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1 | @ignore |
2 | This file documents the user interface to the GNU History library. | |
3 | ||
4a11f206 | 4 | Copyright (C) 1988--2014 Free Software Foundation, Inc. |
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5 | Authored by Brian Fox and Chet Ramey. |
6 | ||
7 | Permission is granted to make and distribute verbatim copies of this manual | |
8 | provided the copyright notice and this permission notice are preserved on | |
9 | all copies. | |
10 | ||
11 | Permission is granted to process this file through Tex and print the | |
12 | results, provided the printed document carries copying permission notice | |
13 | identical to this one except for the removal of this paragraph (this | |
14 | paragraph not being relevant to the printed manual). | |
15 | ||
16 | Permission is granted to copy and distribute modified versions of this | |
17 | manual under the conditions for verbatim copying, provided also that the | |
18 | GNU Copyright statement is available to the distributee, and provided that | |
19 | the entire resulting derived work is distributed under the terms of a | |
20 | permission notice identical to this one. | |
21 | ||
22 | Permission is granted to copy and distribute translations of this manual | |
23 | into another language, under the above conditions for modified versions. | |
24 | @end ignore | |
25 | ||
26 | @node Using History Interactively | |
27 | @chapter Using History Interactively | |
28 | ||
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29 | @ifclear BashFeatures |
30 | @defcodeindex bt | |
31 | @end ifclear | |
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32 | |
33 | @ifset BashFeatures | |
34 | This chapter describes how to use the @sc{gnu} History Library | |
35 | interactively, from a user's standpoint. | |
36 | It should be considered a user's guide. | |
37 | For information on using the @sc{gnu} History Library in other programs, | |
38 | see the @sc{gnu} Readline Library Manual. | |
39 | @end ifset | |
40 | @ifclear BashFeatures | |
41 | This chapter describes how to use the @sc{gnu} History Library interactively, | |
42 | from a user's standpoint. It should be considered a user's guide. For | |
43 | information on using the @sc{gnu} History Library in your own programs, | |
4a11f206 | 44 | @pxref{Programming with GNU History}. |
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45 | @end ifclear |
46 | ||
47 | @ifset BashFeatures | |
48 | @menu | |
49 | * Bash History Facilities:: How Bash lets you manipulate your command | |
50 | history. | |
51 | * Bash History Builtins:: The Bash builtin commands that manipulate | |
52 | the command history. | |
53 | * History Interaction:: What it feels like using History as a user. | |
54 | @end menu | |
55 | @end ifset | |
56 | @ifclear BashFeatures | |
57 | @menu | |
58 | * History Interaction:: What it feels like using History as a user. | |
59 | @end menu | |
60 | @end ifclear | |
61 | ||
62 | @ifset BashFeatures | |
63 | @node Bash History Facilities | |
64 | @section Bash History Facilities | |
65 | @cindex command history | |
66 | @cindex history list | |
67 | ||
68 | When the @option{-o history} option to the @code{set} builtin | |
69 | is enabled (@pxref{The Set Builtin}), | |
70 | the shell provides access to the @dfn{command history}, | |
71 | the list of commands previously typed. | |
72 | The value of the @env{HISTSIZE} shell variable is used as the | |
73 | number of commands to save in a history list. | |
74 | The text of the last @env{$HISTSIZE} | |
75 | commands (default 500) is saved. | |
76 | The shell stores each command in the history list prior to | |
77 | parameter and variable expansion | |
78 | but after history expansion is performed, subject to the | |
79 | values of the shell variables | |
80 | @env{HISTIGNORE} and @env{HISTCONTROL}. | |
81 | ||
82 | When the shell starts up, the history is initialized from the | |
83 | file named by the @env{HISTFILE} variable (default @file{~/.bash_history}). | |
84 | The file named by the value of @env{HISTFILE} is truncated, if | |
85 | necessary, to contain no more than the number of lines specified by | |
86 | the value of the @env{HISTFILESIZE} variable. | |
4a11f206 | 87 | When a shell with history enabled exits, the last |
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88 | @env{$HISTSIZE} lines are copied from the history list to the file |
89 | named by @env{$HISTFILE}. | |
90 | If the @code{histappend} shell option is set (@pxref{Bash Builtins}), | |
91 | the lines are appended to the history file, | |
92 | otherwise the history file is overwritten. | |
93 | If @env{HISTFILE} | |
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94 | is unset, or if the history file is unwritable, the history is not saved. |
95 | After saving the history, the history file is truncated | |
96 | to contain no more than @env{$HISTFILESIZE} lines. | |
97 | If @env{HISTFILESIZE} is unset, or set to null, a non-numeric value, or | |
98 | a numeric value less than zero, the history file is not truncated. | |
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99 | |
100 | If the @env{HISTTIMEFORMAT} is set, the time stamp information | |
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101 | associated with each history entry is written to the history file, |
102 | marked with the history comment character. | |
103 | When the history file is read, lines beginning with the history | |
104 | comment character followed immediately by a digit are interpreted | |
105 | as timestamps for the previous history line. | |
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106 | |
107 | The builtin command @code{fc} may be used to list or edit and re-execute | |
108 | a portion of the history list. | |
109 | The @code{history} builtin may be used to display or modify the history | |
110 | list and manipulate the history file. | |
111 | When using command-line editing, search commands | |
112 | are available in each editing mode that provide access to the | |
113 | history list (@pxref{Commands For History}). | |
114 | ||
115 | The shell allows control over which commands are saved on the history | |
116 | list. The @env{HISTCONTROL} and @env{HISTIGNORE} | |
117 | variables may be set to cause the shell to save only a subset of the | |
118 | commands entered. | |
119 | The @code{cmdhist} | |
120 | shell option, if enabled, causes the shell to attempt to save each | |
121 | line of a multi-line command in the same history entry, adding | |
122 | semicolons where necessary to preserve syntactic correctness. | |
123 | The @code{lithist} | |
124 | shell option causes the shell to save the command with embedded newlines | |
125 | instead of semicolons. | |
126 | The @code{shopt} builtin is used to set these options. | |
127 | @xref{Bash Builtins}, for a description of @code{shopt}. | |
128 | ||
129 | @node Bash History Builtins | |
130 | @section Bash History Builtins | |
131 | @cindex history builtins | |
132 | ||
133 | Bash provides two builtin commands which manipulate the | |
134 | history list and history file. | |
135 | ||
136 | @table @code | |
137 | ||
138 | @item fc | |
139 | @btindex fc | |
140 | @example | |
cc88a640 | 141 | @code{fc [-e @var{ename}] [-lnr] [@var{first}] [@var{last}]} |
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142 | @code{fc -s [@var{pat}=@var{rep}] [@var{command}]} |
143 | @end example | |
144 | ||
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145 | The first form selects a range of commands from @var{first} to |
146 | @var{last} from the history list and displays or edits and re-executes | |
147 | them. | |
148 | Both @var{first} and | |
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149 | @var{last} may be specified as a string (to locate the most recent |
150 | command beginning with that string) or as a number (an index into the | |
151 | history list, where a negative number is used as an offset from the | |
152 | current command number). If @var{last} is not specified it is set to | |
153 | @var{first}. If @var{first} is not specified it is set to the previous | |
154 | command for editing and @minus{}16 for listing. If the @option{-l} flag is | |
155 | given, the commands are listed on standard output. The @option{-n} flag | |
156 | suppresses the command numbers when listing. The @option{-r} flag | |
157 | reverses the order of the listing. Otherwise, the editor given by | |
158 | @var{ename} is invoked on a file containing those commands. If | |
159 | @var{ename} is not given, the value of the following variable expansion | |
160 | is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}. This says to use the | |
161 | value of the @env{FCEDIT} variable if set, or the value of the | |
162 | @env{EDITOR} variable if that is set, or @code{vi} if neither is set. | |
163 | When editing is complete, the edited commands are echoed and executed. | |
164 | ||
165 | In the second form, @var{command} is re-executed after each instance | |
166 | of @var{pat} in the selected command is replaced by @var{rep}. | |
4a11f206 | 167 | @var{command} is intepreted the same as @var{first} above. |
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168 | |
169 | A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so | |
170 | that typing @samp{r cc} runs the last command beginning with @code{cc} | |
171 | and typing @samp{r} re-executes the last command (@pxref{Aliases}). | |
172 | ||
173 | @item history | |
174 | @btindex history | |
175 | @example | |
176 | history [@var{n}] | |
177 | history -c | |
178 | history -d @var{offset} | |
179 | history [-anrw] [@var{filename}] | |
180 | history -ps @var{arg} | |
181 | @end example | |
182 | ||
183 | With no options, display the history list with line numbers. | |
184 | Lines prefixed with a @samp{*} have been modified. | |
185 | An argument of @var{n} lists only the last @var{n} lines. | |
186 | If the shell variable @env{HISTTIMEFORMAT} is set and not null, | |
187 | it is used as a format string for @var{strftime} to display | |
188 | the time stamp associated with each displayed history entry. | |
189 | No intervening blank is printed between the formatted time stamp | |
190 | and the history line. | |
191 | ||
192 | Options, if supplied, have the following meanings: | |
193 | ||
194 | @table @code | |
195 | @item -c | |
196 | Clear the history list. This may be combined | |
197 | with the other options to replace the history list completely. | |
198 | ||
199 | @item -d @var{offset} | |
200 | Delete the history entry at position @var{offset}. | |
201 | @var{offset} should be specified as it appears when the history is | |
202 | displayed. | |
203 | ||
204 | @item -a | |
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205 | Append the new history lines to the history file. |
206 | These are history lines entered since the beginning of the current | |
207 | Bash session, but not already appended to the history file. | |
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208 | |
209 | @item -n | |
210 | Append the history lines not already read from the history file | |
211 | to the current history list. These are lines appended to the history | |
212 | file since the beginning of the current Bash session. | |
213 | ||
214 | @item -r | |
4a11f206 | 215 | Read the history file and append its contents to |
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216 | the history list. |
217 | ||
218 | @item -w | |
4a11f206 | 219 | Write out the current history list to the history file. |
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220 | |
221 | @item -p | |
222 | Perform history substitution on the @var{arg}s and display the result | |
223 | on the standard output, without storing the results in the history list. | |
224 | ||
225 | @item -s | |
226 | The @var{arg}s are added to the end of | |
227 | the history list as a single entry. | |
228 | ||
229 | @end table | |
230 | ||
231 | When any of the @option{-w}, @option{-r}, @option{-a}, or @option{-n} options is | |
232 | used, if @var{filename} | |
233 | is given, then it is used as the history file. If not, then | |
234 | the value of the @env{HISTFILE} variable is used. | |
235 | ||
236 | @end table | |
237 | @end ifset | |
238 | ||
239 | @node History Interaction | |
240 | @section History Expansion | |
241 | @cindex history expansion | |
242 | ||
243 | The History library provides a history expansion feature that is similar | |
244 | to the history expansion provided by @code{csh}. This section | |
245 | describes the syntax used to manipulate the history information. | |
246 | ||
247 | History expansions introduce words from the history list into | |
248 | the input stream, making it easy to repeat commands, insert the | |
249 | arguments to a previous command into the current input line, or | |
250 | fix errors in previous commands quickly. | |
251 | ||
252 | History expansion takes place in two parts. The first is to determine | |
253 | which line from the history list should be used during substitution. | |
254 | The second is to select portions of that line for inclusion into the | |
255 | current one. The line selected from the history is called the | |
256 | @dfn{event}, and the portions of that line that are acted upon are | |
257 | called @dfn{words}. Various @dfn{modifiers} are available to manipulate | |
258 | the selected words. The line is broken into words in the same fashion | |
259 | that Bash does, so that several words | |
260 | surrounded by quotes are considered one word. | |
261 | History expansions are introduced by the appearance of the | |
262 | history expansion character, which is @samp{!} by default. | |
263 | @ifset BashFeatures | |
264 | Only @samp{\} and @samp{'} may be used to escape the history expansion | |
265 | character. | |
266 | @end ifset | |
267 | ||
268 | @ifset BashFeatures | |
269 | Several shell options settable with the @code{shopt} | |
270 | builtin (@pxref{Bash Builtins}) may be used to tailor | |
271 | the behavior of history expansion. If the | |
272 | @code{histverify} shell option is enabled, and Readline | |
273 | is being used, history substitutions are not immediately passed to | |
274 | the shell parser. | |
275 | Instead, the expanded line is reloaded into the Readline | |
276 | editing buffer for further modification. | |
277 | If Readline is being used, and the @code{histreedit} | |
278 | shell option is enabled, a failed history expansion will be | |
279 | reloaded into the Readline editing buffer for correction. | |
280 | The @option{-p} option to the @code{history} builtin command | |
281 | may be used to see what a history expansion will do before using it. | |
282 | The @option{-s} option to the @code{history} builtin may be used to | |
283 | add commands to the end of the history list without actually executing | |
284 | them, so that they are available for subsequent recall. | |
285 | This is most useful in conjunction with Readline. | |
286 | ||
287 | The shell allows control of the various characters used by the | |
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288 | history expansion mechanism with the @code{histchars} variable, |
289 | as explained above (@pxref{Bash Variables}). The shell uses | |
290 | the history comment character to mark history timestamps when | |
291 | writing the history file. | |
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292 | @end ifset |
293 | ||
294 | @menu | |
295 | * Event Designators:: How to specify which history line to use. | |
296 | * Word Designators:: Specifying which words are of interest. | |
297 | * Modifiers:: Modifying the results of substitution. | |
298 | @end menu | |
299 | ||
300 | @node Event Designators | |
301 | @subsection Event Designators | |
302 | @cindex event designators | |
303 | ||
304 | An event designator is a reference to a command line entry in the | |
305 | history list. | |
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306 | Unless the reference is absolute, events are relative to the current |
307 | position in the history list. | |
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308 | @cindex history events |
309 | ||
310 | @table @asis | |
311 | ||
312 | @item @code{!} | |
313 | @ifset BashFeatures | |
314 | Start a history substitution, except when followed by a space, tab, | |
315 | the end of the line, @samp{=} or @samp{(} (when the | |
316 | @code{extglob} shell option is enabled using the @code{shopt} builtin). | |
317 | @end ifset | |
318 | @ifclear BashFeatures | |
319 | Start a history substitution, except when followed by a space, tab, | |
320 | the end of the line, or @samp{=}. | |
321 | @end ifclear | |
322 | ||
323 | @item @code{!@var{n}} | |
324 | Refer to command line @var{n}. | |
325 | ||
326 | @item @code{!-@var{n}} | |
327 | Refer to the command @var{n} lines back. | |
328 | ||
329 | @item @code{!!} | |
330 | Refer to the previous command. This is a synonym for @samp{!-1}. | |
331 | ||
332 | @item @code{!@var{string}} | |
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333 | Refer to the most recent command |
334 | preceding the current position in the history list | |
335 | starting with @var{string}. | |
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336 | |
337 | @item @code{!?@var{string}[?]} | |
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338 | Refer to the most recent command |
339 | preceding the current position in the history list | |
340 | containing @var{string}. | |
341 | The trailing | |
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342 | @samp{?} may be omitted if the @var{string} is followed immediately by |
343 | a newline. | |
344 | ||
345 | @item @code{^@var{string1}^@var{string2}^} | |
346 | Quick Substitution. Repeat the last command, replacing @var{string1} | |
347 | with @var{string2}. Equivalent to | |
348 | @code{!!:s/@var{string1}/@var{string2}/}. | |
349 | ||
350 | @item @code{!#} | |
351 | The entire command line typed so far. | |
352 | ||
353 | @end table | |
354 | ||
355 | @node Word Designators | |
356 | @subsection Word Designators | |
357 | ||
358 | Word designators are used to select desired words from the event. | |
359 | A @samp{:} separates the event specification from the word designator. It | |
360 | may be omitted if the word designator begins with a @samp{^}, @samp{$}, | |
361 | @samp{*}, @samp{-}, or @samp{%}. Words are numbered from the beginning | |
362 | of the line, with the first word being denoted by 0 (zero). Words are | |
363 | inserted into the current line separated by single spaces. | |
364 | ||
365 | @need 0.75 | |
366 | For example, | |
367 | ||
368 | @table @code | |
369 | @item !! | |
370 | designates the preceding command. When you type this, the preceding | |
371 | command is repeated in toto. | |
372 | ||
373 | @item !!:$ | |
374 | designates the last argument of the preceding command. This may be | |
375 | shortened to @code{!$}. | |
376 | ||
377 | @item !fi:2 | |
378 | designates the second argument of the most recent command starting with | |
379 | the letters @code{fi}. | |
380 | @end table | |
381 | ||
382 | @need 0.75 | |
383 | Here are the word designators: | |
384 | ||
385 | @table @code | |
386 | ||
387 | @item 0 (zero) | |
388 | The @code{0}th word. For many applications, this is the command word. | |
389 | ||
390 | @item @var{n} | |
391 | The @var{n}th word. | |
392 | ||
393 | @item ^ | |
394 | The first argument; that is, word 1. | |
395 | ||
396 | @item $ | |
397 | The last argument. | |
398 | ||
399 | @item % | |
400 | The word matched by the most recent @samp{?@var{string}?} search. | |
401 | ||
402 | @item @var{x}-@var{y} | |
403 | A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}. | |
404 | ||
405 | @item * | |
406 | All of the words, except the @code{0}th. This is a synonym for @samp{1-$}. | |
407 | It is not an error to use @samp{*} if there is just one word in the event; | |
408 | the empty string is returned in that case. | |
409 | ||
410 | @item @var{x}* | |
411 | Abbreviates @samp{@var{x}-$} | |
412 | ||
413 | @item @var{x}- | |
414 | Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word. | |
415 | ||
416 | @end table | |
417 | ||
418 | If a word designator is supplied without an event specification, the | |
419 | previous command is used as the event. | |
420 | ||
421 | @node Modifiers | |
422 | @subsection Modifiers | |
423 | ||
424 | After the optional word designator, you can add a sequence of one or more | |
425 | of the following modifiers, each preceded by a @samp{:}. | |
426 | ||
427 | @table @code | |
428 | ||
429 | @item h | |
430 | Remove a trailing pathname component, leaving only the head. | |
431 | ||
432 | @item t | |
cc88a640 | 433 | Remove all leading pathname components, leaving the tail. |
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434 | |
435 | @item r | |
436 | Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving | |
437 | the basename. | |
438 | ||
439 | @item e | |
440 | Remove all but the trailing suffix. | |
441 | ||
442 | @item p | |
443 | Print the new command but do not execute it. | |
444 | ||
445 | @ifset BashFeatures | |
446 | @item q | |
447 | Quote the substituted words, escaping further substitutions. | |
448 | ||
449 | @item x | |
450 | Quote the substituted words as with @samp{q}, | |
451 | but break into words at spaces, tabs, and newlines. | |
452 | @end ifset | |
453 | ||
454 | @item s/@var{old}/@var{new}/ | |
455 | Substitute @var{new} for the first occurrence of @var{old} in the | |
456 | event line. Any delimiter may be used in place of @samp{/}. | |
457 | The delimiter may be quoted in @var{old} and @var{new} | |
458 | with a single backslash. If @samp{&} appears in @var{new}, | |
459 | it is replaced by @var{old}. A single backslash will quote | |
460 | the @samp{&}. The final delimiter is optional if it is the last | |
461 | character on the input line. | |
462 | ||
463 | @item & | |
464 | Repeat the previous substitution. | |
465 | ||
466 | @item g | |
467 | @itemx a | |
468 | Cause changes to be applied over the entire event line. Used in | |
469 | conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/}, | |
470 | or with @samp{&}. | |
471 | ||
472 | @item G | |
473 | Apply the following @samp{s} modifier once to each word in the event. | |
474 | ||
475 | @end table |