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1 | @ignore |
2 | This file documents the user interface to the GNU History library. | |
3 | ||
cb41b9e7 | 4 | Copyright (C) 1988--2018 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 | @c GDB bundling modification: |
30 | @c @ifclear BashFeatures | |
31 | @c @defcodeindex bt | |
32 | @c @end ifclear | |
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33 | |
34 | @ifset BashFeatures | |
35 | This chapter describes how to use the @sc{gnu} History Library | |
36 | interactively, from a user's standpoint. | |
37 | It should be considered a user's guide. | |
38 | For information on using the @sc{gnu} History Library in other programs, | |
39 | see the @sc{gnu} Readline Library Manual. | |
40 | @end ifset | |
41 | @ifclear BashFeatures | |
42 | This chapter describes how to use the @sc{gnu} History Library interactively, | |
43 | from a user's standpoint. It should be considered a user's guide. For | |
44 | information on using the @sc{gnu} History Library in your own programs, | |
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45 | @c GDB bundling modification: |
46 | @pxref{Programming with GNU History, , , history, GNU History Library}. | |
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47 | @end ifclear |
48 | ||
49 | @ifset BashFeatures | |
50 | @menu | |
51 | * Bash History Facilities:: How Bash lets you manipulate your command | |
52 | history. | |
53 | * Bash History Builtins:: The Bash builtin commands that manipulate | |
54 | the command history. | |
55 | * History Interaction:: What it feels like using History as a user. | |
56 | @end menu | |
57 | @end ifset | |
58 | @ifclear BashFeatures | |
59 | @menu | |
60 | * History Interaction:: What it feels like using History as a user. | |
61 | @end menu | |
62 | @end ifclear | |
63 | ||
64 | @ifset BashFeatures | |
65 | @node Bash History Facilities | |
66 | @section Bash History Facilities | |
67 | @cindex command history | |
68 | @cindex history list | |
69 | ||
70 | When the @option{-o history} option to the @code{set} builtin | |
71 | is enabled (@pxref{The Set Builtin}), | |
72 | the shell provides access to the @dfn{command history}, | |
73 | the list of commands previously typed. | |
74 | The value of the @env{HISTSIZE} shell variable is used as the | |
75 | number of commands to save in a history list. | |
76 | The text of the last @env{$HISTSIZE} | |
77 | commands (default 500) is saved. | |
78 | The shell stores each command in the history list prior to | |
79 | parameter and variable expansion | |
80 | but after history expansion is performed, subject to the | |
81 | values of the shell variables | |
82 | @env{HISTIGNORE} and @env{HISTCONTROL}. | |
83 | ||
84 | When the shell starts up, the history is initialized from the | |
85 | file named by the @env{HISTFILE} variable (default @file{~/.bash_history}). | |
86 | The file named by the value of @env{HISTFILE} is truncated, if | |
87 | necessary, to contain no more than the number of lines specified by | |
88 | the value of the @env{HISTFILESIZE} variable. | |
775e241e | 89 | When a shell with history enabled exits, the last |
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90 | @env{$HISTSIZE} lines are copied from the history list to the file |
91 | named by @env{$HISTFILE}. | |
92 | If the @code{histappend} shell option is set (@pxref{Bash Builtins}), | |
93 | the lines are appended to the history file, | |
94 | otherwise the history file is overwritten. | |
95 | If @env{HISTFILE} | |
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96 | is unset, or if the history file is unwritable, the history is not saved. |
97 | After saving the history, the history file is truncated | |
98 | to contain no more than @env{$HISTFILESIZE} lines. | |
99 | If @env{HISTFILESIZE} is unset, or set to null, a non-numeric value, or | |
100 | a numeric value less than zero, the history file is not truncated. | |
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101 | |
102 | If the @env{HISTTIMEFORMAT} is set, the time stamp information | |
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103 | associated with each history entry is written to the history file, |
104 | marked with the history comment character. | |
105 | When the history file is read, lines beginning with the history | |
106 | comment character followed immediately by a digit are interpreted | |
775e241e | 107 | as timestamps for the following history entry. |
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108 | |
109 | The builtin command @code{fc} may be used to list or edit and re-execute | |
110 | a portion of the history list. | |
111 | The @code{history} builtin may be used to display or modify the history | |
112 | list and manipulate the history file. | |
113 | When using command-line editing, search commands | |
114 | are available in each editing mode that provide access to the | |
115 | history list (@pxref{Commands For History}). | |
116 | ||
117 | The shell allows control over which commands are saved on the history | |
118 | list. The @env{HISTCONTROL} and @env{HISTIGNORE} | |
119 | variables may be set to cause the shell to save only a subset of the | |
120 | commands entered. | |
121 | The @code{cmdhist} | |
122 | shell option, if enabled, causes the shell to attempt to save each | |
123 | line of a multi-line command in the same history entry, adding | |
124 | semicolons where necessary to preserve syntactic correctness. | |
125 | The @code{lithist} | |
126 | shell option causes the shell to save the command with embedded newlines | |
127 | instead of semicolons. | |
128 | The @code{shopt} builtin is used to set these options. | |
cb41b9e7 | 129 | @xref{The Shopt Builtin}, for a description of @code{shopt}. |
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130 | |
131 | @node Bash History Builtins | |
132 | @section Bash History Builtins | |
133 | @cindex history builtins | |
134 | ||
135 | Bash provides two builtin commands which manipulate the | |
136 | history list and history file. | |
137 | ||
138 | @table @code | |
139 | ||
140 | @item fc | |
141 | @btindex fc | |
142 | @example | |
cc88a640 | 143 | @code{fc [-e @var{ename}] [-lnr] [@var{first}] [@var{last}]} |
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144 | @code{fc -s [@var{pat}=@var{rep}] [@var{command}]} |
145 | @end example | |
146 | ||
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147 | The first form selects a range of commands from @var{first} to |
148 | @var{last} from the history list and displays or edits and re-executes | |
149 | them. | |
150 | Both @var{first} and | |
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151 | @var{last} may be specified as a string (to locate the most recent |
152 | command beginning with that string) or as a number (an index into the | |
153 | history list, where a negative number is used as an offset from the | |
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154 | current command number). If @var{last} is not specified, it is set to |
155 | @var{first}. If @var{first} is not specified, it is set to the previous | |
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156 | command for editing and @minus{}16 for listing. If the @option{-l} flag is |
157 | given, the commands are listed on standard output. The @option{-n} flag | |
158 | suppresses the command numbers when listing. The @option{-r} flag | |
159 | reverses the order of the listing. Otherwise, the editor given by | |
160 | @var{ename} is invoked on a file containing those commands. If | |
161 | @var{ename} is not given, the value of the following variable expansion | |
162 | is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}. This says to use the | |
163 | value of the @env{FCEDIT} variable if set, or the value of the | |
164 | @env{EDITOR} variable if that is set, or @code{vi} if neither is set. | |
165 | When editing is complete, the edited commands are echoed and executed. | |
166 | ||
167 | In the second form, @var{command} is re-executed after each instance | |
168 | of @var{pat} in the selected command is replaced by @var{rep}. | |
775e241e | 169 | @var{command} is intepreted the same as @var{first} above. |
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170 | |
171 | A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so | |
172 | that typing @samp{r cc} runs the last command beginning with @code{cc} | |
173 | and typing @samp{r} re-executes the last command (@pxref{Aliases}). | |
174 | ||
175 | @item history | |
176 | @btindex history | |
177 | @example | |
178 | history [@var{n}] | |
179 | history -c | |
180 | history -d @var{offset} | |
cb41b9e7 | 181 | history -d @var{start}-@var{end} |
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182 | history [-anrw] [@var{filename}] |
183 | history -ps @var{arg} | |
184 | @end example | |
185 | ||
186 | With no options, display the history list with line numbers. | |
187 | Lines prefixed with a @samp{*} have been modified. | |
188 | An argument of @var{n} lists only the last @var{n} lines. | |
189 | If the shell variable @env{HISTTIMEFORMAT} is set and not null, | |
190 | it is used as a format string for @var{strftime} to display | |
191 | the time stamp associated with each displayed history entry. | |
192 | No intervening blank is printed between the formatted time stamp | |
193 | and the history line. | |
194 | ||
195 | Options, if supplied, have the following meanings: | |
196 | ||
197 | @table @code | |
198 | @item -c | |
199 | Clear the history list. This may be combined | |
200 | with the other options to replace the history list completely. | |
201 | ||
202 | @item -d @var{offset} | |
203 | Delete the history entry at position @var{offset}. | |
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204 | If @var{offset} is positive, it should be specified as it appears when |
205 | the history is displayed. | |
206 | If @var{offset} is negative, it is interpreted as relative to one greater | |
207 | than the last history position, so negative indices count back from the | |
208 | end of the history, and an index of @samp{-1} refers to the current | |
209 | @code{history -d} command. | |
210 | ||
211 | @item -d @var{start}-@var{end} | |
212 | Delete the history entries between positions @var{start} and @var{end}, | |
213 | inclusive. Positive and negative values for @var{start} and @var{end} | |
214 | are interpreted as described above. | |
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215 | |
216 | @item -a | |
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217 | Append the new history lines to the history file. |
218 | These are history lines entered since the beginning of the current | |
219 | Bash session, but not already appended to the history file. | |
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220 | |
221 | @item -n | |
222 | Append the history lines not already read from the history file | |
223 | to the current history list. These are lines appended to the history | |
224 | file since the beginning of the current Bash session. | |
225 | ||
226 | @item -r | |
775e241e | 227 | Read the history file and append its contents to |
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228 | the history list. |
229 | ||
230 | @item -w | |
775e241e | 231 | Write out the current history list to the history file. |
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232 | |
233 | @item -p | |
234 | Perform history substitution on the @var{arg}s and display the result | |
235 | on the standard output, without storing the results in the history list. | |
236 | ||
237 | @item -s | |
238 | The @var{arg}s are added to the end of | |
239 | the history list as a single entry. | |
240 | ||
241 | @end table | |
242 | ||
243 | When any of the @option{-w}, @option{-r}, @option{-a}, or @option{-n} options is | |
244 | used, if @var{filename} | |
245 | is given, then it is used as the history file. If not, then | |
246 | the value of the @env{HISTFILE} variable is used. | |
247 | ||
248 | @end table | |
249 | @end ifset | |
250 | ||
251 | @node History Interaction | |
252 | @section History Expansion | |
253 | @cindex history expansion | |
254 | ||
255 | The History library provides a history expansion feature that is similar | |
256 | to the history expansion provided by @code{csh}. This section | |
257 | describes the syntax used to manipulate the history information. | |
258 | ||
259 | History expansions introduce words from the history list into | |
260 | the input stream, making it easy to repeat commands, insert the | |
261 | arguments to a previous command into the current input line, or | |
262 | fix errors in previous commands quickly. | |
263 | ||
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264 | @ifset BashFeatures |
265 | History expansion is performed immediately after a complete line | |
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266 | is read, before the shell breaks it into words, and is performed |
267 | on each line individually. Bash attempts to inform the history | |
268 | expansion functions about quoting still in effect from previous lines. | |
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269 | @end ifset |
270 | ||
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271 | History expansion takes place in two parts. The first is to determine |
272 | which line from the history list should be used during substitution. | |
273 | The second is to select portions of that line for inclusion into the | |
274 | current one. The line selected from the history is called the | |
275 | @dfn{event}, and the portions of that line that are acted upon are | |
276 | called @dfn{words}. Various @dfn{modifiers} are available to manipulate | |
277 | the selected words. The line is broken into words in the same fashion | |
278 | that Bash does, so that several words | |
279 | surrounded by quotes are considered one word. | |
280 | History expansions are introduced by the appearance of the | |
281 | history expansion character, which is @samp{!} by default. | |
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282 | |
283 | History expansion implements shell-like quoting conventions: | |
284 | a backslash can be used to remove the special handling for the next character; | |
285 | single quotes enclose verbatim sequences of characters, and can be used to | |
286 | inhibit history expansion; | |
287 | and characters enclosed within double quotes may be subject to history | |
288 | expansion, since backslash can escape the history expansion character, | |
289 | but single quotes may not, since they are not treated specially within | |
290 | double quotes. | |
291 | ||
b585a9fa | 292 | @ifset BashFeatures |
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293 | When using the shell, only @samp{\} and @samp{'} may be used to escape the |
294 | history expansion character, but the history expansion character is | |
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295 | also treated as quoted if it immediately precedes the closing double quote |
296 | in a double-quoted string. | |
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297 | @end ifset |
298 | ||
299 | @ifset BashFeatures | |
300 | Several shell options settable with the @code{shopt} | |
cb41b9e7 | 301 | builtin (@pxref{The Shopt Builtin}) may be used to tailor |
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302 | the behavior of history expansion. If the |
303 | @code{histverify} shell option is enabled, and Readline | |
304 | is being used, history substitutions are not immediately passed to | |
305 | the shell parser. | |
306 | Instead, the expanded line is reloaded into the Readline | |
307 | editing buffer for further modification. | |
308 | If Readline is being used, and the @code{histreedit} | |
309 | shell option is enabled, a failed history expansion will be | |
310 | reloaded into the Readline editing buffer for correction. | |
311 | The @option{-p} option to the @code{history} builtin command | |
312 | may be used to see what a history expansion will do before using it. | |
313 | The @option{-s} option to the @code{history} builtin may be used to | |
314 | add commands to the end of the history list without actually executing | |
315 | them, so that they are available for subsequent recall. | |
316 | This is most useful in conjunction with Readline. | |
317 | ||
318 | The shell allows control of the various characters used by the | |
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319 | history expansion mechanism with the @code{histchars} variable, |
320 | as explained above (@pxref{Bash Variables}). The shell uses | |
321 | the history comment character to mark history timestamps when | |
322 | writing the history file. | |
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323 | @end ifset |
324 | ||
325 | @menu | |
326 | * Event Designators:: How to specify which history line to use. | |
327 | * Word Designators:: Specifying which words are of interest. | |
328 | * Modifiers:: Modifying the results of substitution. | |
329 | @end menu | |
330 | ||
331 | @node Event Designators | |
332 | @subsection Event Designators | |
333 | @cindex event designators | |
334 | ||
335 | An event designator is a reference to a command line entry in the | |
336 | history list. | |
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337 | Unless the reference is absolute, events are relative to the current |
338 | position in the history list. | |
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339 | @cindex history events |
340 | ||
341 | @table @asis | |
342 | ||
343 | @item @code{!} | |
344 | @ifset BashFeatures | |
345 | Start a history substitution, except when followed by a space, tab, | |
346 | the end of the line, @samp{=} or @samp{(} (when the | |
347 | @code{extglob} shell option is enabled using the @code{shopt} builtin). | |
348 | @end ifset | |
349 | @ifclear BashFeatures | |
350 | Start a history substitution, except when followed by a space, tab, | |
351 | the end of the line, or @samp{=}. | |
352 | @end ifclear | |
353 | ||
354 | @item @code{!@var{n}} | |
355 | Refer to command line @var{n}. | |
356 | ||
357 | @item @code{!-@var{n}} | |
358 | Refer to the command @var{n} lines back. | |
359 | ||
360 | @item @code{!!} | |
361 | Refer to the previous command. This is a synonym for @samp{!-1}. | |
362 | ||
363 | @item @code{!@var{string}} | |
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364 | Refer to the most recent command |
365 | preceding the current position in the history list | |
366 | starting with @var{string}. | |
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367 | |
368 | @item @code{!?@var{string}[?]} | |
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369 | Refer to the most recent command |
370 | preceding the current position in the history list | |
371 | containing @var{string}. | |
372 | The trailing | |
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373 | @samp{?} may be omitted if the @var{string} is followed immediately by |
374 | a newline. | |
375 | ||
376 | @item @code{^@var{string1}^@var{string2}^} | |
377 | Quick Substitution. Repeat the last command, replacing @var{string1} | |
378 | with @var{string2}. Equivalent to | |
379 | @code{!!:s/@var{string1}/@var{string2}/}. | |
380 | ||
381 | @item @code{!#} | |
382 | The entire command line typed so far. | |
383 | ||
384 | @end table | |
385 | ||
386 | @node Word Designators | |
387 | @subsection Word Designators | |
388 | ||
389 | Word designators are used to select desired words from the event. | |
390 | A @samp{:} separates the event specification from the word designator. It | |
391 | may be omitted if the word designator begins with a @samp{^}, @samp{$}, | |
392 | @samp{*}, @samp{-}, or @samp{%}. Words are numbered from the beginning | |
393 | of the line, with the first word being denoted by 0 (zero). Words are | |
394 | inserted into the current line separated by single spaces. | |
395 | ||
396 | @need 0.75 | |
397 | For example, | |
398 | ||
399 | @table @code | |
400 | @item !! | |
401 | designates the preceding command. When you type this, the preceding | |
402 | command is repeated in toto. | |
403 | ||
404 | @item !!:$ | |
405 | designates the last argument of the preceding command. This may be | |
406 | shortened to @code{!$}. | |
407 | ||
408 | @item !fi:2 | |
409 | designates the second argument of the most recent command starting with | |
410 | the letters @code{fi}. | |
411 | @end table | |
412 | ||
413 | @need 0.75 | |
414 | Here are the word designators: | |
415 | ||
416 | @table @code | |
417 | ||
418 | @item 0 (zero) | |
419 | The @code{0}th word. For many applications, this is the command word. | |
420 | ||
421 | @item @var{n} | |
422 | The @var{n}th word. | |
423 | ||
424 | @item ^ | |
425 | The first argument; that is, word 1. | |
426 | ||
427 | @item $ | |
428 | The last argument. | |
429 | ||
430 | @item % | |
431 | The word matched by the most recent @samp{?@var{string}?} search. | |
432 | ||
433 | @item @var{x}-@var{y} | |
434 | A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}. | |
435 | ||
436 | @item * | |
437 | All of the words, except the @code{0}th. This is a synonym for @samp{1-$}. | |
438 | It is not an error to use @samp{*} if there is just one word in the event; | |
439 | the empty string is returned in that case. | |
440 | ||
441 | @item @var{x}* | |
442 | Abbreviates @samp{@var{x}-$} | |
443 | ||
444 | @item @var{x}- | |
445 | Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word. | |
446 | ||
447 | @end table | |
448 | ||
449 | If a word designator is supplied without an event specification, the | |
450 | previous command is used as the event. | |
451 | ||
452 | @node Modifiers | |
453 | @subsection Modifiers | |
454 | ||
455 | After the optional word designator, you can add a sequence of one or more | |
456 | of the following modifiers, each preceded by a @samp{:}. | |
457 | ||
458 | @table @code | |
459 | ||
460 | @item h | |
461 | Remove a trailing pathname component, leaving only the head. | |
462 | ||
463 | @item t | |
cc88a640 | 464 | Remove all leading pathname components, leaving the tail. |
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465 | |
466 | @item r | |
467 | Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving | |
468 | the basename. | |
469 | ||
470 | @item e | |
471 | Remove all but the trailing suffix. | |
472 | ||
473 | @item p | |
474 | Print the new command but do not execute it. | |
475 | ||
476 | @ifset BashFeatures | |
477 | @item q | |
478 | Quote the substituted words, escaping further substitutions. | |
479 | ||
480 | @item x | |
481 | Quote the substituted words as with @samp{q}, | |
482 | but break into words at spaces, tabs, and newlines. | |
483 | @end ifset | |
484 | ||
485 | @item s/@var{old}/@var{new}/ | |
486 | Substitute @var{new} for the first occurrence of @var{old} in the | |
487 | event line. Any delimiter may be used in place of @samp{/}. | |
488 | The delimiter may be quoted in @var{old} and @var{new} | |
489 | with a single backslash. If @samp{&} appears in @var{new}, | |
490 | it is replaced by @var{old}. A single backslash will quote | |
491 | the @samp{&}. The final delimiter is optional if it is the last | |
492 | character on the input line. | |
493 | ||
494 | @item & | |
495 | Repeat the previous substitution. | |
496 | ||
497 | @item g | |
498 | @itemx a | |
499 | Cause changes to be applied over the entire event line. Used in | |
500 | conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/}, | |
501 | or with @samp{&}. | |
502 | ||
503 | @item G | |
504 | Apply the following @samp{s} modifier once to each word in the event. | |
505 | ||
506 | @end table |