modes.
617 run-fg-editor (M-^Z)
619 Saves the current input line and looks for a stopped job where
620 the file name portion of its first word is found in the editors
621 shell variable. If editors is not set, then the file name por‐
622 tion of the EDITOR environment variable (`ed' if unset) and the
623 VISUAL environment variable (`vi' if unset) will be used. If
624 such a job is found, it is restarted as if `fg %job' had been
625 typed. This is used to toggle back and forth between an editor
626 and the shell easily. Some people bind this command to `^Z' so
627 they can do this even more easily.
628 run-help (M-h, M-H)
630 Searches for documentation on the current command, using the
631 same notion of `current command' as the completion routines,
632 and prints it. There is no way to use a pager; run-help is de‐
633 signed for short help files. If the special alias helpcommand
634 is defined, it is run with the command name as a sole argument.
635 Else, documentation should be in a file named command.help,
636 command.1, command.6, command.8 or command, which should be in
637 one of the directories listed in the HPATH environment vari‐
638 able. If there is more than one help file only the first is
639 printed.
640 self-insert-command (text characters)
642 In insert mode (the default), inserts the typed character into
643 the input line after the character under the cursor. In over‐
644 write mode, replaces the character under the cursor with the
645 typed character. The input mode is normally preserved between
646 lines, but the inputmode shell variable can be set to `insert'
647 or `overwrite' to put the editor in that mode at the beginning
648 of each line. See also overwrite-mode.
649 sequence-lead-in (arrow prefix, meta prefix, ^X)
651 Indicates that the following characters are part of a multi-key
652 sequence. Binding a command to a multi-key sequence really
653 creates two bindings: the first character to sequence-lead-in
654 and the whole sequence to the command. All sequences beginning
655 with a character bound to sequence-lead-in are effectively
656 bound to undefined-key unless bound to another command.
657 spell-line (M-$)
659 Attempts to correct the spelling of each word in the input buf‐
660 fer, like spell-word, but ignores words whose first character
661 is one of `-', `!', `^' or `%', or which contain `\', `*' or
662 `?', to avoid problems with switches, substitutions and the
663 like. See Spelling correction.
664 spell-word (M-s, M-S)
666 Attempts to correct the spelling of the current word as de‐
667 scribed under Spelling correction. Checks each component of a
668 word which appears to be a pathname.
669 toggle-literal-history (M-r, M-R)
671 Expands or `unexpands' history substitutions in the input buf‐
672 fer. See also expand-history and the autoexpand shell vari‐
673 able.
674 undefined-key (any unbound key)
676 Beeps.
677 up-history (up-arrow, ^P)
679 Copies the previous entry in the history list into the input
680 buffer. If histlit is set, uses the literal form of the entry.
681 May be repeated to step up through the history list, stopping
682 at the top.
683 upcase-word (M-u, M-U)
685 Uppercase the characters from cursor to end of current word.
686 Word boundary behavior modified by vimode.
687 vi-beginning-of-next-word (not bound)
689 Vi goto the beginning of next word. Word boundary and cursor
690 behavior modified by vimode.
691 vi-eword (not bound)
693 Vi move to the end of the current word. Word boundary behavior
694 modified by vimode.
695 vi-search-back (?)
697 Prompts with `?' for a search string (which may be a glob-pat‐
698 tern, as with history-search-backward), searches for it and
699 copies it into the input buffer. The bell rings if no match is
700 found. Hitting return ends the search and leaves the last
701 match in the input buffer. Hitting escape ends the search and
702 executes the match. vi mode only.
703 vi-search-fwd (/)
705 Like vi-search-back, but searches forward.
706 which-command (M-?)
708 Does a which (see the description of the builtin command) on
709 the first word of the input buffer.
710 yank-pop (M-y)
712 When executed immediately after a yank or another yank-pop, re‐
713 places the yanked string with the next previous string from the
714 killring. This also has the effect of rotating the killring,
715 such that this string will be considered the most recently
716 killed by a later yank command. Repeating yank-pop will cycle
717 through the killring any number of times.
718 Lexical structure
720 The shell splits input lines into words at blanks and tabs. The spe‐
721 cial characters `&', `|', `;', `<', `>', `(', and `)' and the doubled
722 characters `&&', `||', `<<' and `>>' are always separate words, whether
723 or not they are surrounded by whitespace.
724 When the shell's input is not a terminal, the character `#' is taken to
726 begin a comment. Each `#' and the rest of the input line on which it
727 appears is discarded before further parsing.
728 A special character (including a blank or tab) may be prevented from
730 having its special meaning, and possibly made part of another word, by
731 preceding it with a backslash (`\') or enclosing it in single (`''),
732 double (`"') or backward (``') quotes. When not otherwise quoted a
733 newline preceded by a `\' is equivalent to a blank, but inside quotes
734 this sequence results in a newline.
735 Furthermore, all Substitutions (see below) except History substitution
737 can be prevented by enclosing the strings (or parts of strings) in
738 which they appear with single quotes or by quoting the crucial charac‐
739 ter(s) (e.g., `$' or ``' for Variable substitution or Command substitu‐
740 tion respectively) with `\'. (Alias substitution is no exception:
741 quoting in any way any character of a word for which an alias has been
742 defined prevents substitution of the alias. The usual way of quoting
743 an alias is to precede it with a backslash.) History substitution is
744 prevented by backslashes but not by single quotes. Strings quoted with
745 double or backward quotes undergo Variable substitution and Command
746 substitution, but other substitutions are prevented.
747 Text inside single or double quotes becomes a single word (or part of
749 one). Metacharacters in these strings, including blanks and tabs, do
750 not form separate words. Only in one special case (see Command substi‐
751 tution below) can a double-quoted string yield parts of more than one
752 word; single-quoted strings never do. Backward quotes are special:
753 they signal Command substitution (q.v.), which may result in more than
754 one word.
755 Quoting complex strings, particularly strings which themselves contain
757 quoting characters, can be confusing. Remember that quotes need not be
758 used as they are in human writing! It may be easier to quote not an
759 entire string, but only those parts of the string which need quoting,
760 using different types of quoting to do so if appropriate.
761 The backslash_quote shell variable (q.v.) can be set to make back‐
763 slashes always quote `\', `'', and `"'. (+) This may make complex
764 quoting tasks easier, but it can cause syntax errors in csh(1) scripts.
765 Substitutions
767 We now describe the various transformations the shell performs on the
768 input in the order in which they occur. We note in passing the data
769 structures involved and the commands and variables which affect them.
770 Remember that substitutions can be prevented by quoting as described
771 under Lexical structure.
772 History substitution
774 Each command, or ``event'', input from the terminal is saved in the
775 history list. The previous command is always saved, and the history
776 shell variable can be set to a number to save that many commands. The
777 histdup shell variable can be set to not save duplicate events or con‐
778 secutive duplicate events.
779 Saved commands are numbered sequentially from 1 and stamped with the
781 time. It is not usually necessary to use event numbers, but the cur‐
782 rent event number can be made part of the prompt by placing an `!' in
783 the prompt shell variable.
784 By default history entries are displayed by printing each parsed token
786 separated by space; thus the redirection operator `>&!' will be dis‐
787 played as `> & !'.
788 The shell actually saves history in expanded and literal (unexpanded)
790 forms. If the histlit shell variable is set, commands that display and
791 store history use the literal form.
792 The history builtin command can print, store in a file, restore and
794 clear the history list at any time, and the savehist and histfile shell
795 variables can be set to store the history list automatically on logout
796 and restore it on login.
797 History substitutions introduce words from the history list into the
799 input stream, making it easy to repeat commands, repeat arguments of a
800 previous command in the current command, or fix spelling mistakes in
801 the previous command with little typing and a high degree of confi‐
802 dence.
803 History substitutions begin with the character `!'. They may begin
805 anywhere in the input stream, but they do not nest. The `!' may be
806 preceded by a `\' to prevent its special meaning; for convenience, a
807 `!' is passed unchanged when it is followed by a blank, tab, newline,
808 `=' or `('. History substitutions also occur when an input line begins
809 with `^'. This special abbreviation will be described later. The
810 characters used to signal history substitution (`!' and `^') can be
811 changed by setting the histchars shell variable. Any input line which
812 contains a history substitution is printed before it is executed.
813 A history substitution may have an ``event specification'', which indi‐
815 cates the event from which words are to be taken, a ``word designa‐
816 tor'', which selects particular words from the chosen event, and/or a
817 ``modifier'', which manipulates the selected words.
818 An event specification can be
820 n A number, referring to a particular event
822 -n An offset, referring to the event n before the current
823 event
824 # The current event. This should be used carefully in
825 csh(1), where there is no check for recursion. tcsh allows
826 10 levels of recursion. (+)
827 ! The previous event (equivalent to `-1')
828 s The most recent event whose first word begins with the
829 string s
830 ?s? The most recent event which contains the string s. The
831 second `?' can be omitted if it is immediately followed by
832 a newline.
833 For example, consider this bit of someone's history list:
835 9 8:30 nroff -man wumpus.man
837 10 8:31 cp wumpus.man wumpus.man.old
838 11 8:36 vi wumpus.man
839 12 8:37 diff wumpus.man.old wumpus.man
840 The commands are shown with their event numbers and time stamps. The
842 current event, which we haven't typed in yet, is event 13. `!11' and
843 `!-2' refer to event 11. `!!' refers to the previous event, 12. `!!'
844 can be abbreviated `!' if it is followed by `:' (`:' is described be‐
845 low). `!n' refers to event 9, which begins with `n'. `!?old?' also
846 refers to event 12, which contains `old'. Without word designators or
847 modifiers history references simply expand to the entire event, so we
848 might type `!cp' to redo the copy command or `!!|more' if the `diff'
849 output scrolled off the top of the screen.
850 History references may be insulated from the surrounding text with
852 braces if necessary. For example, `!vdoc' would look for a command be‐
853 ginning with `vdoc', and, in this example, not find one, but `!{v}doc'
854 would expand unambiguously to `vi wumpus.mandoc'. Even in braces, his‐
855 tory substitutions do not nest.
856 (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
858 `d' appended to it, tcsh expands it to the last event beginning with
859 `3d'; only completely numeric arguments are treated as event numbers.
860 This makes it possible to recall events beginning with numbers. To ex‐
861 pand `!3d' as in csh(1) say `!{3}d'.
862 To select words from an event we can follow the event specification by
864 a `:' and a designator for the desired words. The words of an input
865 line are numbered from 0, the first (usually command) word being 0, the
866 second word (first argument) being 1, etc. The basic word designators
867 are:
868 0 The first (command) word
870 n The nth argument
871 ^ The first argument, equivalent to `1'
872 $ The last argument
873 % The word matched by an ?s? search
874 x-y A range of words
875 -y Equivalent to `0-y'
876 * Equivalent to `^-$', but returns nothing if the event con‐
877 tains only 1 word
878 x* Equivalent to `x-$'
879 x- Equivalent to `x*', but omitting the last word (`$')
880 Selected words are inserted into the command line separated by single
882 blanks. For example, the `diff' command in the previous example might
883 have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
884 argument from the previous event) or `diff !-2:2 !-2:1' to select and
885 swap the arguments from the `cp' command. If we didn't care about the
886 order of the `diff' we might have said `diff !-2:1-2' or simply `diff
887 !-2:*'. The `cp' command might have been written `cp wumpus.man
888 !#:1.old', using `#' to refer to the current event. `!n:- hurkle.man'
889 would reuse the first two words from the `nroff' command to say `nroff
890 -man hurkle.man'.
891 The `:' separating the event specification from the word designator can
893 be omitted if the argument selector begins with a `^', `$', `*', `%' or
894 `-'. For example, our `diff' command might have been `diff !!^.old
895 !!^' or, equivalently, `diff !!$.old !!$'. However, if `!!' is abbre‐
896 viated `!', an argument selector beginning with `-' will be interpreted
897 as an event specification.
898 A history reference may have a word designator but no event specifica‐
900 tion. It then references the previous command. Continuing our `diff'
901 example, we could have said simply `diff !^.old !^' or, to get the ar‐
902 guments in the opposite order, just `diff !*'.
903 The word or words in a history reference can be edited, or ``modi‐
905 fied'', by following it with one or more modifiers, each preceded by a
906 `:':
907 h Remove a trailing pathname component, leaving the head.
909 t Remove all leading pathname components, leaving the tail.
910 r Remove a filename extension `.xxx', leaving the root name.
911 e Remove all but the extension.
912 u Uppercase the first lowercase letter.
913 l Lowercase the first uppercase letter.
914 s/l/r/ Substitute l for r. l is simply a string like r, not a
915 regular expression as in the eponymous ed(1) command. Any
916 character may be used as the delimiter in place of `/'; a
917 `\' can be used to quote the delimiter inside l and r. The
918 character `&' in the r is replaced by l; `\' also quotes
919 `&'. If l is empty (``''), the l from a previous substitu‐
920 tion or the s from a previous search or event number in
921 event specification is used. The trailing delimiter may be
922 omitted if it is immediately followed by a newline.
923 & Repeat the previous substitution.
924 g Apply the following modifier once to each word.
925 a (+) Apply the following modifier as many times as possible to a
926 single word. `a' and `g' can be used together to apply a
927 modifier globally. With the `s' modifier, only the pat‐
928 terns contained in the original word are substituted, not
929 patterns that contain any substitution result.
930 p Print the new command line but do not execute it.
931 q Quote the substituted words, preventing further substitu‐
932 tions.
933 Q Same as q but in addition preserve empty variables as a
934 string containing a NUL. This is useful to preserve posi‐
935 tional arguments for example:
936 > set args=('arg 1' '' 'arg 3')
937 > tcsh -f -c 'echo ${#argv}' $args:gQ
938 3
939 x Like q, but break into words at blanks, tabs and newlines.
940 Modifiers are applied to only the first modifiable word (unless `g' is
942 used). It is an error for no word to be modifiable.
943 For example, the `diff' command might have been written as `diff wum‐
945 pus.man.old !#^:r', using `:r' to remove `.old' from the first argument
946 on the same line (`!#^'). We could say `echo hello out there', then
947 `echo !*:u' to capitalize `hello', `echo !*:au' to say it out loud, or
948 `echo !*:agu' to really shout. We might follow `mail -s "I forgot my
949 password" rot' with `!:s/rot/root' to correct the spelling of `root'
950 (but see Spelling correction for a different approach).
951 There is a special abbreviation for substitutions. `^', when it is the
953 first character on an input line, is equivalent to `!:s^'. Thus we
954 might have said `^rot^root' to make the spelling correction in the pre‐
955 vious example. This is the only history substitution which does not
956 explicitly begin with `!'.
957 (+) In csh as such, only one modifier may be applied to each history or
959 variable expansion. In tcsh, more than one may be used, for example
960 % mv wumpus.man /usr/man/man1/wumpus.1
962 % man !$:t:r
963 man wumpus
964 In csh, the result would be `wumpus.1:r'. A substitution followed by a
966 colon may need to be insulated from it with braces:
967 > mv a.out /usr/games/wumpus
969 > setenv PATH !$:h:$PATH
970 Bad ! modifier: $.
971 > setenv PATH !{-2$:h}:$PATH
972 setenv PATH /usr/games:/bin:/usr/bin:.
973 The first attempt would succeed in csh but fails in tcsh, because tcsh
975 expects another modifier after the second colon rather than `$'.
976 Finally, history can be accessed through the editor as well as through
978 the substitutions just described. The up- and down-history, history-
979 search-backward and -forward, i-search-back and -fwd, vi-search-back
980 and -fwd, copy-prev-word and insert-last-word editor commands search
981 for events in the history list and copy them into the input buffer.
982 The toggle-literal-history editor command switches between the expanded
983 and literal forms of history lines in the input buffer. expand-history
984 and expand-line expand history substitutions in the current word and in
985 the entire input buffer respectively.
986 Alias substitution
988 The shell maintains a list of aliases which can be set, unset and
989 printed by the alias and unalias commands. After a command line is
990 parsed into simple commands (see Commands) the first word of each com‐
991 mand, left-to-right, is checked to see if it has an alias. If so, the
992 first word is replaced by the alias. If the alias contains a history
993 reference, it undergoes History substitution (q.v.) as though the orig‐
994 inal command were the previous input line. If the alias does not con‐
995 tain a history reference, the argument list is left untouched.
996 Thus if the alias for `ls' were `ls -l' the command `ls /usr' would be‐
998 come `ls -l /usr', the argument list here being undisturbed. If the
999 alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
1000 become `grep bill /etc/passwd'. Aliases can be used to introduce
1001 parser metasyntax. For example, `alias print 'pr \!* | lpr'' defines a
1002 ``command'' (`print') which pr(1)s its arguments to the line printer.
1003 Alias substitution is repeated until the first word of the command has
1005 no alias. If an alias substitution does not change the first word (as
1006 in the previous example) it is flagged to prevent a loop. Other loops
1007 are detected and cause an error.
1008 Some aliases are referred to by the shell; see Special aliases.
1010 Variable substitution
1012 The shell maintains a list of variables, each of which has as value a
1013 list of zero or more words. The values of shell variables can be dis‐
1014 played and changed with the set and unset commands. The system main‐
1015 tains its own list of ``environment'' variables. These can be dis‐
1016 played and changed with printenv, setenv and unsetenv.
1017 (+) Variables may be made read-only with `set -r' (q.v.). Read-only
1019 variables may not be modified or unset; attempting to do so will cause
1020 an error. Once made read-only, a variable cannot be made writable, so
1021 `set -r' should be used with caution. Environment variables cannot be
1022 made read-only.
1023 Some variables are set by the shell or referred to by it. For in‐
1025 stance, the argv variable is an image of the shell's argument list, and
1026 words of this variable's value are referred to in special ways. Some
1027 of the variables referred to by the shell are toggles; the shell does
1028 not care what their value is, only whether they are set or not. For
1029 instance, the verbose variable is a toggle which causes command input
1030 to be echoed. The -v command line option sets this variable. Special
1031 shell variables lists all variables which are referred to by the shell.
1032 Other operations treat variables numerically. The `@' command permits
1034 numeric calculations to be performed and the result assigned to a vari‐
1035 able. Variable values are, however, always represented as (zero or
1036 more) strings. For the purposes of numeric operations, the null string
1037 is considered to be zero, and the second and subsequent words of multi-
1038 word values are ignored.
1039 After the input line is aliased and parsed, and before each command is
1041 executed, variable substitution is performed keyed by `$' characters.
1042 This expansion can be prevented by preceding the `$' with a `\' except
1043 within `"'s where it always occurs, and within `''s where it never oc‐
1044 curs. Strings quoted by ``' are interpreted later (see Command substi‐
1045 tution below) so `$' substitution does not occur there until later, if
1046 at all. A `$' is passed unchanged if followed by a blank, tab, or end-
1047 of-line.
1048 Input/output redirections are recognized before variable expansion, and
1050 are variable expanded separately. Otherwise, the command name and en‐
1051 tire argument list are expanded together. It is thus possible for the
1052 first (command) word (to this point) to generate more than one word,
1053 the first of which becomes the command name, and the rest of which be‐
1054 come arguments.
1055 Unless enclosed in `"' or given the `:q' modifier the results of vari‐
1057 able substitution may eventually be command and filename substituted.
1058 Within `"', a variable whose value consists of multiple words expands
1059 to a (portion of a) single word, with the words of the variable's value
1060 separated by blanks. When the `:q' modifier is applied to a substitu‐
1061 tion the variable will expand to multiple words with each word sepa‐
1062 rated by a blank and quoted to prevent later command or filename sub‐
1063 stitution.
1064 The following metasequences are provided for introducing variable val‐
1066 ues into the shell input. Except as noted, it is an error to reference
1067 a variable which is not set.
1068 $name
1070 ${name} Substitutes the words of the value of variable name, each sepa‐
1071 rated by a blank. Braces insulate name from following charac‐
1072 ters which would otherwise be part of it. Shell variables have
1073 names consisting of letters and digits starting with a letter.
1074 The underscore character is considered a letter. If name is
1075 not a shell variable, but is set in the environment, then that
1076 value is returned (but some of the other forms given below are
1077 not available in this case).
1078 $name[selector]
1079 ${name[selector]}
1080 Substitutes only the selected words from the value of name.
1081 The selector is subjected to `$' substitution and may consist
1082 of a single number or two numbers separated by a `-'. The
1083 first word of a variable's value is numbered `1'. If the first
1084 number of a range is omitted it defaults to `1'. If the last
1085 member of a range is omitted it defaults to `$#name'. The se‐
1086 lector `*' selects all words. It is not an error for a range
1087 to be empty if the second argument is omitted or in range.
1088 $0 Substitutes the name of the file from which command input is
1089 being read. An error occurs if the name is not known.
1090 $number
1091 ${number}
1092 Equivalent to `$argv[number]'.
1093 $* Equivalent to `$argv', which is equivalent to `$argv[*]'.
1094 The `:' modifiers described under History substitution, except for
1096 `:p', can be applied to the substitutions above. More than one may be
1097 used. (+) Braces may be needed to insulate a variable substitution
1098 from a literal colon just as with History substitution (q.v.); any mod‐
1099 ifiers must appear within the braces.
1100 The following substitutions can not be modified with `:' modifiers.
1102 $?name
1104 ${?name}
1105 Substitutes the string `1' if name is set, `0' if it is not.
1106 $?0 Substitutes `1' if the current input filename is known, `0' if
1107 it is not. Always `0' in interactive shells.
1108 $#name
1109 ${#name}
1110 Substitutes the number of words in name.
1111 $# Equivalent to `$#argv'. (+)
1112 $%name
1113 ${%name}
1114 Substitutes the number of characters in name. (+)
1115 $%number
1116 ${%number}
1117 Substitutes the number of characters in $argv[number]. (+)
1118 $? Equivalent to `$status'. (+)
1119 $$ Substitutes the (decimal) process number of the (parent) shell.
1120 $! Substitutes the (decimal) process number of the last background
1121 process started by this shell. (+)
1122 $_ Substitutes the command line of the last command executed. (+)
1123 $< Substitutes a line from the standard input, with no further in‐
1124 terpretation thereafter. It can be used to read from the key‐
1125 board in a shell script. (+) While csh always quotes $<, as if
1126 it were equivalent to `$<:q', tcsh does not. Furthermore, when
1127 tcsh is waiting for a line to be typed the user may type an in‐
1128 terrupt to interrupt the sequence into which the line is to be
1129 substituted, but csh does not allow this.
1130 The editor command expand-variables, normally bound to `^X-$', can be
1132 used to interactively expand individual variables.
1133 Command, filename and directory stack substitution
1135 The remaining substitutions are applied selectively to the arguments of
1136 builtin commands. This means that portions of expressions which are
1137 not evaluated are not subjected to these expansions. For commands
1138 which are not internal to the shell, the command name is substituted
1139 separately from the argument list. This occurs very late, after input-
1140 output redirection is performed, and in a child of the main shell.
1141 Command substitution
1143 Command substitution is indicated by a command enclosed in ``'. The
1144 output from such a command is broken into separate words at blanks,
1145 tabs and newlines, and null words are discarded. The output is vari‐
1146 able and command substituted and put in place of the original string.
1147 Command substitutions inside double quotes (`"') retain blanks and
1149 tabs; only newlines force new words. The single final newline does not
1150 force a new word in any case. It is thus possible for a command sub‐
1151 stitution to yield only part of a word, even if the command outputs a
1152 complete line.
1153 By default, the shell since version 6.12 replaces all newline and car‐
1155 riage return characters in the command by spaces. If this is switched
1156 off by unsetting csubstnonl, newlines separate commands as usual.
1157 Filename substitution
1159 If a word contains any of the characters `*', `?', `[' or `{' or begins
1160 with the character `~' it is a candidate for filename substitution,
1161 also known as ``globbing''. This word is then regarded as a pattern
1162 (``glob-pattern''), and replaced with an alphabetically sorted list of
1163 file names which match the pattern.
1164 In matching filenames, the character `.' at the beginning of a filename
1166 or immediately following a `/', as well as the character `/' must be
1167 matched explicitly (unless either globdot or globstar or both are
1168 set(+)). The character `*' matches any string of characters, including
1169 the null string. The character `?' matches any single character. The
1170 sequence `[...]' matches any one of the characters enclosed. Within
1171 `[...]', a pair of characters separated by `-' matches any character
1172 lexically between the two.
1173 (+) Some glob-patterns can be negated: The sequence `[^...]' matches
1175 any single character not specified by the characters and/or ranges of
1176 characters in the braces.
1177 An entire glob-pattern can also be negated with `^':
1179 > echo *
1181 bang crash crunch ouch
1182 > echo ^cr*
1183 bang ouch
1184 Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or
1186 `~' (below) are not negated correctly.
1187 The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'. Left-
1189 to-right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
1190 `/usr/source/s1/oldls.c /usr/source/s1/ls.c'. The results of matches
1191 are sorted separately at a low level to preserve this order:
1192 `../{memo,*box}' might expand to `../memo ../box ../mbox'. (Note that
1193 `memo' was not sorted with the results of matching `*box'.) It is not
1194 an error when this construct expands to files which do not exist, but
1195 it is possible to get an error from a command to which the expanded
1196 list is passed. This construct may be nested. As a special case the
1197 words `{', `}' and `{}' are passed undisturbed.
1198 The character `~' at the beginning of a filename refers to home direc‐
1200 tories. Standing alone, i.e., `~', it expands to the invoker's home
1201 directory as reflected in the value of the home shell variable. When
1202 followed by a name consisting of letters, digits and `-' characters the
1203 shell searches for a user with that name and substitutes their home di‐
1204 rectory; thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
1205 `/usr/ken/chmach'. If the character `~' is followed by a character
1206 other than a letter or `/' or appears elsewhere than at the beginning
1207 of a word, it is left undisturbed. A command like `setenv MANPATH
1208 /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home direc‐
1209 tory substitution as one might hope.
1210 It is an error for a glob-pattern containing `*', `?', `[' or `~', with
1212 or without `^', not to match any files. However, only one pattern in a
1213 list of glob-patterns must match a file (so that, e.g., `rm *.a *.c
1214 *.o' would fail only if there were no files in the current directory
1215 ending in `.a', `.c', or `.o'), and if the nonomatch shell variable is
1216 set a pattern (or list of patterns) which matches nothing is left un‐
1217 changed rather than causing an error.
1218 The globstar shell variable can be set to allow `**' or `***' as a file
1220 glob pattern that matches any string of characters including `/', re‐
1221 cursively traversing any existing sub-directories. For example, `ls
1222 **.c' will list all the .c files in the current directory tree. If
1223 used by itself, it will match zero or more sub-directories (e.g. `ls
1224 /usr/include/**/time.h' will list any file named `time.h' in the
1225 /usr/include directory tree; `ls /usr/include/**time.h' will match any
1226 file in the /usr/include directory tree ending in `time.h'; and `ls
1227 /usr/include/**time**.h' will match any .h file with `time' either in a
1228 subdirectory name or in the filename itself). To prevent problems with
1229 recursion, the `**' glob-pattern will not descend into a symbolic link
1230 containing a directory. To override this, use `***' (+)
1231 The noglob shell variable can be set to prevent filename substitution,
1233 and the expand-glob editor command, normally bound to `^X-*', can be
1234 used to interactively expand individual filename substitutions.
1235 Directory stack substitution (+)
1237 The directory stack is a list of directories, numbered from zero, used
1238 by the pushd, popd and dirs builtin commands (q.v.). dirs can print,
1239 store in a file, restore and clear the directory stack at any time, and
1240 the savedirs and dirsfile shell variables can be set to store the di‐
1241 rectory stack automatically on logout and restore it on login. The
1242 dirstack shell variable can be examined to see the directory stack and
1243 set to put arbitrary directories into the directory stack.
1244 The character `=' followed by one or more digits expands to an entry in
1246 the directory stack. The special case `=-' expands to the last direc‐
1247 tory in the stack. For example,
1248 > dirs -v
1250 0 /usr/bin
1251 1 /usr/spool/uucp
1252 2 /usr/accts/sys
1253 > echo =1
1254 /usr/spool/uucp
1255 > echo =0/calendar
1256 /usr/bin/calendar
1257 > echo =-
1258 /usr/accts/sys
1259 The noglob and nonomatch shell variables and the expand-glob editor
1261 command apply to directory stack as well as filename substitutions.
1262 Other substitutions (+)
1264 There are several more transformations involving filenames, not
1265 strictly related to the above but mentioned here for completeness. Any
1266 filename may be expanded to a full path when the symlinks variable
1267 (q.v.) is set to `expand'. Quoting prevents this expansion, and the
1268 normalize-path editor command does it on demand. The normalize-command
1269 editor command expands commands in PATH into full paths on demand. Fi‐
1270 nally, cd and pushd interpret `-' as the old working directory (equiva‐
1271 lent to the shell variable owd). This is not a substitution at all,
1272 but an abbreviation recognized by only those commands. Nonetheless, it
1273 too can be prevented by quoting.
1274 Commands
1276 The next three sections describe how the shell executes commands and
1277 deals with their input and output.
1278 Simple commands, pipelines and sequences
1280 A simple command is a sequence of words, the first of which specifies
1281 the command to be executed. A series of simple commands joined by `|'
1282 characters forms a pipeline. The output of each command in a pipeline
1283 is connected to the input of the next.
1284 Simple commands and pipelines may be joined into sequences with `;',
1286 and will be executed sequentially. Commands and pipelines can also be
1287 joined into sequences with `||' or `&&', indicating, as in the C lan‐
1288 guage, that the second is to be executed only if the first fails or
1289 succeeds respectively.
1290 A simple command, pipeline or sequence may be placed in parentheses,
1292 `()', to form a simple command, which may in turn be a component of a
1293 pipeline or sequence. A command, pipeline or sequence can be executed
1294 without waiting for it to terminate by following it with an `&'.
1295 Builtin and non-builtin command execution
1297 Builtin commands are executed within the shell. If any component of a
1298 pipeline except the last is a builtin command, the pipeline is executed
1299 in a subshell.
1300 Parenthesized commands are always executed in a subshell.
1302 (cd; pwd); pwd
1304 thus prints the home directory, leaving you where you were (printing
1306 this after the home directory), while
1307 cd; pwd
1309 leaves you in the home directory. Parenthesized commands are most of‐
1311 ten used to prevent cd from affecting the current shell.
1312 When a command to be executed is found not to be a builtin command the
1314 shell attempts to execute the command via execve(2). Each word in the
1315 variable path names a directory in which the shell will look for the
1316 command. If the shell is not given a -f option, the shell hashes the
1317 names in these directories into an internal table so that it will try
1318 an execve(2) in only a directory where there is a possibility that the
1319 command resides there. This greatly speeds command location when a
1320 large number of directories are present in the search path. This hash‐
1321 ing mechanism is not used:
1322 1. If hashing is turned explicitly off via unhash.
1324 2. If the shell was given a -f argument.
1326 3. For each directory component of path which does not begin with a
1328 `/'.
1329 4. If the command contains a `/'.
1331 In the above four cases the shell concatenates each component of the
1333 path vector with the given command name to form a path name of a file
1334 which it then attempts to execute it. If execution is successful, the
1335 search stops.
1336 If the file has execute permissions but is not an executable to the
1338 system (i.e., it is neither an executable binary nor a script that
1339 specifies its interpreter), then it is assumed to be a file containing
1340 shell commands and a new shell is spawned to read it. The shell spe‐
1341 cial alias may be set to specify an interpreter other than the shell
1342 itself.
1343 On systems which do not understand the `#!' script interpreter conven‐
1345 tion the shell may be compiled to emulate it; see the version shell
1346 variable. If so, the shell checks the first line of the file to see if
1347 it is of the form `#!interpreter arg ...'. If it is, the shell starts
1348 interpreter with the given args and feeds the file to it on standard
1349 input.
1350 Input/output
1352 The standard input and standard output of a command may be redirected
1353 with the following syntax:
1354 < name Open file name (which is first variable, command and filename
1356 expanded) as the standard input.
1357 << word Read the shell input up to a line which is identical to word.
1358 word is not subjected to variable, filename or command substi‐
1359 tution, and each input line is compared to word before any sub‐
1360 stitutions are done on this input line. Unless a quoting `\',
1361 `"', `' or ``' appears in word variable and command substitu‐
1362 tion is performed on the intervening lines, allowing `\' to
1363 quote `$', `\' and ``'. Commands which are substituted have
1364 all blanks, tabs, and newlines preserved, except for the final
1365 newline which is dropped. The resultant text is placed in an
1366 anonymous temporary file which is given to the command as stan‐
1367 dard input.
1368 > name
1369 >! name
1370 >& name
1371 >&! name
1372 The file name is used as standard output. If the file does not
1373 exist then it is created; if the file exists, it is truncated,
1374 its previous contents being lost.
1375 If the shell variable noclobber is set, then the file must not
1377 exist or be a character special file (e.g., a terminal or
1378 `/dev/null') or an error results. This helps prevent acciden‐
1379 tal destruction of files. In this case the `!' forms can be
1380 used to suppress this check. If notempty is given in noclob‐
1381 ber, `>' is allowed on empty files; if ask is set, an in‐
1382 teracive confirmation is presented, rather than an error.
1383 The forms involving `&' route the diagnostic output into the
1385 specified file as well as the standard output. name is ex‐
1386 panded in the same way as `<' input filenames are.
1387 >> name
1388 >>& name
1389 >>! name
1390 >>&! name
1391 Like `>', but appends output to the end of name. If the shell
1392 variable noclobber is set, then it is an error for the file not
1393 to exist, unless one of the `!' forms is given.
1394 A command receives the environment in which the shell was invoked as
1396 modified by the input-output parameters and the presence of the command
1397 in a pipeline. Thus, unlike some previous shells, commands run from a
1398 file of shell commands have no access to the text of the commands by
1399 default; rather they receive the original standard input of the shell.
1400 The `<<' mechanism should be used to present inline data. This permits
1401 shell command scripts to function as components of pipelines and allows
1402 the shell to block read its input. Note that the default standard in‐
1403 put for a command run detached is not the empty file /dev/null, but the
1404 original standard input of the shell. If this is a terminal and if the
1405 process attempts to read from the terminal, then the process will block
1406 and the user will be notified (see Jobs).
1407 Diagnostic output may be directed through a pipe with the standard out‐
1409 put. Simply use the form `|&' rather than just `|'.
1410 The shell cannot presently redirect diagnostic output without also
1412 redirecting standard output, but `(command > output-file) >& error-
1413 file' is often an acceptable workaround. Either output-file or error-
1414 file may be `/dev/tty' to send output to the terminal.
1415 Features
1417 Having described how the shell accepts, parses and executes command
1418 lines, we now turn to a variety of its useful features.
1419 Control flow
1421 The shell contains a number of commands which can be used to regulate
1422 the flow of control in command files (shell scripts) and (in limited
1423 but useful ways) from terminal input. These commands all operate by
1424 forcing the shell to reread or skip in its input and, due to the imple‐
1425 mentation, restrict the placement of some of the commands.
1426 The foreach, switch, and while statements, as well as the if-then-else
1428 form of the if statement, require that the major keywords appear in a
1429 single simple command on an input line as shown below.
1430 If the shell's input is not seekable, the shell buffers up input when‐
1432 ever a loop is being read and performs seeks in this internal buffer to
1433 accomplish the rereading implied by the loop. (To the extent that this
1434 allows, backward gotos will succeed on non-seekable inputs.)
1435 Expressions
1437 The if, while and exit builtin commands use expressions with a common
1438 syntax. The expressions can include any of the operators described in
1439 the next three sections. Note that the @ builtin command (q.v.) has
1440 its own separate syntax.
1441 Logical, arithmetical and comparison operators
1443 These operators are similar to those of C and have the same precedence.
1444 They include
1445 || && | ^ & == != =~ !~ <= >=
1447 < > << >> + - * / % ! ~ ( )
1448 Here the precedence increases to the right, `==' `!=' `=~' and `!~',
1450 `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%' be‐
1451 ing, in groups, at the same level. The `==' `!=' `=~' and `!~' opera‐
1452 tors compare their arguments as strings; all others operate on numbers.
1453 The operators `=~' and `!~' are like `!=' and `==' except that the
1454 right hand side is a glob-pattern (see Filename substitution) against
1455 which the left hand operand is matched. This reduces the need for use
1456 of the switch builtin command in shell scripts when all that is really
1457 needed is pattern matching.
1458 Null or missing arguments are considered `0'. The results of all ex‐
1460 pressions are strings, which represent decimal numbers. It is impor‐
1461 tant to note that no two components of an expression can appear in the
1462 same word; except when adjacent to components of expressions which are
1463 syntactically significant to the parser (`&' `|' `<' `>' `(' `)') they
1464 should be surrounded by spaces.
1465 Command exit status
1467 Commands can be executed in expressions and their exit status returned
1468 by enclosing them in braces (`{}'). Remember that the braces should be
1469 separated from the words of the command by spaces. Command executions
1470 succeed, returning true, i.e., `1', if the command exits with status 0,
1471 otherwise they fail, returning false, i.e., `0'. If more detailed sta‐
1472 tus information is required then the command should be executed outside
1473 of an expression and the status shell variable examined.
1474 File inquiry operators
1476 Some of these operators perform true/false tests on files and related
1477 objects. They are of the form -op file, where op is one of
1478 r Read access
1480 w Write access
1481 x Execute access
1482 X Executable in the path or shell builtin, e.g., `-X ls' and `-X
1483 ls-F' are generally true, but `-X /bin/ls' is not (+)
1484 e Existence
1485 o Ownership
1486 z Zero size
1487 s Non-zero size (+)
1488 f Plain file
1489 d Directory
1490 l Symbolic link (+) *
1491 b Block special file (+)
1492 c Character special file (+)
1493 p Named pipe (fifo) (+) *
1494 S Socket special file (+) *
1495 u Set-user-ID bit is set (+)
1496 g Set-group-ID bit is set (+)
1497 k Sticky bit is set (+)
1498 t file (which must be a digit) is an open file descriptor for a
1499 terminal device (+)
1500 R Has been migrated (Convex only) (+)
1501 L Applies subsequent operators in a multiple-operator test to a
1502 symbolic link rather than to the file to which the link points
1503 (+) *
1504 file is command and filename expanded and then tested to see if it has
1506 the specified relationship to the real user. If file does not exist or
1507 is inaccessible or, for the operators indicated by `*', if the speci‐
1508 fied file type does not exist on the current system, then all inquiries
1509 return false, i.e., `0'.
1510 These operators may be combined for conciseness: `-xy file' is equiva‐
1512 lent to `-x file && -y file'. (+) For example, `-fx' is true (returns
1513 `1') for plain executable files, but not for directories.
1514 L may be used in a multiple-operator test to apply subsequent operators
1516 to a symbolic link rather than to the file to which the link points.
1517 For example, `-lLo' is true for links owned by the invoking user. Lr,
1518 Lw and Lx are always true for links and false for non-links. L has a
1519 different meaning when it is the last operator in a multiple-operator
1520 test; see below.
1521 It is possible but not useful, and sometimes misleading, to combine op‐
1523 erators which expect file to be a file with operators which do not
1524 (e.g., X and t). Following L with a non-file operator can lead to par‐
1525 ticularly strange results.
1526 Other operators return other information, i.e., not just `0' or `1'.
1528 (+) They have the same format as before; op may be one of
1529 A Last file access time, as the number of seconds since the
1531 epoch
1532 A: Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
1533 1993'
1534 M Last file modification time
1535 M: Like M, but in timestamp format
1536 C Last inode modification time
1537 C: Like C, but in timestamp format
1538 D Device number
1539 I Inode number
1540 F Composite file identifier, in the form device:inode
1541 L The name of the file pointed to by a symbolic link
1542 N Number of (hard) links
1543 P Permissions, in octal, without leading zero
1544 P: Like P, with leading zero
1545 Pmode Equivalent to `-P file & mode', e.g., `-P22 file' returns
1546 `22' if file is writable by group and other, `20' if by
1547 group only, and `0' if by neither
1548 Pmode: Like Pmode, with leading zero
1549 U Numeric userid
1550 U: Username, or the numeric userid if the username is unknown
1551 G Numeric groupid
1552 G: Groupname, or the numeric groupid if the groupname is un‐
1553 known
1554 Z Size, in bytes
1555 Only one of these operators may appear in a multiple-operator test, and
1557 it must be the last. Note that L has a different meaning at the end of
1558 and elsewhere in a multiple-operator test. Because `0' is a valid re‐
1559 turn value for many of these operators, they do not return `0' when
1560 they fail: most return `-1', and F returns `:'.
1561 If the shell is compiled with POSIX defined (see the version shell
1563 variable), the result of a file inquiry is based on the permission bits
1564 of the file and not on the result of the access(2) system call. For
1565 example, if one tests a file with -w whose permissions would ordinarily
1566 allow writing but which is on a file system mounted read-only, the test
1567 will succeed in a POSIX shell but fail in a non-POSIX shell.
1568 File inquiry operators can also be evaluated with the filetest builtin
1570 command (q.v.) (+).
1571 Jobs
1573 The shell associates a job with each pipeline. It keeps a table of
1574 current jobs, printed by the jobs command, and assigns them small inte‐
1575 ger numbers. When a job is started asynchronously with `&', the shell
1576 prints a line which looks like
1577 [1] 1234
1579 indicating that the job which was started asynchronously was job number
1581 1 and had one (top-level) process, whose process id was 1234.
1582 If you are running a job and wish to do something else you may hit the
1584 suspend key (usually `^Z'), which sends a STOP signal to the current
1585 job. The shell will then normally indicate that the job has been `Sus‐
1586 pended' and print another prompt. If the listjobs shell variable is
1587 set, all jobs will be listed like the jobs builtin command; if it is
1588 set to `long' the listing will be in long format, like `jobs -l'. You
1589 can then manipulate the state of the suspended job. You can put it in
1590 the ``background'' with the bg command or run some other commands and
1591 eventually bring the job back into the ``foreground'' with fg. (See
1592 also the run-fg-editor editor command.) A `^Z' takes effect immedi‐
1593 ately and is like an interrupt in that pending output and unread input
1594 are discarded when it is typed. The wait builtin command causes the
1595 shell to wait for all background jobs to complete.
1596 The `^]' key sends a delayed suspend signal, which does not generate a
1598 STOP signal until a program attempts to read(2) it, to the current job.
1599 This can usefully be typed ahead when you have prepared some commands
1600 for a job which you wish to stop after it has read them. The `^Y' key
1601 performs this function in csh(1); in tcsh, `^Y' is an editing command.
1602 (+)
1603 A job being run in the background stops if it tries to read from the
1605 terminal. Background jobs are normally allowed to produce output, but
1606 this can be disabled by giving the command `stty tostop'. If you set
1607 this tty option, then background jobs will stop when they try to pro‐
1608 duce output like they do when they try to read input.
1609 There are several ways to refer to jobs in the shell. The character
1611 `%' introduces a job name. If you wish to refer to job number 1, you
1612 can name it as `%1'. Just naming a job brings it to the foreground;
1613 thus `%1' is a synonym for `fg %1', bringing job 1 back into the fore‐
1614 ground. Similarly, saying `%1 &' resumes job 1 in the background, just
1615 like `bg %1'. A job can also be named by an unambiguous prefix of the
1616 string typed in to start it: `%ex' would normally restart a suspended
1617 ex(1) job, if there were only one suspended job whose name began with
1618 the string `ex'. It is also possible to say `%?string' to specify a
1619 job whose text contains string, if there is only one such job.
1620 The shell maintains a notion of the current and previous jobs. In out‐
1622 put pertaining to jobs, the current job is marked with a `+' and the
1623 previous job with a `-'. The abbreviations `%+', `%', and (by analogy
1624 with the syntax of the history mechanism) `%%' all refer to the current
1625 job, and `%-' refers to the previous job.
1626 The job control mechanism requires that the stty(1) option `new' be set
1628 on some systems. It is an artifact from a `new' implementation of the
1629 tty driver which allows generation of interrupt characters from the
1630 keyboard to tell jobs to stop. See stty(1) and the setty builtin com‐
1631 mand for details on setting options in the new tty driver.
1632 Status reporting
1634 The shell learns immediately whenever a process changes state. It nor‐
1635 mally informs you whenever a job becomes blocked so that no further
1636 progress is possible, but only right before it prints a prompt. This
1637 is done so that it does not otherwise disturb your work. If, however,
1638 you set the shell variable notify, the shell will notify you immedi‐
1639 ately of changes of status in background jobs. There is also a shell
1640 command notify which marks a single process so that its status changes
1641 will be immediately reported. By default notify marks the current
1642 process; simply say `notify' after starting a background job to mark
1643 it.
1644 When you try to leave the shell while jobs are stopped, you will be
1646 warned that `There are suspended jobs.' You may use the jobs command to
1647 see what they are. If you do this or immediately try to exit again,
1648 the shell will not warn you a second time, and the suspended jobs will
1649 be terminated.
1650 Automatic, periodic and timed events (+)
1652 There are various ways to run commands and take other actions automati‐
1653 cally at various times in the ``life cycle'' of the shell. They are
1654 summarized here, and described in detail under the appropriate Builtin
1655 commands, Special shell variables and Special aliases.
1656 The sched builtin command puts commands in a scheduled-event list, to
1658 be executed by the shell at a given time.
1659 The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
1661 aliases can be set, respectively, to execute commands when the shell
1662 wants to ring the bell, when the working directory changes, every tpe‐
1663 riod minutes, before each prompt, before each command gets executed,
1664 after each command gets executed, and when a job is started or is
1665 brought into the foreground.
1666 The autologout shell variable can be set to log out or lock the shell
1668 after a given number of minutes of inactivity.
1669 The mail shell variable can be set to check for new mail periodically.
1671 The printexitvalue shell variable can be set to print the exit status
1673 of commands which exit with a status other than zero.
1674 The rmstar shell variable can be set to ask the user, when `rm *' is
1676 typed, if that is really what was meant.
1677 The time shell variable can be set to execute the time builtin command
1679 after the completion of any process that takes more than a given number
1680 of CPU seconds.
1681 The watch and who shell variables can be set to report when selected
1683 users log in or out, and the log builtin command reports on those users
1684 at any time.
1685 Native Language System support (+)
1687 The shell is eight bit clean (if so compiled; see the version shell
1688 variable) and thus supports character sets needing this capability.
1689 NLS support differs depending on whether or not the shell was compiled
1690 to use the system's NLS (again, see version). In either case, 7-bit
1691 ASCII is the default character code (e.g., the classification of which
1692 characters are printable) and sorting, and changing the LANG or
1693 LC_CTYPE environment variables causes a check for possible changes in
1694 these respects.
1695 When using the system's NLS, the setlocale(3) function is called to de‐
1697 termine appropriate character code/classification and sorting (e.g., a
1698 'en_CA.UTF-8' would yield "UTF-8" as a character code). This function
1699 typically examines the LANG and LC_CTYPE environment variables; refer
1700 to the system documentation for further details. When not using the
1701 system's NLS, the shell simulates it by assuming that the ISO 8859-1
1702 character set is used whenever either of the LANG and LC_CTYPE vari‐
1703 ables are set, regardless of their values. Sorting is not affected for
1704 the simulated NLS.
1705 In addition, with both real and simulated NLS, all printable characters
1707 in the range \200-\377, i.e., those that have M-char bindings, are au‐
1708 tomatically rebound to self-insert-command. The corresponding binding
1709 for the escape-char sequence, if any, is left alone. These characters
1710 are not rebound if the NOREBIND environment variable is set. This may
1711 be useful for the simulated NLS or a primitive real NLS which assumes
1712 full ISO 8859-1. Otherwise, all M-char bindings in the range \240-\377
1713 are effectively undone. Explicitly rebinding the relevant keys with
1714 bindkey is of course still possible.
1715 Unknown characters (i.e., those that are neither printable nor control
1717 characters) are printed in the format \nnn. If the tty is not in 8 bit
1718 mode, other 8 bit characters are printed by converting them to ASCII
1719 and using standout mode. The shell never changes the 7/8 bit mode of
1720 the tty and tracks user-initiated changes of 7/8 bit mode. NLS users
1721 (or, for that matter, those who want to use a meta key) may need to ex‐
1722 plicitly set the tty in 8 bit mode through the appropriate stty(1) com‐
1723 mand in, e.g., the ~/.login file.
1724 OS variant support (+)
1726 A number of new builtin commands are provided to support features in
1727 particular operating systems. All are described in detail in the
1728 Builtin commands section.
1729 On systems that support TCF (aix-ibm370, aix-ps2), getspath and
1731 setspath get and set the system execution path, getxvers and setxvers
1732 get and set the experimental version prefix and migrate migrates pro‐
1733 cesses between sites. The jobs builtin prints the site on which each
1734 job is executing.
1735 Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD op‐
1737 erating system.
1738 Under Domain/OS, inlib adds shared libraries to the current environ‐
1740 ment, rootnode changes the rootnode and ver changes the systype.
1741 Under Mach, setpath is equivalent to Mach's setpath(1).
1743 Under Masscomp/RTU and Harris CX/UX, universe sets the universe.
1745 Under Harris CX/UX, ucb or att runs a command under the specified uni‐
1747 verse.
1748 Under Convex/OS, warp prints or sets the universe.
1750 The VENDOR, OSTYPE and MACHTYPE environment variables indicate respec‐
1752 tively the vendor, operating system and machine type (microprocessor
1753 class or machine model) of the system on which the shell thinks it is
1754 running. These are particularly useful when sharing one's home direc‐
1755 tory between several types of machines; one can, for example,
1756 set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)
1758 in one's ~/.login and put executables compiled for each machine in the
1760 appropriate directory.
1761 The version shell variable indicates what options were chosen when the
1763 shell was compiled.
1764 Note also the newgrp builtin, the afsuser and echo_style shell vari‐
1766 ables and the system-dependent locations of the shell's input files
1767 (see FILES).
1768 Signal handling
1770 Login shells ignore interrupts when reading the file ~/.logout. The
1771 shell ignores quit signals unless started with -q. Login shells catch
1772 the terminate signal, but non-login shells inherit the terminate behav‐
1773 ior from their parents. Other signals have the values which the shell
1774 inherited from its parent.
1775 In shell scripts, the shell's handling of interrupt and terminate sig‐
1777 nals can be controlled with onintr, and its handling of hangups can be
1778 controlled with hup and nohup.
1779 The shell exits on a hangup (see also the logout shell variable). By
1781 default, the shell's children do too, but the shell does not send them
1782 a hangup when it exits. hup arranges for the shell to send a hangup to
1783 a child when it exits, and nohup sets a child to ignore hangups.
1784 Terminal management (+)
1786 The shell uses three different sets of terminal (``tty'') modes:
1787 `edit', used when editing, `quote', used when quoting literal charac‐
1788 ters, and `execute', used when executing commands. The shell holds
1789 some settings in each mode constant, so commands which leave the tty in
1790 a confused state do not interfere with the shell. The shell also
1791 matches changes in the speed and padding of the tty. The list of tty
1792 modes that are kept constant can be examined and modified with the
1793 setty builtin. Note that although the editor uses CBREAK mode (or its
1794 equivalent), it takes typed-ahead characters anyway.
1795 The echotc, settc and telltc commands can be used to manipulate and de‐
1797 bug terminal capabilities from the command line.
1798 On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win‐
1800 dow resizing automatically and adjusts the environment variables LINES
1801 and COLUMNS if set. If the environment variable TERMCAP contains li#
1802 and co# fields, the shell adjusts them to reflect the new window size.
1803
1805 The next sections of this manual describe all of the available Builtin
1806 commands, Special aliases and Special shell variables.
1807 Builtin commands
1809 %job A synonym for the fg builtin command.
1810 %job & A synonym for the bg builtin command.
1812 : Does nothing, successfully.
1814 @
1816 @ name = expr
1817 @ name[index] = expr
1818 @ name++|--
1819 @ name[index]++|--
1820 The first form prints the values of all shell variables.
1821 The second form assigns the value of expr to name. The third
1823 form assigns the value of expr to the index'th component of
1824 name; both name and its index'th component must already exist.
1825 expr may contain the operators `*', `+', etc., as in C. If
1827 expr contains `<', `>', `&' or `' then at least that part of
1828 expr must be placed within `()'. Note that the syntax of expr
1829 has nothing to do with that described under Expressions.
1830 The fourth and fifth forms increment (`++') or decrement (`--')
1832 name or its index'th component.
1833 The space between `@' and name is required. The spaces between
1835 name and `=' and between `=' and expr are optional. Components
1836 of expr must be separated by spaces.
1837 alias [name [wordlist]]
1839 Without arguments, prints all aliases. With name, prints the
1840 alias for name. With name and wordlist, assigns wordlist as
1841 the alias of name. wordlist is command and filename substi‐
1842 tuted. name may not be `alias' or `unalias'. See also the un‐
1843 alias builtin command.
1844 alloc Shows the amount of dynamic memory acquired, broken down into
1846 used and free memory. With an argument shows the number of
1847 free and used blocks in each size category. The categories
1848 start at size 8 and double at each step. This command's output
1849 may vary across system types, because systems other than the
1850 VAX may use a different memory allocator.
1851 bg [%job ...]
1853 Puts the specified jobs (or, without arguments, the current
1854 job) into the background, continuing each if it is stopped.
1855 job may be a number, a string, `', `%', `+' or `-' as described
1856 under Jobs.
1857 bindkey [-l|-d|-e|-v|-u] (+)
1859 bindkey [-a] [-b] [-k] [-r] [--] key (+)
1860 bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
1861 Without options, the first form lists all bound keys and the
1862 editor command to which each is bound, the second form lists
1863 the editor command to which key is bound and the third form
1864 binds the editor command command to key. Options include:
1865 -l Lists all editor commands and a short description of each.
1867 -d Binds all keys to the standard bindings for the default ed‐
1868 itor, as per -e and -v below.
1869 -e Binds all keys to emacs(1)-style bindings. Unsets vimode.
1870 -v Binds all keys to vi(1)-style bindings. Sets vimode.
1871 -a Lists or changes key-bindings in the alternative key map.
1872 This is the key map used in vimode command mode.
1873 -b key is interpreted as a control character written ^charac‐
1874 ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char‐
1875 acter written M-character (e.g., `M-A'), a function key
1876 written F-string (e.g., `F-string'), or an extended prefix
1877 key written X-character (e.g., `X-A').
1878 -k key is interpreted as a symbolic arrow key name, which may
1879 be one of `down', `up', `left' or `right'.
1880 -r Removes key's binding. Be careful: `bindkey -r' does not
1881 bind key to self-insert-command (q.v.), it unbinds key com‐
1882 pletely.
1883 -c command is interpreted as a builtin or external command in‐
1884 stead of an editor command.
1885 -s command is taken as a literal string and treated as termi‐
1886 nal input when key is typed. Bound keys in command are
1887 themselves reinterpreted, and this continues for ten levels
1888 of interpretation.
1889 -- Forces a break from option processing, so the next word is
1890 taken as key even if it begins with '-'.
1891 -u (or any invalid option)
1892 Prints a usage message.
1893 key may be a single character or a string. If a command is
1895 bound to a string, the first character of the string is bound
1896 to sequence-lead-in and the entire string is bound to the com‐
1897 mand.
1898 Control characters in key can be literal (they can be typed by
1900 preceding them with the editor command quoted-insert, normally
1901 bound to `^V') or written caret-character style, e.g., `^A'.
1902 Delete is written `^?' (caret-question mark). key and command
1903 can contain backslashed escape sequences (in the style of Sys‐
1904 tem V echo(1)) as follows:
1905 \a Bell
1907 \b Backspace
1908 \e Escape
1909 \f Form feed
1910 \n Newline
1911 \r Carriage return
1912 \t Horizontal tab
1913 \v Vertical tab
1914 \nnn The ASCII character corresponding to the octal num‐
1915 ber nnn
1916 `\' nullifies the special meaning of the following character,
1918 if it has any, notably `\' and `^'.
1919 bs2cmd bs2000-command (+)
1921 Passes bs2000-command to the BS2000 command interpreter for ex‐
1922 ecution. Only non-interactive commands can be executed, and it
1923 is not possible to execute any command that would overlay the
1924 image of the current process, like /EXECUTE or /CALL-PROCEDURE.
1925 (BS2000 only)
1926 break Causes execution to resume after the end of the nearest enclos‐
1928 ing foreach or while. The remaining commands on the current
1929 line are executed. Multi-level breaks are thus possible by
1930 writing them all on one line.
1931 breaksw Causes a break from a switch, resuming after the endsw.
1933 builtins (+)
1935 Prints the names of all builtin commands.
1936 bye (+) A synonym for the logout builtin command. Available only if
1938 the shell was so compiled; see the version shell variable.
1939 case label:
1941 A label in a switch statement as discussed below.
1942 cd [-p] [-l] [-n|-v] [I--] [name]
1944 If a directory name is given, changes the shell's working di‐
1945 rectory to name. If not, changes to home, unless the cdtohome
1946 variable is not set, in which case a name is required. If name
1947 is `-' it is interpreted as the previous working directory (see
1948 Other substitutions). (+) If name is not a subdirectory of the
1949 current directory (and does not begin with `/', `./' or `../'),
1950 each component of the variable cdpath is checked to see if it
1951 has a subdirectory name. Finally, if all else fails but name
1952 is a shell variable whose value begins with `/' or '.', then
1953 this is tried to see if it is a directory, and the -p option is
1954 implied.
1955 With -p, prints the final directory stack, just like dirs. The
1957 -l, -n and -v flags have the same effect on cd as on dirs, and
1958 they imply -p. (+) Using -- forces a break from option pro‐
1959 cessing so the next word is taken as the directory name even if
1960 it begins with '-'. (+)
1961 See also the implicitcd and cdtohome shell variables.
1963 chdir A synonym for the cd builtin command.
1965 complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
1967 Without arguments, lists all completions. With command, lists
1968 completions for command. With command and word etc., defines
1969 completions.
1970 command may be a full command name or a glob-pattern (see File‐
1972 name substitution). It can begin with `-' to indicate that
1973 completion should be used only when command is ambiguous.
1974 word specifies which word relative to the current word is to be
1976 completed, and may be one of the following:
1977 c Current-word completion. pattern is a glob-pattern
1979 which must match the beginning of the current word on
1980 the command line. pattern is ignored when completing
1981 the current word.
1982 C Like c, but includes pattern when completing the cur‐
1983 rent word.
1984 n Next-word completion. pattern is a glob-pattern which
1985 must match the beginning of the previous word on the
1986 command line.
1987 N Like n, but must match the beginning of the word two
1988 before the current word.
1989 p Position-dependent completion. pattern is a numeric
1990 range, with the same syntax used to index shell vari‐
1991 ables, which must include the current word.
1992 list, the list of possible completions, may be one of the fol‐
1994 lowing:
1995 a Aliases
1997 b Bindings (editor commands)
1998 c Commands (builtin or external commands)
1999 C External commands which begin with the supplied
2000 path prefix
2001 d Directories
2002 D Directories which begin with the supplied path pre‐
2003 fix
2004 e Environment variables
2005 f Filenames
2006 F Filenames which begin with the supplied path prefix
2007 g Groupnames
2008 j Jobs
2009 l Limits
2010 n Nothing
2011 s Shell variables
2012 S Signals
2013 t Plain (``text'') files
2014 T Plain (``text'') files which begin with the sup‐
2015 plied path prefix
2016 v Any variables
2017 u Usernames
2018 x Like n, but prints select when list-choices is
2019 used.
2020 X Completions
2021 $var Words from the variable var
2022 (...) Words from the given list
2023 `...` Words from the output of command
2024 select is an optional glob-pattern. If given, words from only
2026 list that match select are considered and the fignore shell
2027 variable is ignored. The last three types of completion may
2028 not have a select pattern, and x uses select as an explanatory
2029 message when the list-choices editor command is used.
2030 suffix is a single character to be appended to a successful
2032 completion. If null, no character is appended. If omitted (in
2033 which case the fourth delimiter can also be omitted), a slash
2034 is appended to directories and a space to other words.
2035 command invoked from `...` version has additional environment
2037 variable set, the variable name is COMMAND_LINE and contains
2038 (as its name indicates) contents of the current (already typed
2039 in) command line. One can examine and use contents of the
2040 COMMAND_LINE variable in her custom script to build more so‐
2041 phisticated completions (see completion for svn(1) included in
2042 this package).
2043 Now for some examples. Some commands take only directories as
2045 arguments, so there's no point completing plain files.
2046 > complete cd 'p/1/d/'
2048 completes only the first word following `cd' (`p/1') with a di‐
2050 rectory. p-type completion can also be used to narrow down
2051 command completion:
2052 > co[^D]
2054 complete compress
2055 > complete -co* 'p/0/(compress)/'
2056 > co[^D]
2057 > compress
2058 This completion completes commands (words in position 0, `p/0')
2060 which begin with `co' (thus matching `co*') to `compress' (the
2061 only word in the list). The leading `-' indicates that this
2062 completion is to be used with only ambiguous commands.
2063 > complete find 'n/-user/u/'
2065 is an example of n-type completion. Any word following `find'
2067 and immediately following `-user' is completed from the list of
2068 users.
2069 > complete cc 'c/-I/d/'
2071 demonstrates c-type completion. Any word following `cc' and
2073 beginning with `-I' is completed as a directory. `-I' is not
2074 taken as part of the directory because we used lowercase c.
2075 Different lists are useful with different commands.
2077 > complete alias 'p/1/a/'
2079 > complete man 'p/*/c/'
2080 > complete set 'p/1/s/'
2081 > complete true 'p/1/x:Truth has no options./'
2082 These complete words following `alias' with aliases, `man' with
2084 commands, and `set' with shell variables. `true' doesn't have
2085 any options, so x does nothing when completion is attempted and
2086 prints `Truth has no options.' when completion choices are
2087 listed.
2088 Note that the man example, and several other examples below,
2090 could just as well have used 'c/*' or 'n/*' as 'p/*'.
2091 Words can be completed from a variable evaluated at completion
2093 time,
2094 > complete ftp 'p/1/$hostnames/'
2096 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
2097 > ftp [^D]
2098 rtfm.mit.edu tesla.ee.cornell.edu
2099 > ftp [^C]
2100 > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
2101 uunet.uu.net)
2102 > ftp [^D]
2103 rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net
2104 or from a command run at completion time:
2106 > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
2108 > kill -9 [^D]
2109 23113 23377 23380 23406 23429 23529 23530 PID
2110 Note that the complete command does not itself quote its argu‐
2112 ments, so the braces, space and `$' in `{print $1}' must be
2113 quoted explicitly.
2114 One command can have multiple completions:
2116 > complete dbx 'p/2/(core)/' 'p/*/c/'
2118 completes the second argument to `dbx' with the word `core' and
2120 all other arguments with commands. Note that the positional
2121 completion is specified before the next-word completion. Be‐
2122 cause completions are evaluated from left to right, if the
2123 next-word completion were specified first it would always match
2124 and the positional completion would never be executed. This is
2125 a common mistake when defining a completion.
2126 The select pattern is useful when a command takes files with
2128 only particular forms as arguments. For example,
2129 > complete cc 'p/*/f:*.[cao]/'
2131 completes `cc' arguments to files ending in only `.c', `.a', or
2133 `.o'. select can also exclude files, using negation of a glob-
2134 pattern as described under Filename substitution. One might
2135 use
2136 > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'
2138 to exclude precious source code from `rm' completion. Of
2140 course, one could still type excluded names manually or over‐
2141 ride the completion mechanism using the complete-word-raw or
2142 list-choices-raw editor commands (q.v.).
2143 The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
2145 respectively, but they use the select argument in a different
2146 way: to restrict completion to files beginning with a particu‐
2147 lar path prefix. For example, the Elm mail program uses `=' as
2148 an abbreviation for one's mail directory. One might use
2149 > complete elm c@=@F:$HOME/Mail/@
2151 to complete `elm -f =' as if it were `elm -f ~/Mail/'. Note
2153 that we used `@' instead of `/' to avoid confusion with the se‐
2154 lect argument, and we used `$HOME' instead of `~' because home
2155 directory substitution works at only the beginning of a word.
2156 suffix is used to add a nonstandard suffix (not space or `/'
2158 for directories) to completed words.
2159 > complete finger 'c/*@/$hostnames/' 'p/1/u/@'
2161 completes arguments to `finger' from the list of users, appends
2163 an `@', and then completes after the `@' from the `hostnames'
2164 variable. Note again the order in which the completions are
2165 specified.
2166 Finally, here's a complex example for inspiration:
2168 > complete find \
2170 'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
2171 ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
2172 'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
2173 'n/-type/(b c d f l p s)/' \
2174 ´c/-/(name newer cpio ncpio exec ok user \
2175 group fstype type atime ctime depth inum \
2176 ls mtime nogroup nouser perm print prune \
2177 size xdev)/' \
2178 'p/*/d/'
2179 This completes words following `-name', `-newer', `-cpio' or
2181 `ncpio' (note the pattern which matches both) to files, words
2182 following `-exec' or `-ok' to commands, words following `user'
2183 and `group' to users and groups respectively and words follow‐
2184 ing `-fstype' or `-type' to members of the given lists. It
2185 also completes the switches themselves from the given list
2186 (note the use of c-type completion) and completes anything not
2187 otherwise completed to a directory. Whew.
2188 Remember that programmed completions are ignored if the word
2190 being completed is a tilde substitution (beginning with `~') or
2191 a variable (beginning with `$'). See also the uncomplete
2192 builtin command.
2193 continue
2195 Continues execution of the nearest enclosing while or foreach.
2196 The rest of the commands on the current line are executed.
2197 default:
2199 Labels the default case in a switch statement. It should come
2200 after all case labels.
2201 dirs [-l] [-n|-v]
2203 dirs -S|-L [filename] (+)
2204 dirs -c (+)
2205 The first form prints the directory stack. The top of the
2206 stack is at the left and the first directory in the stack is
2207 the current directory. With -l, `~' or `~name' in the output
2208 is expanded explicitly to home or the pathname of the home di‐
2209 rectory for user name. (+) With -n, entries are wrapped before
2210 they reach the edge of the screen. (+) With -v, entries are
2211 printed one per line, preceded by their stack positions. (+)
2212 If more than one of -n or -v is given, -v takes precedence. -p
2213 is accepted but does nothing.
2214 With -S, the second form saves the directory stack to filename
2216 as a series of cd and pushd commands. With -L, the shell
2217 sources filename, which is presumably a directory stack file
2218 saved by the -S option or the savedirs mechanism. In either
2219 case, dirsfile is used if filename is not given and ~/.cshdirs
2220 is used if dirsfile is unset.
2221 Note that login shells do the equivalent of `dirs -L' on
2223 startup and, if savedirs is set, `dirs -S' before exiting. Be‐
2224 cause only ~/.tcshrc is normally sourced before ~/.cshdirs,
2225 dirsfile should be set in ~/.tcshrc rather than ~/.login.
2226 The last form clears the directory stack.
2228 echo [-n] word ...
2230 Writes each word to the shell's standard output, separated by
2231 spaces and terminated with a newline. The echo_style shell
2232 variable may be set to emulate (or not) the flags and escape
2233 sequences of the BSD and/or System V versions of echo; see
2234 echo(1).
2235 echotc [-sv] arg ... (+)
2237 Exercises the terminal capabilities (see termcap(5)) in args.
2238 For example, 'echotc home' sends the cursor to the home posi‐
2239 tion, 'echotc cm 3 10' sends it to column 3 and row 10, and
2240 'echotc ts 0; echo "This is a test."; echotc fs' prints "This
2241 is a test." in the status line.
2242 If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
2244 value of that capability ("yes" or "no" indicating that the
2245 terminal does or does not have that capability). One might use
2246 this to make the output from a shell script less verbose on
2247 slow terminals, or limit command output to the number of lines
2248 on the screen:
2249 > set history=`echotc lines`
2251 > @ history--
2252 Termcap strings may contain wildcards which will not echo cor‐
2254 rectly. One should use double quotes when setting a shell
2255 variable to a terminal capability string, as in the following
2256 example that places the date in the status line:
2257 > set tosl="`echotc ts 0`"
2259 > set frsl="`echotc fs`"
2260 > echo -n "$tosl";date; echo -n "$frsl"
2261 With -s, nonexistent capabilities return the empty string
2263 rather than causing an error. With -v, messages are verbose.
2264 else
2266 end
2267 endif
2268 endsw See the description of the foreach, if, switch, and while
2269 statements below.
2270 eval arg ...
2272 Treats the arguments as input to the shell and executes the re‐
2273 sulting command(s) in the context of the current shell. This
2274 is usually used to execute commands generated as the result of
2275 command or variable substitution, because parsing occurs before
2276 these substitutions. See tset(1) for a sample use of eval.
2277 exec command
2279 Executes the specified command in place of the current shell.
2280 exit [expr]
2282 The shell exits either with the value of the specified expr (an
2283 expression, as described under Expressions) or, without expr,
2284 with the value 0.
2285 fg [%job ...]
2287 Brings the specified jobs (or, without arguments, the current
2288 job) into the foreground, continuing each if it is stopped.
2289 job may be a number, a string, `', `%', `+' or `-' as described
2290 under Jobs. See also the run-fg-editor editor command.
2291 filetest -op file ... (+)
2293 Applies op (which is a file inquiry operator as described under
2294 File inquiry operators) to each file and returns the results as
2295 a space-separated list.
2296 foreach name (wordlist)
2298 ...
2299 end Successively sets the variable name to each member of wordlist
2300 and executes the sequence of commands between this command and
2301 the matching end. (Both foreach and end must appear alone on
2302 separate lines.) The builtin command continue may be used to
2303 continue the loop prematurely and the builtin command break to
2304 terminate it prematurely. When this command is read from the
2305 terminal, the loop is read once prompting with `foreach? ' (or
2306 prompt2) before any statements in the loop are executed. If
2307 you make a mistake typing in a loop at the terminal you can rub
2308 it out.
2309 getspath (+)
2311 Prints the system execution path. (TCF only)
2312 getxvers (+)
2314 Prints the experimental version prefix. (TCF only)
2315 glob wordlist
2317 Like echo, but the `-n' parameter is not recognized and words
2318 are delimited by null characters in the output. Useful for
2319 programs which wish to use the shell to filename expand a list
2320 of words.
2321 goto word
2323 word is filename and command-substituted to yield a string of
2324 the form `label'. The shell rewinds its input as much as pos‐
2325 sible, searches for a line of the form `label:', possibly pre‐
2326 ceded by blanks or tabs, and continues execution after that
2327 line.
2328 hashstat
2330 Prints a statistics line indicating how effective the internal
2331 hash table has been at locating commands (and avoiding exec's).
2332 An exec is attempted for each component of the path where the
2333 hash function indicates a possible hit, and in each component
2334 which does not begin with a `/'.
2335 On machines without vfork(2), prints only the number and size
2337 of hash buckets.
2338 history [-hTr] [n]
2340 history -S|-L|-M [filename] (+)
2341 history -c (+)
2342 The first form prints the history event list. If n is given
2343 only the n most recent events are printed or saved. With -h,
2344 the history list is printed without leading numbers. If -T is
2345 specified, timestamps are printed also in comment form. (This
2346 can be used to produce files suitable for loading with 'history
2347 -L' or 'source -h'.) With -r, the order of printing is most
2348 recent first rather than oldest first.
2349 With -S, the second form saves the history list to filename.
2351 If the first word of the savehist shell variable is set to a
2352 number, at most that many lines are saved. If the second word
2353 of savehist is set to `merge', the history list is merged with
2354 the existing history file instead of replacing it (if there is
2355 one) and sorted by time stamp. (+) Merging is intended for an
2356 environment like the X Window System with several shells in si‐
2357 multaneous use. If the second word of savehist is `merge' and
2358 the third word is set to `lock', the history file update will
2359 be serialized with other shell sessions that would possibly
2360 like to merge history at exactly the same time.
2361 With -L, the shell appends filename, which is presumably a his‐
2363 tory list saved by the -S option or the savehist mechanism, to
2364 the history list. -M is like -L, but the contents of filename
2365 are merged into the history list and sorted by timestamp. In
2366 either case, histfile is used if filename is not given and
2367 ~/.history is used if histfile is unset. `history -L' is ex‐
2368 actly like 'source -h' except that it does not require a file‐
2369 name.
2370 Note that login shells do the equivalent of `history -L' on
2372 startup and, if savehist is set, `history -S' before exiting.
2373 Because only ~/.tcshrc is normally sourced before ~/.history,
2374 histfile should be set in ~/.tcshrc rather than ~/.login.
2375 If histlit is set, the first and second forms print and save
2377 the literal (unexpanded) form of the history list.
2378 The last form clears the history list.
2380 hup [command] (+)
2382 With command, runs command such that it will exit on a hangup
2383 signal and arranges for the shell to send it a hangup signal
2384 when the shell exits. Note that commands may set their own re‐
2385 sponse to hangups, overriding hup. Without an argument, causes
2386 the non-interactive shell only to exit on a hangup for the re‐
2387 mainder of the script. See also Signal handling and the nohup
2388 builtin command.
2389 if (expr) command
2391 If expr (an expression, as described under Expressions) evalu‐
2392 ates true, then command is executed. Variable substitution on
2393 command happens early, at the same time it does for the rest of
2394 the if command. command must be a simple command, not an
2395 alias, a pipeline, a command list or a parenthesized command
2396 list, but it may have arguments. Input/output redirection oc‐
2397 curs even if expr is false and command is thus not executed;
2398 this is a bug.
2399 if (expr) then
2401 ...
2402 else if (expr2) then
2403 ...
2404 else
2405 ...
2406 endif If the specified expr is true then the commands to the first
2407 else are executed; otherwise if expr2 is true then the commands
2408 to the second else are executed, etc. Any number of else-if
2409 pairs are possible; only one endif is needed. The else part is
2410 likewise optional. (The words else and endif must appear at
2411 the beginning of input lines; the if must appear alone on its
2412 input line or after an else.)
2413 inlib shared-library ... (+)
2415 Adds each shared-library to the current environment. There is
2416 no way to remove a shared library. (Domain/OS only)
2417 jobs [-l]
2419 Lists the active jobs. With -l, lists process IDs in addition
2420 to the normal information. On TCF systems, prints the site on
2421 which each job is executing.
2422 kill [-s signal] %job|pid ...
2424 kill -l The first and second forms sends the specified signal (or, if
2425 none is given, the TERM (terminate) signal) to the specified
2426 jobs or processes. job may be a number, a string, `', `%', `+'
2427 or `-' as described under Jobs. Signals are either given by
2428 number or by name (as given in /usr/include/signal.h, stripped
2429 of the prefix `SIG'). There is no default job; saying just
2430 `kill' does not send a signal to the current job. If the sig‐
2431 nal being sent is TERM (terminate) or HUP (hangup), then the
2432 job or process is sent a CONT (continue) signal as well. The
2433 third form lists the signal names.
2434 limit [-h] [resource [maximum-use]]
2436 Limits the consumption by the current process and each process
2437 it creates to not individually exceed maximum-use on the speci‐
2438 fied resource. If no maximum-use is given, then the current
2439 limit is printed; if no resource is given, then all limitations
2440 are given. If the -h flag is given, the hard limits are used
2441 instead of the current limits. The hard limits impose a ceil‐
2442 ing on the values of the current limits. Only the super-user
2443 may raise the hard limits, but a user may lower or raise the
2444 current limits within the legal range.
2445 Controllable resources currently include (if supported by the
2447 OS):
2448 cputime
2450 the maximum number of cpu-seconds to be used by each
2451 process
2452 filesize
2454 the largest single file which can be created
2455 datasize
2457 the maximum growth of the data+stack region via sbrk(2)
2458 beyond the end of the program text
2459 stacksize
2461 the maximum size of the automatically-extended stack re‐
2462 gion
2463 coredumpsize
2465 the size of the largest core dump that will be created
2466 memoryuse
2468 the maximum amount of physical memory a process may have
2469 allocated to it at a given time
2470 NOTE: Changing this value has no effect. Support has
2472 been removed from Linux kernel v2.6 and newer.
2473 vmemoryuse
2475 the maximum amount of virtual memory a process may have
2476 allocated to it at a given time (address space)
2477 vmemoryuse
2479 the maximum amount of virtual memory a process may have
2480 allocated to it at a given time
2481 heapsize
2483 the maximum amount of memory a process may allocate per
2484 brk() system call
2485 descriptors or openfiles
2487 the maximum number of open files for this process
2488 pseudoterminals
2490 the maximum number of pseudo-terminals for this user
2491 kqueues
2493 the maximum number of kqueues allocated for this process
2494 concurrency
2496 the maximum number of threads for this process
2497 memorylocked
2499 the maximum size which a process may lock into memory
2500 using mlock(2)
2501 maxproc
2503 the maximum number of simultaneous processes for this
2504 user id
2505 maxthread
2507 the maximum number of simultaneous threads (lightweight
2508 processes) for this user id
2509 threads
2511 the maximum number of threads for this process
2512 sbsize the maximum size of socket buffer usage for this user
2514 swapsize
2516 the maximum amount of swap space reserved or used for
2517 this user
2518 maxlocks
2520 the maximum number of locks for this user
2521 posixlocks
2523 the maximum number of POSIX advisory locks for this user
2524 maxsignal
2526 the maximum number of pending signals for this user
2527 maxmessage
2529 the maximum number of bytes in POSIX mqueues for this
2530 user
2531 maxnice
2533 the maximum nice priority the user is allowed to raise
2534 mapped from [19...-20] to [0...39] for this user
2535 maxrtprio
2537 the maximum realtime priority for this user maxrttime
2538 the timeout for RT tasks in microseconds for this user.
2539 maximum-use may be given as a (floating point or integer) num‐
2541 ber followed by a scale factor. For all limits other than
2542 cputime the default scale is `k' or `kilobytes' (1024 bytes); a
2543 scale factor of `m' or `megabytes' or `g' or `gigabytes' may
2544 also be used. For cputime the default scaling is `seconds',
2545 while `m' for minutes or `h' for hours, or a time of the form
2546 `mm:ss' giving minutes and seconds may be used.
2547 If maximum-use is `unlimited', then the limitation on the
2549 specified resource is removed (this is equivalent to the un‐
2550 limit builtin command).
2551 For both resource names and scale factors, unambiguous prefixes
2553 of the names suffice.
2554 log (+) Prints the watch shell variable and reports on each user indi‐
2556 cated in watch who is logged in, regardless of when they last
2557 logged in. See also watchlog.
2558 login Terminates a login shell, replacing it with an instance of
2560 /bin/login. This is one way to log off, included for compati‐
2561 bility with sh(1).
2562 logout Terminates a login shell. Especially useful if ignoreeof is
2564 set.
2565 ls-F [-switch ...] [file ...] (+)
2567 Lists files like `ls -F', but much faster. It identifies each
2568 type of special file in the listing with a special character:
2569 / Directory
2571 * Executable
2572 # Block device
2573 % Character device
2574 | Named pipe (systems with named pipes only)
2575 = Socket (systems with sockets only)
2576 @ Symbolic link (systems with symbolic links only)
2577 + Hidden directory (AIX only) or context dependent (HP/UX
2578 only)
2579 : Network special (HP/UX only)
2580 If the listlinks shell variable is set, symbolic links are
2582 identified in more detail (on only systems that have them, of
2583 course):
2584 @ Symbolic link to a non-directory
2586 > Symbolic link to a directory
2587 & Symbolic link to nowhere
2588 listlinks also slows down ls-F and causes partitions holding
2590 files pointed to by symbolic links to be mounted.
2591 If the listflags shell variable is set to `x', `a' or `A', or
2593 any combination thereof (e.g., `xA'), they are used as flags to
2594 ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com‐
2595 bination (e.g., `ls -FxA'). On machines where `ls -C' is not
2596 the default, ls-F acts like `ls -CF', unless listflags contains
2597 an `x', in which case it acts like `ls -xF'. ls-F passes its
2598 arguments to ls(1) if it is given any switches, so `alias ls
2599 ls-F' generally does the right thing.
2600 The ls-F builtin can list files using different colors depend‐
2602 ing on the filetype or extension. See the color shell variable
2603 and the LS_COLORS environment variable.
2604 migrate [-site] pid|%jobid ... (+)
2606 migrate -site (+)
2607 The first form migrates the process or job to the site speci‐
2608 fied or the default site determined by the system path. The
2609 second form is equivalent to `migrate -site $$': it migrates
2610 the current process to the specified site. Migrating the shell
2611 itself can cause unexpected behavior, because the shell does
2612 not like to lose its tty. (TCF only)
2613 newgrp [-] [group] (+)
2615 Equivalent to `exec newgrp'; see newgrp(1). Available only if
2616 the shell was so compiled; see the version shell variable.
2617 nice [+number] [command]
2619 Sets the scheduling priority for the shell to number, or, with‐
2620 out number, to 4. With command, runs command at the appropri‐
2621 ate priority. The greater the number, the less cpu the process
2622 gets. The super-user may specify negative priority by using
2623 `nice -number ...'. Command is always executed in a sub-shell,
2624 and the restrictions placed on commands in simple if statements
2625 apply.
2626 nohup [command]
2628 With command, runs command such that it will ignore hangup sig‐
2629 nals. Note that commands may set their own response to
2630 hangups, overriding nohup. Without an argument, causes the
2631 non-interactive shell only to ignore hangups for the remainder
2632 of the script. See also Signal handling and the hup builtin
2633 command.
2634 notify [%job ...]
2636 Causes the shell to notify the user asynchronously when the
2637 status of any of the specified jobs (or, without %job, the cur‐
2638 rent job) changes, instead of waiting until the next prompt as
2639 is usual. job may be a number, a string, `', `%', `+' or `-'
2640 as described under Jobs. See also the notify shell variable.
2641 onintr [-|label]
2643 Controls the action of the shell on interrupts. Without argu‐
2644 ments, restores the default action of the shell on interrupts,
2645 which is to terminate shell scripts or to return to the termi‐
2646 nal command input level. With `-', causes all interrupts to be
2647 ignored. With label, causes the shell to execute a `goto la‐
2648 bel' when an interrupt is received or a child process termi‐
2649 nates because it was interrupted.
2650 onintr is ignored if the shell is running detached and in sys‐
2652 tem startup files (see FILES), where interrupts are disabled
2653 anyway.
2654 popd [-p] [-l] [-n|-v] [+n]
2656 Without arguments, pops the directory stack and returns to the
2657 new top directory. With a number `+n', discards the n'th entry
2658 in the stack.
2659 Finally, all forms of popd print the final directory stack,
2661 just like dirs. The pushdsilent shell variable can be set to
2662 prevent this and the -p flag can be given to override pushdsi‐
2663 lent. The -l, -n and -v flags have the same effect on popd as
2664 on dirs. (+)
2665 printenv [name] (+)
2667 Prints the names and values of all environment variables or,
2668 with name, the value of the environment variable name.
2669 pushd [-p] [-l] [-n|-v] [name|+n]
2671 Without arguments, exchanges the top two elements of the direc‐
2672 tory stack. If pushdtohome is set, pushd without arguments
2673 does `pushd ~', like cd. (+) With name, pushes the current
2674 working directory onto the directory stack and changes to name.
2675 If name is `-' it is interpreted as the previous working direc‐
2676 tory (see Filename substitution). (+) If dunique is set, pushd
2677 removes any instances of name from the stack before pushing it
2678 onto the stack. (+) With a number `+n', rotates the nth ele‐
2679 ment of the directory stack around to be the top element and
2680 changes to it. If dextract is set, however, `pushd +n' ex‐
2681 tracts the nth directory, pushes it onto the top of the stack
2682 and changes to it. (+)
2683 Finally, all forms of pushd print the final directory stack,
2685 just like dirs. The pushdsilent shell variable can be set to
2686 prevent this and the -p flag can be given to override pushdsi‐
2687 lent. The -l, -n and -v flags have the same effect on pushd as
2688 on dirs. (+)
2689 rehash Causes the internal hash table of the contents of the directo‐
2691 ries in the path variable to be recomputed. This is needed if
2692 the autorehash shell variable is not set and new commands are
2693 added to directories in path while you are logged in. With au‐
2694 torehash, a new command will be found automatically, except in
2695 the special case where another command of the same name which
2696 is located in a different directory already exists in the hash
2697 table. Also flushes the cache of home directories built by
2698 tilde expansion.
2699 repeat count command
2701 The specified command, which is subject to the same restric‐
2702 tions as the command in the one line if statement above, is ex‐
2703 ecuted count times. I/O redirections occur exactly once, even
2704 if count is 0.
2705 rootnode //nodename (+)
2707 Changes the rootnode to //nodename, so that `/' will be inter‐
2708 preted as `//nodename'. (Domain/OS only)
2709 sched (+)
2711 sched [+]hh:mm command (+)
2712 sched -n (+)
2713 The first form prints the scheduled-event list. The sched
2714 shell variable may be set to define the format in which the
2715 scheduled-event list is printed. The second form adds command
2716 to the scheduled-event list. For example,
2717 > sched 11:00 echo It\'s eleven o\'clock.
2719 causes the shell to echo `It's eleven o'clock.' at 11 AM. The
2721 time may be in 12-hour AM/PM format
2722 > sched 5pm set prompt='[%h] It\'s after 5; go home: >'
2724 or may be relative to the current time:
2726 > sched +2:15 /usr/lib/uucp/uucico -r1 -sother
2728 A relative time specification may not use AM/PM format. The
2730 third form removes item n from the event list:
2731 > sched
2733 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2734 2 Wed Apr 4 17:00 set prompt=[%h] It's after 5; go
2735 home: >
2736 > sched -2
2737 > sched
2738 1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
2739 A command in the scheduled-event list is executed just before
2741 the first prompt is printed after the time when the command is
2742 scheduled. It is possible to miss the exact time when the com‐
2743 mand is to be run, but an overdue command will execute at the
2744 next prompt. A command which comes due while the shell is
2745 waiting for user input is executed immediately. However, nor‐
2746 mal operation of an already-running command will not be inter‐
2747 rupted so that a scheduled-event list element may be run.
2748 This mechanism is similar to, but not the same as, the at(1)
2750 command on some Unix systems. Its major disadvantage is that
2751 it may not run a command at exactly the specified time. Its
2752 major advantage is that because sched runs directly from the
2753 shell, it has access to shell variables and other structures.
2754 This provides a mechanism for changing one's working environ‐
2755 ment based on the time of day.
2756 set
2758 set name ...
2759 set name=word ...
2760 set [-r] [-f|-l] name=(wordlist) ... (+)
2761 set name[index]=word ...
2762 set -r (+)
2763 set -r name ... (+)
2764 set -r name=word ... (+)
2765 The first form of the command prints the value of all shell
2766 variables. Variables which contain more than a single word
2767 print as a parenthesized word list. The second form sets name
2768 to the null string. The third form sets name to the single
2769 word. The fourth form sets name to the list of words in
2770 wordlist. In all cases the value is command and filename ex‐
2771 panded. If -r is specified, the value is set read-only. If -f
2772 or -l are specified, set only unique words keeping their order.
2773 -f prefers the first occurrence of a word, and -l the last.
2774 The fifth form sets the index'th component of name to word;
2775 this component must already exist. The sixth form lists only
2776 the names of all shell variables that are read-only. The sev‐
2777 enth form makes name read-only, whether or not it has a value.
2778 The eighth form is the same as the third form, but make name
2779 read-only at the same time.
2780 These arguments can be repeated to set and/or make read-only
2782 multiple variables in a single set command. Note, however,
2783 that variable expansion happens for all arguments before any
2784 setting occurs. Note also that `=' can be adjacent to both
2785 name and word or separated from both by whitespace, but cannot
2786 be adjacent to only one or the other. See also the unset
2787 builtin command.
2788 setenv [name [value]]
2790 Without arguments, prints the names and values of all environ‐
2791 ment variables. Given name, sets the environment variable name
2792 to value or, without value, to the null string.
2793 setpath path (+)
2795 Equivalent to setpath(1). (Mach only)
2796 setspath LOCAL|site|cpu ... (+)
2798 Sets the system execution path. (TCF only)
2799 settc cap value (+)
2801 Tells the shell to believe that the terminal capability cap (as
2802 defined in termcap(5)) has the value value. No sanity checking
2803 is done. Concept terminal users may have to `settc xn no' to
2804 get proper wrapping at the rightmost column.
2805 setty [-d|-q|-x] [-a] [[+|-]mode] (+)
2807 Controls which tty modes (see Terminal management) the shell
2808 does not allow to change. -d, -q or -x tells setty to act on
2809 the `edit', `quote' or `execute' set of tty modes respectively;
2810 without -d, -q or -x, `execute' is used.
2811 Without other arguments, setty lists the modes in the chosen
2813 set which are fixed on (`+mode') or off (`-mode'). The avail‐
2814 able modes, and thus the display, vary from system to system.
2815 With -a, lists all tty modes in the chosen set whether or not
2816 they are fixed. With +mode, -mode or mode, fixes mode on or
2817 off or removes control from mode in the chosen set. For exam‐
2818 ple, `setty +echok echoe' fixes `echok' mode on and allows com‐
2819 mands to turn `echoe' mode on or off, both when the shell is
2820 executing commands.
2821 setxvers [string] (+)
2823 Set the experimental version prefix to string, or removes it if
2824 string is omitted. (TCF only)
2825 shift [variable]
2827 Without arguments, discards argv[1] and shifts the members of
2828 argv to the left. It is an error for argv not to be set or to
2829 have less than one word as value. With variable, performs the
2830 same function on variable.
2831 source [-h] name [args ...]
2833 The shell reads and executes commands from name. The commands
2834 are not placed on the history list. If any args are given,
2835 they are placed in argv. (+) source commands may be nested; if
2836 they are nested too deeply the shell may run out of file de‐
2837 scriptors. An error in a source at any level terminates all
2838 nested source commands. With -h, commands are placed on the
2839 history list instead of being executed, much like `history -L'.
2840 stop %job|pid ...
2842 Stops the specified jobs or processes which are executing in
2843 the background. job may be a number, a string, `', `%', `+' or
2844 `-' as described under Jobs. There is no default job; saying
2845 just `stop' does not stop the current job.
2846 suspend Causes the shell to stop in its tracks, much as if it had been
2848 sent a stop signal with ^Z. This is most often used to stop
2849 shells started by su(1).
2850 switch (string)
2852 case str1:
2853 ...
2854 breaksw
2855 ...
2856 default:
2857 ...
2858 breaksw
2859 endsw Each case label is successively matched, against the specified
2860 string which is first command and filename expanded. The file
2861 metacharacters `*', `?' and `[...]' may be used in the case
2862 labels, which are variable expanded. If none of the labels
2863 match before a `default' label is found, then the execution be‐
2864 gins after the default label. Each case label and the default
2865 label must appear at the beginning of a line. The command
2866 breaksw causes execution to continue after the endsw. Other‐
2867 wise control may fall through case labels and default labels as
2868 in C. If no label matches and there is no default, execution
2869 continues after the endsw.
2870 telltc (+)
2872 Lists the values of all terminal capabilities (see termcap(5)).
2873 termname [terminal type] (+)
2875 Tests if terminal type (or the current value of TERM if no ter‐
2876 minal type is given) has an entry in the hosts termcap(5) or
2877 terminfo(5) database. Prints the terminal type to stdout and
2878 returns 0 if an entry is present otherwise returns 1.
2879 time [command]
2881 Executes command (which must be a simple command, not an alias,
2882 a pipeline, a command list or a parenthesized command list) and
2883 prints a time summary as described under the time variable. If
2884 necessary, an extra shell is created to print the time statis‐
2885 tic when the command completes. Without command, prints a time
2886 summary for the current shell and its children.
2887 umask [value]
2889 Sets the file creation mask to value, which is given in octal.
2890 Common values for the mask are 002, giving all access to the
2891 group and read and execute access to others, and 022, giving
2892 read and execute access to the group and others. Without
2893 value, prints the current file creation mask.
2894 unalias pattern
2896 Removes all aliases whose names match pattern. `unalias *'
2897 thus removes all aliases. It is not an error for nothing to be
2898 unaliased.
2899 uncomplete pattern (+)
2901 Removes all completions whose names match pattern. `uncomplete
2902 *' thus removes all completions. It is not an error for noth‐
2903 ing to be uncompleted.
2904 unhash Disables use of the internal hash table to speed location of
2906 executed programs.
2907 universe universe (+)
2909 Sets the universe to universe. (Masscomp/RTU only)
2910 unlimit [-hf] [resource]
2912 Removes the limitation on resource or, if no resource is speci‐
2913 fied, all resource limitations. With -h, the corresponding
2914 hard limits are removed. Only the super-user may do this.
2915 Note that unlimit may not exit successful, since most systems
2916 do not allow descriptors to be unlimited. With -f errors are
2917 ignored.
2918 unset pattern
2920 Removes all variables whose names match pattern, unless they
2921 are read-only. `unset *' thus removes all variables unless
2922 they are read-only; this is a bad idea. It is not an error for
2923 nothing to be unset.
2924 unsetenv pattern
2926 Removes all environment variables whose names match pattern.
2927 `unsetenv *' thus removes all environment variables; this is a
2928 bad idea. It is not an error for nothing to be unsetenved.
2929 ver [systype [command]] (+)
2931 Without arguments, prints SYSTYPE. With systype, sets SYSTYPE
2932 to systype. With systype and command, executes command under
2933 systype. systype may be `bsd4.3' or `sys5.3'. (Domain/OS
2934 only)
2935 wait The shell waits for all background jobs. If the shell is in‐
2937 teractive, an interrupt will disrupt the wait and cause the
2938 shell to print the names and job numbers of all outstanding
2939 jobs.
2940 warp universe (+)
2942 Sets the universe to universe. (Convex/OS only)
2943 watchlog (+)
2945 An alternate name for the log builtin command (q.v.). Avail‐
2946 able only if the shell was so compiled; see the version shell
2947 variable.
2948 where command (+)
2950 Reports all known instances of command, including aliases,
2951 builtins and executables in path.
2952 which command (+)
2954 Displays the command that will be executed by the shell after
2955 substitutions, path searching, etc. The builtin command is
2956 just like which(1), but it correctly reports tcsh aliases and
2957 builtins and is 10 to 100 times faster. See also the which-
2958 command editor command.
2959 while (expr)
2961 ...
2962 end Executes the commands between the while and the matching end
2963 while expr (an expression, as described under Expressions)
2964 evaluates non-zero. while and end must appear alone on their
2965 input lines. break and continue may be used to terminate or
2966 continue the loop prematurely. If the input is a terminal, the
2967 user is prompted the first time through the loop as with fore‐
2968 ach.
2969 Special aliases (+)
2971 If set, each of these aliases executes automatically at the indicated
2972 time. They are all initially undefined.
2973 beepcmd Runs when the shell wants to ring the terminal bell.
2975 cwdcmd Runs after every change of working directory. For example, if
2977 the user is working on an X window system using xterm(1) and a
2978 re-parenting window manager that supports title bars such as
2979 twm(1) and does
2980 > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd ^G"'
2982 then the shell will change the title of the running xterm(1) to
2984 be the name of the host, a colon, and the full current working
2985 directory. A fancier way to do that is
2986 > alias cwdcmd 'echo -n
2988 "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'
2989 This will put the hostname and working directory on the title
2991 bar but only the hostname in the icon manager menu.
2992 Note that putting a cd, pushd or popd in cwdcmd may cause an
2994 infinite loop. It is the author's opinion that anyone doing so
2995 will get what they deserve.
2996 jobcmd Runs before each command gets executed, or when the command
2998 changes state. This is similar to postcmd, but it does not
2999 print builtins.
3000 > alias jobcmd 'echo -n "^[]2\;\!#:q^G"'
3002 then executing vi foo.c will put the command string in the
3004 xterm title bar.
3005 helpcommand
3007 Invoked by the run-help editor command. The command name for
3008 which help is sought is passed as sole argument. For example,
3009 if one does
3010 > alias helpcommand '\!:1 --help'
3012 then the help display of the command itself will be invoked,
3014 using the GNU help calling convention. Currently there is no
3015 easy way to account for various calling conventions (e.g., the
3016 customary Unix `-h'), except by using a table of many commands.
3017 periodic
3019 Runs every tperiod minutes. This provides a convenient means
3020 for checking on common but infrequent changes such as new mail.
3021 For example, if one does
3022 > set tperiod = 30
3024 > alias periodic checknews
3025 then the checknews(1) program runs every 30 minutes. If peri‐
3027 odic is set but tperiod is unset or set to 0, periodic behaves
3028 like precmd.
3029 precmd Runs just before each prompt is printed. For example, if one
3031 does
3032 > alias precmd date
3034 then date(1) runs just before the shell prompts for each com‐
3036 mand. There are no limits on what precmd can be set to do, but
3037 discretion should be used.
3038 postcmd Runs before each command gets executed.
3040 > alias postcmd 'echo -n "^[]2\;\!#:q^G"'
3042 then executing vi foo.c will put the command string in the
3044 xterm title bar.
3045 shell Specifies the interpreter for executable scripts which do not
3047 themselves specify an interpreter. The first word should be a
3048 full path name to the desired interpreter (e.g., `/bin/csh' or
3049 `/usr/local/bin/tcsh').
3050 Special shell variables
3052 The variables described in this section have special meaning to the
3053 shell.
3054 The shell sets addsuffix, argv, autologout, csubstnonl, command,
3056 echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
3057 prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
3058 at startup; they do not change thereafter unless changed by the user.
3059 The shell updates cwd, dirstack, owd and status when necessary, and
3060 sets logout on logout.
3061 The shell synchronizes group, home, path, shlvl, term and user with the
3063 environment variables of the same names: whenever the environment vari‐
3064 able changes the shell changes the corresponding shell variable to
3065 match (unless the shell variable is read-only) and vice versa. Note
3066 that although cwd and PWD have identical meanings, they are not syn‐
3067 chronized in this manner, and that the shell automatically converts be‐
3068 tween the different formats of path and PATH.
3069 addsuffix (+)
3071 If set, filename completion adds `/' to the end of directories
3072 and a space to the end of normal files when they are matched
3073 exactly. Set by default.
3074 afsuser (+)
3076 If set, autologout's autolock feature uses its value instead of
3077 the local username for kerberos authentication.
3078 ampm (+)
3080 If set, all times are shown in 12-hour AM/PM format.
3081 anyerror (+)
3083 This variable selects what is propagated to the value of the
3084 status variable. For more information see the description of
3085 the status variable below.
3086 argv The arguments to the shell. Positional parameters are taken
3088 from argv, i.e., `$1' is replaced by `$argv[1]', etc. Set by
3089 default, but usually empty in interactive shells.
3090 autocorrect (+)
3092 If set, the spell-word editor command is invoked automatically
3093 before each completion attempt.
3094 autoexpand (+)
3096 If set, the expand-history editor command is invoked automati‐
3097 cally before each completion attempt. If this is set to only‐
3098 history, then only history will be expanded and a second com‐
3099 pletion will expand filenames.
3100 autolist (+)
3102 If set, possibilities are listed after an ambiguous completion.
3103 If set to `ambiguous', possibilities are listed only when no
3104 new characters are added by completion.
3105 autologout (+)
3107 The first word is the number of minutes of inactivity before
3108 automatic logout. The optional second word is the number of
3109 minutes of inactivity before automatic locking. When the shell
3110 automatically logs out, it prints `auto-logout', sets the vari‐
3111 able logout to `automatic' and exits. When the shell automati‐
3112 cally locks, the user is required to enter his password to con‐
3113 tinue working. Five incorrect attempts result in automatic lo‐
3114 gout. Set to `60' (automatic logout after 60 minutes, and no
3115 locking) by default in login and superuser shells, but not if
3116 the shell thinks it is running under a window system (i.e., the
3117 DISPLAY environment variable is set), the tty is a pseudo-tty
3118 (pty) or the shell was not so compiled (see the version shell
3119 variable). Unset or set to `0' to disable automatic logout.
3120 See also the afsuser and logout shell variables.
3121 autorehash (+)
3123 If set, the internal hash table of the contents of the directo‐
3124 ries in the path variable will be recomputed if a command is
3125 not found in the hash table. In addition, the list of avail‐
3126 able commands will be rebuilt for each command completion or
3127 spelling correction attempt if set to `complete' or `correct'
3128 respectively; if set to `always', this will be done for both
3129 cases.
3130 backslash_quote (+)
3132 If set, backslashes (`\') always quote `\', `'', and `"'. This
3133 may make complex quoting tasks easier, but it can cause syntax
3134 errors in csh(1) scripts.
3135 catalog The file name of the message catalog. If set, tcsh use
3137 `tcsh.${catalog}' as a message catalog instead of default
3138 `tcsh'.
3139 cdpath A list of directories in which cd should search for subdirecto‐
3141 ries if they aren't found in the current directory.
3142 cdtohome (+)
3144 If not set, cd requires a directory name, and will not go to
3145 the home directory if it's omitted. This is set by default.
3146 color If set, it enables color display for the builtin ls-F and it
3148 passes --color=auto to ls. Alternatively, it can be set to
3149 only ls-F or only ls to enable color to only one command. Set‐
3150 ting it to nothing is equivalent to setting it to (ls-F ls).
3151 colorcat
3153 If set, it enables color escape sequence for NLS message files.
3154 And display colorful NLS messages.
3155 command (+)
3157 If set, the command which was passed to the shell with the -c
3158 flag (q.v.).
3159 compat_expr (+)
3161 If set, the shell will evaluate expressions right to left, like
3162 the original csh.
3163 complete (+)
3165 If set to `igncase', the completion becomes case insensitive.
3166 If set to `enhance', completion ignores case and considers hy‐
3167 phens and underscores to be equivalent; it will also treat pe‐
3168 riods, hyphens and underscores (`.', `-' and `_') as word sepa‐
3169 rators. If set to `Enhance', completion matches uppercase and
3170 underscore characters explicitly and matches lowercase and hy‐
3171 phens in a case-insensitive manner; it will treat periods, hy‐
3172 phens and underscores as word separators.
3173 continue (+)
3175 If set to a list of commands, the shell will continue the
3176 listed commands, instead of starting a new one.
3177 continue_args (+)
3179 Same as continue, but the shell will execute:
3180 echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>
3182 correct (+)
3184 If set to `cmd', commands are automatically spelling-corrected.
3185 If set to `complete', commands are automatically completed. If
3186 set to `all', the entire command line is corrected.
3187 csubstnonl (+)
3189 If set, newlines and carriage returns in command substitution
3190 are replaced by spaces. Set by default.
3191 cwd The full pathname of the current directory. See also the
3193 dirstack and owd shell variables.
3194 dextract (+)
3196 If set, `pushd +n' extracts the nth directory from the direc‐
3197 tory stack rather than rotating it to the top.
3198 dirsfile (+)
3200 The default location in which `dirs -S' and `dirs -L' look for
3201 a history file. If unset, ~/.cshdirs is used. Because only
3202 ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
3203 should be set in ~/.tcshrc rather than ~/.login.
3204 dirstack (+)
3206 An array of all the directories on the directory stack.
3207 `$dirstack[1]' is the current working directory, `$dirstack[2]'
3208 the first directory on the stack, etc. Note that the current
3209 working directory is `$dirstack[1]' but `=0' in directory stack
3210 substitutions, etc. One can change the stack arbitrarily by
3211 setting dirstack, but the first element (the current working
3212 directory) is always correct. See also the cwd and owd shell
3213 variables.
3214 dspmbyte (+)
3216 Has an effect iff 'dspm' is listed as part of the version shell
3217 variable. If set to `euc', it enables display and editing EUC-
3218 kanji(Japanese) code. If set to `sjis', it enables display and
3219 editing Shift-JIS(Japanese) code. If set to `big5', it enables
3220 display and editing Big5(Chinese) code. If set to `utf8', it
3221 enables display and editing Utf8(Unicode) code. If set to the
3222 following format, it enables display and editing of original
3223 multi-byte code format:
3224 > set dspmbyte = 0000....(256 bytes)....0000
3226 The table requires just 256 bytes. Each character of 256 char‐
3228 acters corresponds (from left to right) to the ASCII codes
3229 0x00, 0x01, ... 0xff. Each character is set to number 0,1,2
3230 and 3. Each number has the following meaning:
3231 0 ... not used for multi-byte characters.
3232 1 ... used for the first byte of a multi-byte character.
3233 2 ... used for the second byte of a multi-byte character.
3234 3 ... used for both the first byte and second byte of a
3235 multi-byte character.
3236 Example:
3238 If set to `001322', the first character (means 0x00 of the
3239 ASCII code) and second character (means 0x01 of ASCII code) are
3240 set to `0'. Then, it is not used for multi-byte characters.
3241 The 3rd character (0x02) is set to '1', indicating that it is
3242 used for the first byte of a multi-byte character. The 4th
3243 character(0x03) is set '3'. It is used for both the first byte
3244 and the second byte of a multi-byte character. The 5th and 6th
3245 characters (0x04,0x05) are set to '2', indicating that they are
3246 used for the second byte of a multi-byte character.
3247 The GNU fileutils version of ls cannot display multi-byte file‐
3249 names without the -N ( --literal ) option. If you are using
3250 this version, set the second word of dspmbyte to "ls". If not,
3251 for example, "ls-F -l" cannot display multi-byte filenames.
3252 Note:
3254 This variable can only be used if KANJI and DSPMBYTE has been
3255 defined at compile time.
3256 dunique (+)
3258 If set, pushd removes any instances of name from the stack be‐
3259 fore pushing it onto the stack.
3260 echo If set, each command with its arguments is echoed just before
3262 it is executed. For non-builtin commands all expansions occur
3263 before echoing. Builtin commands are echoed before command and
3264 filename substitution, because these substitutions are then
3265 done selectively. Set by the -x command line option.
3266 echo_style (+)
3268 The style of the echo builtin. May be set to
3269 bsd Don't echo a newline if the first argument is `-n'; the
3271 default for csh.
3272 sysv Recognize backslashed escape sequences in echo strings.
3273 both Recognize both the `-n' flag and backslashed escape se‐
3274 quences; the default for tcsh.
3275 none Recognize neither.
3276 Set by default to the local system default. The BSD and System
3278 V options are described in the echo(1) man pages on the appro‐
3279 priate systems.
3280 edit (+)
3282 If set, the command-line editor is used. Set by default in in‐
3283 teractive shells.
3284 editors (+)
3286 A list of command names for the run-fg-editor editor command to
3287 match. If not set, the EDITOR (`ed' if unset) and VISUAL (`vi'
3288 if unset) environment variables will be used instead.
3289 ellipsis (+)
3291 If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
3292 shell variable) indicate skipped directories with an ellipsis
3293 (`...') instead of `/<skipped>'.
3294 euid (+)
3296 The user's effective user ID.
3297 euser (+)
3299 The first matching passwd entry name corresponding to the ef‐
3300 fective user ID.
3301 fignore (+)
3303 Lists file name suffixes to be ignored by completion.
3304 filec In tcsh, completion is always used and this variable is ignored
3306 by default. If edit is unset, then the traditional csh comple‐
3307 tion is used. If set in csh, filename completion is used.
3308 gid (+) The user's real group ID.
3310 globdot (+)
3312 If set, wild-card glob patterns will match files and directo‐
3313 ries beginning with `.' except for `.' and `..'
3314 globstar (+)
3316 If set, the `**' and `***' file glob patterns will match any
3317 string of characters including `/' traversing any existing sub-
3318 directories. (e.g. `ls **.c' will list all the .c files in
3319 the current directory tree). If used by itself, it will match
3320 zero or more sub-directories (e.g. `ls /usr/include/**/time.h'
3321 will list any file named `time.h' in the /usr/include directory
3322 tree; whereas `ls /usr/include/**time.h' will match any file in
3323 the /usr/include directory tree ending in `time.h'). To pre‐
3324 vent problems with recursion, the `**' glob-pattern will not
3325 descend into a symbolic link containing a directory. To over‐
3326 ride this, use `***'
3327 group (+)
3329 The user's group name.
3330 highlight
3332 If set, the incremental search match (in i-search-back and i-
3333 search-fwd) and the region between the mark and the cursor are
3334 highlighted in reverse video.
3335 Highlighting requires more frequent terminal writes, which in‐
3337 troduces extra overhead. If you care about terminal perfor‐
3338 mance, you may want to leave this unset.
3339 histchars
3341 A string value determining the characters used in History sub‐
3342 stitution (q.v.). The first character of its value is used as
3343 the history substitution character, replacing the default char‐
3344 acter `!'. The second character of its value replaces the
3345 character `^' in quick substitutions.
3346 histdup (+)
3348 Controls handling of duplicate entries in the history list. If
3349 set to `all' only unique history events are entered in the his‐
3350 tory list. If set to `prev' and the last history event is the
3351 same as the current command, then the current command is not
3352 entered in the history. If set to `erase' and the same event
3353 is found in the history list, that old event gets erased and
3354 the current one gets inserted. Note that the `prev' and `all'
3355 options renumber history events so there are no gaps.
3356 histfile (+)
3358 The default location in which `history -S' and `history -L'
3359 look for a history file. If unset, ~/.history is used. hist‐
3360 file is useful when sharing the same home directory between
3361 different machines, or when saving separate histories on dif‐
3362 ferent terminals. Because only ~/.tcshrc is normally sourced
3363 before ~/.history, histfile should be set in ~/.tcshrc rather
3364 than ~/.login.
3365 histlit (+)
3367 If set, builtin and editor commands and the savehist mechanism
3368 use the literal (unexpanded) form of lines in the history list.
3369 See also the toggle-literal-history editor command.
3370 history The first word indicates the number of history events to save.
3372 The optional second word (+) indicates the format in which his‐
3373 tory is printed; if not given, `%h\t%T\t%R\n' is used. The
3374 format sequences are described below under prompt; note the
3375 variable meaning of `%R'. Set to `100' by default.
3376 home Initialized to the home directory of the invoker. The filename
3378 expansion of `~' refers to this variable.
3379 ignoreeof
3381 If set to the empty string or `0' and the input device is a
3382 terminal, the end-of-file command (usually generated by the
3383 user by typing `^D' on an empty line) causes the shell to print
3384 `Use "exit" to leave tcsh.' instead of exiting. This prevents
3385 the shell from accidentally being killed. Historically this
3386 setting exited after 26 successive EOF's to avoid infinite
3387 loops. If set to a number n, the shell ignores n - 1 consecu‐
3388 tive end-of-files and exits on the nth. (+) If unset, `1' is
3389 used, i.e., the shell exits on a single `^D'.
3390 implicitcd (+)
3392 If set, the shell treats a directory name typed as a command as
3393 though it were a request to change to that directory. If set
3394 to verbose, the change of directory is echoed to the standard
3395 output. This behavior is inhibited in non-interactive shell
3396 scripts, or for command strings with more than one word.
3397 Changing directory takes precedence over executing a like-named
3398 command, but it is done after alias substitutions. Tilde and
3399 variable expansions work as expected.
3400 inputmode (+)
3402 If set to `insert' or `overwrite', puts the editor into that
3403 input mode at the beginning of each line.
3404 killdup (+)
3406 Controls handling of duplicate entries in the kill ring. If
3407 set to `all' only unique strings are entered in the kill ring.
3408 If set to `prev' and the last killed string is the same as the
3409 current killed string, then the current string is not entered
3410 in the ring. If set to `erase' and the same string is found in
3411 the kill ring, the old string is erased and the current one is
3412 inserted.
3413 killring (+)
3415 Indicates the number of killed strings to keep in memory. Set
3416 to `30' by default. If unset or set to less than `2', the
3417 shell will only keep the most recently killed string. Strings
3418 are put in the killring by the editor commands that delete
3419 (kill) strings of text, e.g. backward-delete-word, kill-line,
3420 etc, as well as the copy-region-as-kill command. The yank edi‐
3421 tor command will yank the most recently killed string into the
3422 command-line, while yank-pop (see Editor commands) can be used
3423 to yank earlier killed strings.
3424 listflags (+)
3426 If set to `x', `a' or `A', or any combination thereof (e.g.,
3427 `xA'), they are used as flags to ls-F, making it act like `ls
3428 -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
3429 `a' shows all files (even if they start with a `.'), `A' shows
3430 all files but `.' and `..', and `x' sorts across instead of
3431 down. If the second word of listflags is set, it is used as
3432 the path to `ls(1)'.
3433 listjobs (+)
3435 If set, all jobs are listed when a job is suspended. If set to
3436 `long', the listing is in long format.
3437 listlinks (+)
3439 If set, the ls-F builtin command shows the type of file to
3440 which each symbolic link points.
3441 listmax (+)
3443 The maximum number of items which the list-choices editor com‐
3444 mand will list without asking first.
3445 listmaxrows (+)
3447 The maximum number of rows of items which the list-choices edi‐
3448 tor command will list without asking first.
3449 loginsh (+)
3451 Set by the shell if it is a login shell. Setting or unsetting
3452 it within a shell has no effect. See also shlvl.
3453 logout (+)
3455 Set by the shell to `normal' before a normal logout, `auto‐
3456 matic' before an automatic logout, and `hangup' if the shell
3457 was killed by a hangup signal (see Signal handling). See also
3458 the autologout shell variable.
3459 mail A list of files and directories to check for incoming mail, op‐
3461 tionally preceded by a numeric word. Before each prompt, if 10
3462 minutes have passed since the last check, the shell checks each
3463 file and says `You have new mail.' (or, if mail contains multi‐
3464 ple files, `You have new mail in name.') if the filesize is
3465 greater than zero in size and has a modification time greater
3466 than its access time.
3467 If you are in a login shell, then no mail file is reported un‐
3469 less it has been modified after the time the shell has started
3470 up, to prevent redundant notifications. Most login programs
3471 will tell you whether or not you have mail when you log in.
3472 If a file specified in mail is a directory, the shell will
3474 count each file within that directory as a separate message,
3475 and will report `You have n mails.' or `You have n mails in
3476 name.' as appropriate. This functionality is provided primar‐
3477 ily for those systems which store mail in this manner, such as
3478 the Andrew Mail System.
3479 If the first word of mail is numeric it is taken as a different
3481 mail checking interval, in seconds.
3482 Under very rare circumstances, the shell may report `You have
3484 mail.' instead of `You have new mail.'
3485 matchbeep (+)
3487 If set to `never', completion never beeps. If set to `no‐
3488 match', it beeps only when there is no match. If set to `am‐
3489 biguous', it beeps when there are multiple matches. If set to
3490 `notunique', it beeps when there is one exact and other longer
3491 matches. If unset, `ambiguous' is used.
3492 nobeep (+)
3494 If set, beeping is completely disabled. See also visiblebell.
3495 noclobber
3497 If set, restrictions are placed on output redirection to insure
3498 that files are not accidentally destroyed and that `>>' redi‐
3499 rections refer to existing files, as described in the In‐
3500 put/output section.
3501 noding If set, disable the printing of `DING!' in the prompt time
3503 specifiers at the change of hour.
3504 noglob If set, Filename substitution and Directory stack substitution
3506 (q.v.) are inhibited. This is most useful in shell scripts
3507 which do not deal with filenames, or after a list of filenames
3508 has been obtained and further expansions are not desirable.
3509 nokanji (+)
3511 If set and the shell supports Kanji (see the version shell
3512 variable), it is disabled so that the meta key can be used.
3513 nonomatch
3515 If set, a Filename substitution or Directory stack substitution
3516 (q.v.) which does not match any existing files is left un‐
3517 touched rather than causing an error. It is still an error for
3518 the substitution to be malformed, e.g., `echo [' still gives an
3519 error.
3520 nostat (+)
3522 A list of directories (or glob-patterns which match directo‐
3523 ries; see Filename substitution) that should not be stat(2)ed
3524 during a completion operation. This is usually used to exclude
3525 directories which take too much time to stat(2), for example
3526 /afs.
3527 notify If set, the shell announces job completions asynchronously.
3529 The default is to present job completions just before printing
3530 a prompt.
3531 oid (+) The user's real organization ID. (Domain/OS only)
3533 owd (+) The old working directory, equivalent to the `-' used by cd and
3535 pushd. See also the cwd and dirstack shell variables.
3536 padhour If set, enable the printing of padding '0' for hours, in 24 and
3538 12 hour formats. E.G.: 07:45:42 vs. 7:45:42.
3539 parseoctal
3541 To retain compatibily with older versions numeric variables
3542 starting with 0 are not interpreted as octal. Setting this
3543 variable enables proper octal parsing.
3544 path A list of directories in which to look for executable commands.
3546 A null word specifies the current directory. If there is no
3547 path variable then only full path names will execute. path is
3548 set by the shell at startup from the PATH environment variable
3549 or, if PATH does not exist, to a system-dependent default some‐
3550 thing like `(/usr/local/bin /usr/bsd /bin /usr/bin .)'. The
3551 shell may put `.' first or last in path or omit it entirely de‐
3552 pending on how it was compiled; see the version shell variable.
3553 A shell which is given neither the -c nor the -t option hashes
3554 the contents of the directories in path after reading ~/.tcshrc
3555 and each time path is reset. If one adds a new command to a
3556 directory in path while the shell is active, one may need to do
3557 a rehash for the shell to find it.
3558 printexitvalue (+)
3560 If set and an interactive program exits with a non-zero status,
3561 the shell prints `Exit status'.
3562 prompt The string which is printed before reading each command from
3564 the terminal. prompt may include any of the following format‐
3565 ting sequences (+), which are replaced by the given informa‐
3566 tion:
3567 %/ The current working directory.
3569 %~ The current working directory, but with one's home direc‐
3570 tory represented by `~' and other users' home directories
3571 represented by `~user' as per Filename substitution.
3572 `~user' substitution happens only if the shell has already
3573 used `~user' in a pathname in the current session.
3574 %c[[0]n], %.[[0]n]
3575 The trailing component of the current working directory, or
3576 n trailing components if a digit n is given. If n begins
3577 with `0', the number of skipped components precede the
3578 trailing component(s) in the format `/<skipped>trailing'.
3579 If the ellipsis shell variable is set, skipped components
3580 are represented by an ellipsis so the whole becomes
3581 `...trailing'. `~' substitution is done as in `%~' above,
3582 but the `~' component is ignored when counting trailing
3583 components.
3584 %C Like %c, but without `~' substitution.
3585 %h, %!, !
3586 The current history event number.
3587 %M The full hostname.
3588 %m The hostname up to the first `.'.
3589 %S (%s)
3590 Start (stop) standout mode.
3591 %B (%b)
3592 Start (stop) boldfacing mode.
3593 %U (%u)
3594 Start (stop) underline mode.
3595 %t, %@
3596 The time of day in 12-hour AM/PM format.
3597 %T Like `%t', but in 24-hour format (but see the ampm shell
3598 variable).
3599 %p The `precise' time of day in 12-hour AM/PM format, with
3600 seconds.
3601 %P Like `%p', but in 24-hour format (but see the ampm shell
3602 variable).
3603 \c c is parsed as in bindkey.
3604 ^c c is parsed as in bindkey.
3605 %% A single `%'.
3606 %n The user name.
3607 %N The effective user name.
3608 %j The number of jobs.
3609 %d The weekday in `Day' format.
3610 %D The day in `dd' format.
3611 %w The month in `Mon' format.
3612 %W The month in `mm' format.
3613 %y The year in `yy' format.
3614 %Y The year in `yyyy' format.
3615 %l The shell's tty.
3616 %L Clears from the end of the prompt to end of the display or
3617 the end of the line.
3618 %$ Expands the shell or environment variable name immediately
3619 after the `$'.
3620 %# `>' (or the first character of the promptchars shell vari‐
3621 able) for normal users, `#' (or the second character of
3622 promptchars) for the superuser.
3623 %{string%}
3624 Includes string as a literal escape sequence. It should be
3625 used only to change terminal attributes and should not move
3626 the cursor location. This cannot be the last sequence in
3627 prompt.
3628 %? The return code of the command executed just before the
3629 prompt.
3630 %R In prompt2, the status of the parser. In prompt3, the cor‐
3631 rected string. In history, the history string.
3632 `%B', `%S', `%U' and `%{string%}' are available in only eight-
3634 bit-clean shells; see the version shell variable.
3635 The bold, standout and underline sequences are often used to
3637 distinguish a superuser shell. For example,
3638 > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
3640 tut [37] [2:54pm] [/usr/accts/sys] you rang? _
3641 If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
3643 set, then print `DING!' on the change of hour (i.e, `:00' min‐
3644 utes) instead of the actual time.
3645 Set by default to `%# ' in interactive shells.
3647 prompt2 (+)
3649 The string with which to prompt in while and foreach loops and
3650 after lines ending in `\'. The same format sequences may be
3651 used as in prompt (q.v.); note the variable meaning of `%R'.
3652 Set by default to `%R? ' in interactive shells.
3653 prompt3 (+)
3655 The string with which to prompt when confirming automatic
3656 spelling correction. The same format sequences may be used as
3657 in prompt (q.v.); note the variable meaning of `%R'. Set by
3658 default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.
3659 promptchars (+)
3661 If set (to a two-character string), the `%#' formatting se‐
3662 quence in the prompt shell variable is replaced with the first
3663 character for normal users and the second character for the su‐
3664 peruser.
3665 pushdtohome (+)
3667 If set, pushd without arguments does `pushd ~', like cd.
3668 pushdsilent (+)
3670 If set, pushd and popd do not print the directory stack.
3671 recexact (+)
3673 If set, completion completes on an exact match even if a longer
3674 match is possible.
3675 recognize_only_executables (+)
3677 If set, command listing displays only files in the path that
3678 are executable. Slow.
3679 rmstar (+)
3681 If set, the user is prompted before `rm *' is executed.
3682 rprompt (+)
3684 The string to print on the right-hand side of the screen (after
3685 the command input) when the prompt is being displayed on the
3686 left. It recognizes the same formatting characters as prompt.
3687 It will automatically disappear and reappear as necessary, to
3688 ensure that command input isn't obscured, and will appear only
3689 if the prompt, command input, and itself will fit together on
3690 the first line. If edit isn't set, then rprompt will be
3691 printed after the prompt and before the command input.
3692 savedirs (+)
3694 If set, the shell does `dirs -S' before exiting. If the first
3695 word is set to a number, at most that many directory stack en‐
3696 tries are saved.
3697 savehist
3699 If set, the shell does `history -S' before exiting. If the
3700 first word is set to a number, at most that many lines are
3701 saved. (The number should be less than or equal to the number
3702 history entries; if it is set to greater than the number of
3703 history settings, only history entries will be saved) If the
3704 second word is set to `merge', the history list is merged with
3705 the existing history file instead of replacing it (if there is
3706 one) and sorted by time stamp and the most recent events are
3707 retained. If the second word of savehist is `merge' and the
3708 third word is set to `lock', the history file update will be
3709 serialized with other shell sessions that would possibly like
3710 to merge history at exactly the same time. (+)
3711 sched (+)
3713 The format in which the sched builtin command prints scheduled
3714 events; if not given, `%h\t%T\t%R\n' is used. The format se‐
3715 quences are described above under prompt; note the variable
3716 meaning of `%R'.
3717 shell The file in which the shell resides. This is used in forking
3719 shells to interpret files which have execute bits set, but
3720 which are not executable by the system. (See the description
3721 of Builtin and non-builtin command execution.) Initialized to
3722 the (system-dependent) home of the shell.
3723 shlvl (+)
3725 The number of nested shells. Reset to 1 in login shells. See
3726 also loginsh.
3727 status The exit status from the last command or backquote expansion,
3729 or any command in a pipeline is propagated to status. (This is
3730 also the default csh behavior.) This default does not match
3731 what POSIX mandates (to return the status of the last command
3732 only). To match the POSIX behavior, you need to unset anyerror.
3733 If the anyerror variable is unset, the exit status of a pipe‐
3735 line is determined only from the last command in the pipeline,
3736 and the exit status of a backquote expansion is not propagated
3737 to status.
3738 If a command terminated abnormally, then 0200 is added to the
3740 status. Builtin commands which fail return exit status `1',
3741 all other builtin commands return status `0'.
3742 symlinks (+)
3744 Can be set to several different values to control symbolic link
3745 (`symlink') resolution:
3746 If set to `chase', whenever the current directory changes to a
3748 directory containing a symbolic link, it is expanded to the
3749 real name of the directory to which the link points. This does
3750 not work for the user's home directory; this is a bug.
3751 If set to `ignore', the shell tries to construct a current di‐
3753 rectory relative to the current directory before the link was
3754 crossed. This means that cding through a symbolic link and
3755 then `cd ..'ing returns one to the original directory. This
3756 affects only builtin commands and filename completion.
3757 If set to `expand', the shell tries to fix symbolic links by
3759 actually expanding arguments which look like path names. This
3760 affects any command, not just builtins. Unfortunately, this
3761 does not work for hard-to-recognize filenames, such as those
3762 embedded in command options. Expansion may be prevented by
3763 quoting. While this setting is usually the most convenient, it
3764 is sometimes misleading and sometimes confusing when it fails
3765 to recognize an argument which should be expanded. A compro‐
3766 mise is to use `ignore' and use the editor command normalize-
3767 path (bound by default to ^X-n) when necessary.
3768 Some examples are in order. First, let's set up some play di‐
3770 rectories:
3771 > cd /tmp
3773 > mkdir from from/src to
3774 > ln -s from/src to/dst
3775 Here's the behavior with symlinks unset,
3777 > cd /tmp/to/dst; echo $cwd
3779 /tmp/to/dst
3780 > cd ..; echo $cwd
3781 /tmp/from
3782 here's the behavior with symlinks set to `chase',
3784 > cd /tmp/to/dst; echo $cwd
3786 /tmp/from/src
3787 > cd ..; echo $cwd
3788 /tmp/from
3789 here's the behavior with symlinks set to `ignore',
3791 > cd /tmp/to/dst; echo $cwd
3793 /tmp/to/dst
3794 > cd ..; echo $cwd
3795 /tmp/to
3796 and here's the behavior with symlinks set to `expand'.
3798 > cd /tmp/to/dst; echo $cwd
3800 /tmp/to/dst
3801 > cd ..; echo $cwd
3802 /tmp/to
3803 > cd /tmp/to/dst; echo $cwd
3804 /tmp/to/dst
3805 > cd ".."; echo $cwd
3806 /tmp/from
3807 > /bin/echo ..
3808 /tmp/to
3809 > /bin/echo ".."
3810 ..
3811 Note that `expand' expansion 1) works just like `ignore' for
3813 builtins like cd, 2) is prevented by quoting, and 3) happens
3814 before filenames are passed to non-builtin commands.
3815 tcsh (+)
3817 The version number of the shell in the format `R.VV.PP', where
3818 `R' is the major release number, `VV' the current version and
3819 `PP' the patchlevel.
3820 term The terminal type. Usually set in ~/.login as described under
3822 Startup and shutdown.
3823 time If set to a number, then the time builtin (q.v.) executes auto‐
3825 matically after each command which takes more than that many
3826 CPU seconds. If there is a second word, it is used as a format
3827 string for the output of the time builtin. (u) The following
3828 sequences may be used in the format string:
3829 %U The time the process spent in user mode in cpu seconds.
3831 %S The time the process spent in kernel mode in cpu seconds.
3832 %E The elapsed (wall clock) time in seconds.
3833 %P The CPU percentage computed as (%U + %S) / %E.
3834 %W Number of times the process was swapped.
3835 %X The average amount in (shared) text space used in Kbytes.
3836 %D The average amount in (unshared) data/stack space used in
3837 Kbytes.
3838 %K The total space used (%X + %D) in Kbytes.
3839 %M The maximum memory the process had in use at any time in
3840 Kbytes.
3841 %F The number of major page faults (page needed to be brought
3842 from disk).
3843 %R The number of minor page faults.
3844 %I The number of input operations.
3845 %O The number of output operations.
3846 %r The number of socket messages received.
3847 %s The number of socket messages sent.
3848 %k The number of signals received.
3849 %w The number of voluntary context switches (waits).
3850 %c The number of involuntary context switches.
3851 Only the first four sequences are supported on systems without
3853 BSD resource limit functions. The default time format is `%Uu
3854 %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support re‐
3855 source usage reporting and `%Uu %Ss %E %P' for systems that do
3856 not.
3857 Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail‐
3859 able, but the following additional sequences are:
3860 %Y The number of system calls performed.
3862 %Z The number of pages which are zero-filled on demand.
3863 %i The number of times a process's resident set size was in‐
3864 creased by the kernel.
3865 %d The number of times a process's resident set size was de‐
3866 creased by the kernel.
3867 %l The number of read system calls performed.
3868 %m The number of write system calls performed.
3869 %p The number of reads from raw disk devices.
3870 %q The number of writes to raw disk devices.
3871 and the default time format is `%Uu %Ss %E %P %I+%Oio
3873 %Fpf+%Ww'. Note that the CPU percentage can be higher than
3874 100% on multi-processors.
3875 tperiod (+)
3877 The period, in minutes, between executions of the periodic spe‐
3878 cial alias.
3879 tty (+) The name of the tty, or empty if not attached to one.
3881 uid (+) The user's real user ID.
3883 user The user's login name.
3885 verbose If set, causes the words of each command to be printed, after
3887 history substitution (if any). Set by the -v command line op‐
3888 tion.
3889 version (+)
3891 The version ID stamp. It contains the shell's version number
3892 (see tcsh), origin, release date, vendor, operating system and
3893 machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
3894 list of options which were set at compile time. Options which
3895 are set by default in the distribution are noted.
3896 8b The shell is eight bit clean; default
3898 7b The shell is not eight bit clean
3899 wide The shell is multibyte encoding clean (like UTF-8)
3900 nls The system's NLS is used; default for systems with NLS
3901 lf Login shells execute /etc/csh.login before instead of af‐
3902 ter /etc/csh.cshrc and ~/.login before instead of after
3903 ~/.tcshrc and ~/.history.
3904 dl `.' is put last in path for security; default
3905 nd `.' is omitted from path for security
3906 vi vi(1)-style editing is the default rather than
3907 emacs(1)-style
3908 dtr Login shells drop DTR when exiting
3909 bye bye is a synonym for logout and log is an alternate name
3910 for watchlog
3911 al autologout is enabled; default
3912 kan Kanji is used if appropriate according to locale set‐
3913 tings, unless the nokanji shell variable is set
3914 sm The system's malloc(3) is used
3915 hb The `#!<program> <args>' convention is emulated when exe‐
3916 cuting shell scripts
3917 ng The newgrp builtin is available
3918 rh The shell attempts to set the REMOTEHOST environment
3919 variable
3920 afs The shell verifies your password with the kerberos server
3921 if local authentication fails. The afsuser shell vari‐
3922 able or the AFSUSER environment variable override your
3923 local username if set.
3924 An administrator may enter additional strings to indicate dif‐
3926 ferences in the local version.
3927 vimode (+)
3929 If unset, various key bindings change behavior to be more
3930 emacs(1)-style: word boundaries are determined by wordchars
3931 versus other characters.
3932 If set, various key bindings change behavior to be more
3934 vi(1)-style: word boundaries are determined by wordchars versus
3935 whitespace versus other characters; cursor behavior depends
3936 upon current vi mode (command, delete, insert, replace).
3937 This variable is unset by bindkey -e and set by bindkey -v.
3939 vimode may be explicitly set or unset by the user after those
3940 bindkey operations if required.
3941 visiblebell (+)
3943 If set, a screen flash is used rather than the audible bell.
3944 See also nobeep.
3945 watch (+)
3947 A list of user/terminal pairs to watch for logins and logouts.
3948 If either the user is `any' all terminals are watched for the
3949 given user and vice versa. Setting watch to `(any any)'
3950 watches all users and terminals. For example,
3951 set watch = (george ttyd1 any console $user any)
3953 reports activity of the user `george' on ttyd1, any user on the
3955 console, and oneself (or a trespasser) on any terminal.
3956 Logins and logouts are checked every 10 minutes by default, but
3958 the first word of watch can be set to a number to check every
3959 so many minutes. For example,
3960 set watch = (1 any any)
3962 reports any login/logout once every minute. For the impatient,
3964 the log builtin command triggers a watch report at any time.
3965 All current logins are reported (as with the log builtin) when
3966 watch is first set.
3967 The who shell variable controls the format of watch reports.
3969 who (+) The format string for watch messages. The following sequences
3971 are replaced by the given information:
3972 %n The name of the user who logged in/out.
3974 %a The observed action, i.e., `logged on', `logged off' or
3975 `replaced olduser on'.
3976 %l The terminal (tty) on which the user logged in/out.
3977 %M The full hostname of the remote host, or `local' if the lo‐
3978 gin/logout was from the local host.
3979 %m The hostname of the remote host up to the first `.'. The
3980 full name is printed if it is an IP address or an X Window
3981 System display.
3982 %M and %m are available on only systems that store the remote
3984 hostname in /etc/utmp. If unset, `%n has %a %l from %m.' is
3985 used, or `%n has %a %l.' on systems which don't store the re‐
3986 mote hostname.
3987 wordchars (+)
3989 A list of non-alphanumeric characters to be considered part of
3990 a word by the forward-word, backward-word etc., editor com‐
3991 mands. If unset, the default value is determined based on the
3992 state of vimode: if vimode is unset, `*?_-.[]~=' is used as the
3993 default; if vimode is set, `_' is used as the default.
3994
3996 AFSUSER (+)
3997 Equivalent to the afsuser shell variable.
3998 COLUMNS The number of columns in the terminal. See Terminal manage‐
4000 ment.
4001 DISPLAY Used by X Window System (see X(1)). If set, the shell does not
4003 set autologout (q.v.).
4004 EDITOR The pathname to a default editor. Used by the run-fg-editor
4006 editor command if the the editors shell variable is unset. See
4007 also the VISUAL environment variable.
4008 GROUP (+)
4010 Equivalent to the group shell variable.
4011 HOME Equivalent to the home shell variable.
4013 HOST (+)
4015 Initialized to the name of the machine on which the shell is
4016 running, as determined by the gethostname(2) system call.
4017 HOSTTYPE (+)
4019 Initialized to the type of machine on which the shell is run‐
4020 ning, as determined at compile time. This variable is obsolete
4021 and will be removed in a future version.
4022 HPATH (+)
4024 A colon-separated list of directories in which the run-help ed‐
4025 itor command looks for command documentation.
4026 LANG Gives the preferred character environment. See Native Language
4028 System support.
4029 LC_CTYPE
4031 If set, only ctype character handling is changed. See Native
4032 Language System support.
4033 LINES The number of lines in the terminal. See Terminal management.
4035 LS_COLORS
4037 The format of this variable is reminiscent of the termcap(5)
4038 file format; a colon-separated list of expressions of the form
4039 "xx=string", where "xx" is a two-character variable name. The
4040 variables with their associated defaults are:
4041 no 0 Normal (non-filename) text
4043 fi 0 Regular file
4044 di 01;34 Directory
4045 ln 01;36 Symbolic link
4046 pi 33 Named pipe (FIFO)
4047 so 01;35 Socket
4048 do 01;35 Door
4049 bd 01;33 Block device
4050 cd 01;32 Character device
4051 ex 01;32 Executable file
4052 mi (none) Missing file (defaults to fi)
4053 or (none) Orphaned symbolic link (defaults to ln)
4054 lc ^[[ Left code
4055 rc m Right code
4056 ec (none) End code (replaces lc+no+rc)
4057 You need to include only the variables you want to change from
4059 the default.
4060 File names can also be colorized based on filename extension.
4062 This is specified in the LS_COLORS variable using the syntax
4063 "*ext=string". For example, using ISO 6429 codes, to color all
4064 C-language source files blue you would specify "*.c=34". This
4065 would color all files ending in .c in blue (34) color.
4066 Control characters can be written either in C-style-escaped no‐
4068 tation, or in stty-like ^-notation. The C-style notation adds
4069 ^[ for Escape, _ for a normal space character, and ? for
4070 Delete. In addition, the ^[ escape character can be used to
4071 override the default interpretation of ^[, ^, : and =.
4072 Each file will be written as <lc> <color-code> <rc> <filename>
4074 <ec>. If the <ec> code is undefined, the sequence <lc> <no>
4075 <rc> will be used instead. This is generally more convenient
4076 to use, but less general. The left, right and end codes are
4077 provided so you don't have to type common parts over and over
4078 again and to support weird terminals; you will generally not
4079 need to change them at all unless your terminal does not use
4080 ISO 6429 color sequences but a different system.
4081 If your terminal does use ISO 6429 color codes, you can compose
4083 the type codes (i.e., all except the lc, rc, and ec codes) from
4084 numerical commands separated by semicolons. The most common
4085 commands are:
4086 0 to restore default color
4088 1 for brighter colors
4089 4 for underlined text
4090 5 for flashing text
4091 30 for black foreground
4092 31 for red foreground
4093 32 for green foreground
4094 33 for yellow (or brown) foreground
4095 34 for blue foreground
4096 35 for purple foreground
4097 36 for cyan foreground
4098 37 for white (or gray) foreground
4099 40 for black background
4100 41 for red background
4101 42 for green background
4102 43 for yellow (or brown) background
4103 44 for blue background
4104 45 for purple background
4105 46 for cyan background
4106 47 for white (or gray) background
4107 Not all commands will work on all systems or display devices.
4109 A few terminal programs do not recognize the default end code
4111 properly. If all text gets colorized after you do a directory
4112 listing, try changing the no and fi codes from 0 to the numeri‐
4113 cal codes for your standard fore- and background colors.
4114 MACHTYPE (+)
4116 The machine type (microprocessor class or machine model), as
4117 determined at compile time.
4118 NOREBIND (+)
4120 If set, printable characters are not rebound to self-insert-
4121 command. See Native Language System support.
4122 OSTYPE (+)
4124 The operating system, as determined at compile time.
4125 PATH A colon-separated list of directories in which to look for exe‐
4127 cutables. Equivalent to the path shell variable, but in a dif‐
4128 ferent format.
4129 PWD (+) Equivalent to the cwd shell variable, but not synchronized to
4131 it; updated only after an actual directory change.
4132 REMOTEHOST (+)
4134 The host from which the user has logged in remotely, if this is
4135 the case and the shell is able to determine it. Set only if
4136 the shell was so compiled; see the version shell variable.
4137 SHLVL (+)
4139 Equivalent to the shlvl shell variable.
4140 SYSTYPE (+)
4142 The current system type. (Domain/OS only)
4143 TERM Equivalent to the term shell variable.
4145 TERMCAP The terminal capability string. See Terminal management.
4147 USER Equivalent to the user shell variable.
4149 VENDOR (+)
4151 The vendor, as determined at compile time.
4152 VISUAL The pathname to a default full-screen editor. Used by the run-
4154 fg-editor editor command if the the editors shell variable is
4155 unset. See also the EDITOR environment variable.
4156
4158 /etc/csh.cshrc Read first by every shell. ConvexOS, Stellix and Intel
4159 use /etc/cshrc and NeXTs use /etc/cshrc.std. A/UX,
4160 AMIX, Cray and IRIX have no equivalent in csh(1), but
4161 read this file in tcsh anyway. Solaris 2.x does not
4162 have it either, but tcsh reads /etc/.cshrc. (+)
4163 /etc/csh.login Read by login shells after /etc/csh.cshrc. ConvexOS,
4164 Stellix and Intel use /etc/login, NeXTs use /etc/lo‐
4165 gin.std, Solaris 2.x uses /etc/.login and A/UX, AMIX,
4166 Cray and IRIX use /etc/cshrc.
4167 ~/.tcshrc (+) Read by every shell after /etc/csh.cshrc or its equiva‐
4168 lent.
4169 ~/.cshrc Read by every shell, if ~/.tcshrc doesn't exist, after
4170 /etc/csh.cshrc or its equivalent. This manual uses
4171 `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
4172 found, ~/.cshrc'.
4173 ~/.history Read by login shells after ~/.tcshrc if savehist is
4174 set, but see also histfile.
4175 ~/.login Read by login shells after ~/.tcshrc or ~/.history.
4176 The shell may be compiled to read ~/.login before in‐
4177 stead of after ~/.tcshrc and ~/.history; see the ver‐
4178 sion shell variable.
4179 ~/.cshdirs (+) Read by login shells after ~/.login if savedirs is set,
4180 but see also dirsfile.
4181 /etc/csh.logout Read by login shells at logout. ConvexOS, Stellix and
4182 Intel use /etc/logout and NeXTs use /etc/logout.std.
4183 A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
4184 but read this file in tcsh anyway. Solaris 2.x does
4185 not have it either, but tcsh reads /etc/.logout. (+)
4186 ~/.logout Read by login shells at logout after /etc/csh.logout or
4187 its equivalent.
4188 /bin/sh Used to interpret shell scripts not starting with a
4189 `#'.
4190 /tmp/sh* Temporary file for `<<'.
4191 /etc/passwd Source of home directories for `~name' substitutions.
4192 The order in which startup files are read may differ if the shell was
4194 so compiled; see Startup and shutdown and the version shell variable.
4195
4197 This manual describes tcsh as a single entity, but experienced csh(1)
4198 users will want to pay special attention to tcsh's new features.
4199 A command-line editor, which supports emacs(1)-style or vi(1)-style key
4201 bindings. See The command-line editor and Editor commands.
4202 Programmable, interactive word completion and listing. See Completion
4204 and listing and the complete and uncomplete builtin commands.
4205 Spelling correction (q.v.) of filenames, commands and variables.
4207 Editor commands (q.v.) which perform other useful functions in the mid‐
4209 dle of typed commands, including documentation lookup (run-help), quick
4210 editor restarting (run-fg-editor) and command resolution (which-com‐
4211 mand).
4212 An enhanced history mechanism. Events in the history list are time-
4214 stamped. See also the history command and its associated shell vari‐
4215 ables, the previously undocumented `#' event specifier and new modi‐
4216 fiers under History substitution, the *-history, history-search-*, i-
4217 search-*, vi-search-* and toggle-literal-history editor commands and
4218 the histlit shell variable.
4219 Enhanced directory parsing and directory stack handling. See the cd,
4221 pushd, popd and dirs commands and their associated shell variables, the
4222 description of Directory stack substitution, the dirstack, owd and sym‐
4223 links shell variables and the normalize-command and normalize-path edi‐
4224 tor commands.
4225 Negation in glob-patterns. See Filename substitution.
4227 New File inquiry operators (q.v.) and a filetest builtin which uses
4229 them.
4230 A variety of Automatic, periodic and timed events (q.v.) including
4232 scheduled events, special aliases, automatic logout and terminal lock‐
4233 ing, command timing and watching for logins and logouts.
4234 Support for the Native Language System (see Native Language System sup‐
4236 port), OS variant features (see OS variant support and the echo_style
4237 shell variable) and system-dependent file locations (see FILES).
4238 Extensive terminal-management capabilities. See Terminal management.
4240 New builtin commands including builtins, hup, ls-F, newgrp, printenv,
4242 which and where (q.v.).
4243 New variables that make useful information easily available to the
4245 shell. See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version
4246 shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
4247 environment variables.
4248 A new syntax for including useful information in the prompt string (see
4250 prompt), and special prompts for loops and spelling correction (see
4251 prompt2 and prompt3).
4252 Read-only variables. See Variable substitution.
4254
4256 When a suspended command is restarted, the shell prints the directory
4257 it started in if this is different from the current directory. This
4258 can be misleading (i.e., wrong) as the job may have changed directories
4259 internally.
4260 Shell builtin functions are not stoppable/restartable. Command se‐
4262 quences of the form `a ; b ; c' are also not handled gracefully when
4263 stopping is attempted. If you suspend `b', the shell will then immedi‐
4264 ately execute `c'. This is especially noticeable if this expansion re‐
4265 sults from an alias. It suffices to place the sequence of commands in
4266 ()'s to force it to a subshell, i.e., `( a ; b ; c )'.
4267 Control over tty output after processes are started is primitive; per‐
4269 haps this will inspire someone to work on a good virtual terminal in‐
4270 terface. In a virtual terminal interface much more interesting things
4271 could be done with output control.
4272 Alias substitution is most often used to clumsily simulate shell proce‐
4274 dures; shell procedures should be provided rather than aliases.
4275 Control structures should be parsed rather than being recognized as
4277 built-in commands. This would allow control commands to be placed any‐
4278 where, to be combined with `|', and to be used with `&' and `;' meta‐
4279 syntax.
4280 foreach doesn't ignore here documents when looking for its end.
4282 It should be possible to use the `:' modifiers on the output of command
4284 substitutions.
4285 The screen update for lines longer than the screen width is very poor
4287 if the terminal cannot move the cursor up (i.e., terminal type `dumb').
4288 HPATH and NOREBIND don't need to be environment variables.
4290 Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
4292 `~' are not negated correctly.
4293 The single-command form of if does output redirection even if the ex‐
4295 pression is false and the command is not executed.
4296 ls-F includes file identification characters when sorting filenames and
4298 does not handle control characters in filenames well. It cannot be in‐
4299 terrupted.
4300 Command substitution supports multiple commands and conditions, but not
4302 cycles or backward gotos.
4303 Report bugs at https://bugs.astron.com/, preferably with fixes. If you
4305 want to help maintain and test tcsh, add yourself to the mailing list
4306 in https://mailman.astron.com/.
4307
4309 In 1964, DEC produced the PDP-6. The PDP-10 was a later re-implementa‐
4310 tion. It was re-christened the DECsystem-10 in 1970 or so when DEC
4311 brought out the second model, the KI10.
4312 TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
4314 think tank) in 1972 as an experiment in demand-paged virtual memory op‐
4315 erating systems. They built a new pager for the DEC PDP-10 and created
4316 the OS to go with it. It was extremely successful in academia.
4317 In 1975, DEC brought out a new model of the PDP-10, the KL10; they in‐
4319 tended to have only a version of TENEX, which they had licensed from
4320 BBN, for the new box. They called their version TOPS-20 (their capi‐
4321 talization is trademarked). A lot of TOPS-10 users (`The OPerating
4322 System for PDP-10') objected; thus DEC found themselves supporting two
4323 incompatible systems on the same hardware--but then there were 6 on the
4324 PDP-11!
4325 TENEX, and TOPS-20 to version 3, had command completion via a user-
4327 code-level subroutine library called ULTCMD. With version 3, DEC moved
4328 all that capability and more into the monitor (`kernel' for you Unix
4329 types), accessed by the COMND% JSYS (`Jump to SYStem' instruction, the
4330 supervisor call mechanism [are my IBM roots also showing?]).
4331 The creator of tcsh was impressed by this feature and several others of
4333 TENEX and TOPS-20, and created a version of csh which mimicked them.
4334
4336 The system limits argument lists to ARG_MAX characters.
4337 The number of arguments to a command which involves filename expansion
4339 is limited to 1/6th the number of characters allowed in an argument
4340 list.
4341 Command substitutions may substitute no more characters than are al‐
4343 lowed in an argument list.
4344 To detect looping, the shell restricts the number of alias substitu‐
4346 tions on a single line to 20.
4347
4349 csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
4350 tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
4351 pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
4352 malloc(3), setlocale(3), tty(4), a.out(5), termcap(5), environ(7),
4353 termio(7), Introduction to the C Shell
4354
4356 This manual documents tcsh 6.22.04 (Astron) 2021-04-26.
4357
4359 William Joy
4360 Original author of csh(1)
4361 J.E. Kulp, IIASA, Laxenburg, Austria
4362 Job control and directory stack features
4363 Ken Greer, HP Labs, 1981
4364 File name completion
4365 Mike Ellis, Fairchild, 1983
4366 Command name recognition/completion
4367 Paul Placeway, Ohio State CIS Dept., 1983-1993
4368 Command line editor, prompt routines, new glob syntax and numerous
4369 fixes and speedups
4370 Karl Kleinpaste, CCI 1983-4
4371 Special aliases, directory stack extraction stuff, login/logout
4372 watch, scheduled events, and the idea of the new prompt format
4373 Rayan Zachariassen, University of Toronto, 1984
4374 ls-F and which builtins and numerous bug fixes, modifications and
4375 speedups
4376 Chris Kingsley, Caltech
4377 Fast storage allocator routines
4378 Chris Grevstad, TRW, 1987
4379 Incorporated 4.3BSD csh into tcsh
4380 Christos S. Zoulas, Cornell U. EE Dept., 1987-94
4381 Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
4382 SHORT_STRINGS support and a new version of sh.glob.c
4383 James J Dempsey, BBN, and Paul Placeway, OSU, 1988
4384 A/UX port
4385 Daniel Long, NNSC, 1988
4386 wordchars
4387 Patrick Wolfe, Kuck and Associates, Inc., 1988
4388 vi mode cleanup
4389 David C Lawrence, Rensselaer Polytechnic Institute, 1989
4390 autolist and ambiguous completion listing
4391 Alec Wolman, DEC, 1989
4392 Newlines in the prompt
4393 Matt Landau, BBN, 1989
4394 ~/.tcshrc
4395 Ray Moody, Purdue Physics, 1989
4396 Magic space bar history expansion
4397 Mordechai ????, Intel, 1989
4398 printprompt() fixes and additions
4399 Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
4400 Automatic spelling correction and prompt3
4401 Per Hedeland, Ellemtel, Sweden, 1990-
4402 Various bugfixes, improvements and manual updates
4403 Hans J. Albertsson (Sun Sweden)
4404 ampm, settc and telltc
4405 Michael Bloom
4406 Interrupt handling fixes
4407 Michael Fine, Digital Equipment Corp
4408 Extended key support
4409 Eric Schnoebelen, Convex, 1990
4410 Convex support, lots of csh bug fixes, save and restore of directory
4411 stack
4412 Ron Flax, Apple, 1990
4413 A/UX 2.0 (re)port
4414 Dan Oscarsson, LTH Sweden, 1990
4415 NLS support and simulated NLS support for non NLS sites, fixes
4416 Johan Widen, SICS Sweden, 1990
4417 shlvl, Mach support, correct-line, 8-bit printing
4418 Matt Day, Sanyo Icon, 1990
4419 POSIX termio support, SysV limit fixes
4420 Jaap Vermeulen, Sequent, 1990-91
4421 Vi mode fixes, expand-line, window change fixes, Symmetry port
4422 Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
4423 autolist beeping options, modified the history search to search for
4424 the whole string from the beginning of the line to the cursor.
4425 Scott Krotz, Motorola, 1991
4426 Minix port
4427 David Dawes, Sydney U. Australia, Physics Dept., 1991
4428 SVR4 job control fixes
4429 Jose Sousa, Interactive Systems Corp., 1991
4430 Extended vi fixes and vi delete command
4431 Marc Horowitz, MIT, 1991
4432 ANSIfication fixes, new exec hashing code, imake fixes, where
4433 Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
4434 ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
4435 and various other portability changes and bug fixes
4436 Jeff Fink, 1992
4437 complete-word-fwd and complete-word-back
4438 Harry C. Pulley, 1992
4439 Coherent port
4440 Andy Phillips, Mullard Space Science Lab U.K., 1992
4441 VMS-POSIX port
4442 Beto Appleton, IBM Corp., 1992
4443 Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
4444 SIGHUP
4445 Scott Bolte, Cray Computer Corp., 1992
4446 CSOS port
4447 Kaveh R. Ghazi, Rutgers University, 1992
4448 Tek, m88k, Titan and Masscomp ports and fixes. Added autoconf sup‐
4449 port.
4450 Mark Linderman, Cornell University, 1992
4451 OS/2 port
4452 Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
4453 Linux port
4454 Tim P. Starrin, NASA Langley Research Center Operations, 1993
4455 Read-only variables
4456 Dave Schweisguth, Yale University, 1993-4
4457 New man page and tcsh.man2html
4458 Larry Schwimmer, Stanford University, 1993
4459 AFS and HESIOD patches
4460 Luke Mewburn, RMIT University, 1994-6
4461 Enhanced directory printing in prompt, added ellipsis and rprompt.
4462 Edward Hutchins, Silicon Graphics Inc., 1996
4463 Added implicit cd.
4464 Martin Kraemer, 1997
4465 Ported to Siemens Nixdorf EBCDIC machine
4466 Amol Deshpande, Microsoft, 1997
4467 Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
4468 library and message catalog code to interface to Windows.
4469 Taga Nayuta, 1998
4470 Color ls additions.
4471
4473 Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
4474 Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
4475 the other people at Ohio State for suggestions and encouragement
4476 All the people on the net, for putting up with, reporting bugs in, and
4478 suggesting new additions to each and every version
4479 Richard M. Alderson III, for writing the `T in tcsh' section
4481Astron 6.22.04 26 Apr 2021 TCSH(1)