2 This file documents the user interface to the GNU History library.
4 Copyright (C) 1988, 1991, 1996 Free Software Foundation, Inc.
5 Authored by Brian Fox and Chet Ramey.
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8 provided the copyright notice and this permission notice are preserved on
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26 @node Using History Interactively
27 @chapter Using History Interactively
30 This chapter describes how to use the GNU History Library interactively,
31 from a user's standpoint. It should be considered a user's guide. For
32 information on using the GNU History Library in other programs,
33 see the GNU Readline Library Manual.
36 This chapter describes how to use the GNU History Library interactively,
37 from a user's standpoint. It should be considered a user's guide.
39 @c information on using the GNU History Library in your own programs,
40 @c @pxref{Programming with GNU History}.
45 * Bash History Facilities:: How Bash lets you manipulate your command
47 * Bash History Builtins:: The Bash builtin commands that manipulate
49 * History Interaction:: What it feels like using History as a user.
54 * History Interaction:: What it feels like using History as a user.
59 @node Bash History Facilities
60 @section Bash History Facilities
61 @cindex command history
64 When the @samp{-o history} option to the @code{set} builtin
65 is enabled (@pxref{The Set Builtin}),
66 the shell provides access to the @var{command history},
67 the list of commands previously typed. The text of the last
69 commands (default 500) is saved in a history list. The shell
70 stores each command in the history list prior to parameter and
72 but after history expansion is performed, subject to the
73 values of the shell variables
74 @code{HISTIGNORE} and @code{HISTCONTROL}.
75 When the shell starts up, the history is initialized from the
76 file named by the @code{HISTFILE} variable (default @file{~/.bash_history}).
77 @code{HISTFILE} is truncated, if necessary, to contain no more than
78 the number of lines specified by the value of the @code{HISTFILESIZE}
79 variable. When an interactive shell exits, the last
80 @code{HISTSIZE} lines are copied from the history list to @code{HISTFILE}.
81 If the @code{histappend} shell option is set (@pxref{Bash Builtins}),
82 the lines are appended to the history file,
83 otherwise the history file is overwritten.
85 is unset, or if the history file is unwritable, the history is
86 not saved. After saving the history, the history file is truncated
87 to contain no more than @code{$HISTFILESIZE}
88 lines. If @code{HISTFILESIZE} is not set, no truncation is performed.
90 The builtin command @code{fc} may be used to list or edit and re-execute
91 a portion of the history list.
92 The @code{history} builtin can be used to display or modify the history
93 list and manipulate the history file.
94 When using the command-line editing, search commands
95 are available in each editing mode that provide access to the
98 The shell allows control over which commands are saved on the history
99 list. The @code{HISTCONTROL} and @code{HISTIGNORE}
100 variables may be set to cause the shell to save only a subset of the
103 shell option, if enabled, causes the shell to attempt to save each
104 line of a multi-line command in the same history entry, adding
105 semicolons where necessary to preserve syntactic correctness.
107 shell option causes the shell to save the command with embedded newlines
108 instead of semicolons.
109 @xref{Bash Builtins}, for a description of @code{shopt}.
111 @node Bash History Builtins
112 @section Bash History Builtins
113 @cindex history builtins
115 Bash provides two builtin commands that allow you to manipulate the
116 history list and history file.
123 @code{fc [-e @var{ename}] [-nlr] [@var{first}] [@var{last}]}
124 @code{fc -s [@var{pat}=@var{rep}] [@var{command}]}
127 Fix Command. In the first form, a range of commands from @var{first} to
128 @var{last} is selected from the history list. Both @var{first} and
129 @var{last} may be specified as a string (to locate the most recent
130 command beginning with that string) or as a number (an index into the
131 history list, where a negative number is used as an offset from the
132 current command number). If @var{last} is not specified it is set to
133 @var{first}. If @var{first} is not specified it is set to the previous
134 command for editing and @minus{}16 for listing. If the @samp{-l} flag is
135 given, the commands are listed on standard output. The @samp{-n} flag
136 suppresses the command numbers when listing. The @samp{-r} flag
137 reverses the order of the listing. Otherwise, the editor given by
138 @var{ename} is invoked on a file containing those commands. If
139 @var{ename} is not given, the value of the following variable expansion
140 is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}. This says to use the
141 value of the @code{FCEDIT} variable if set, or the value of the
142 @code{EDITOR} variable if that is set, or @code{vi} if neither is set.
143 When editing is complete, the edited commands are echoed and executed.
145 In the second form, @var{command} is re-executed after each instance
146 of @var{pat} in the selected command is replaced by @var{rep}.
148 A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so
149 that typing @samp{r cc} runs the last command beginning with @code{cc}
150 and typing @samp{r} re-executes the last command (@pxref{Aliases}).
155 history [-c] [@var{n}]
156 history [-anrw] [@var{filename}]
157 history -ps @var{arg}
160 Display the history list with line numbers. Lines prefixed with
161 with a @samp{*} have been modified. An argument of @var{n} says
162 to list only the last @var{n} lines. Options, if supplied, have
163 the following meanings:
167 Write out the current history to the history file.
170 Read the current history file and append its contents to
175 history lines (history lines entered since the beginning of the
176 current Bash session) to the history file.
179 Append the history lines not already read from the history file
180 to the current history list. These are lines appended to the history
181 file since the beginning of the current Bash session.
184 Clear the history list. This may be combined
185 with the other options to replace the history list completely.
188 The @var{arg}s are added to the end of
189 the history list as a single entry.
192 Perform history substitution on the @var{arg}s and display the result
193 on the standard output, without storing the results in the history list.
196 When the @samp{-w}, @samp{-r}, @samp{-a}, or @samp{-n} option is
197 used, if @var{filename}
198 is given, then it is used as the history file. If not, then
199 the value of the @code{HISTFILE} variable is used.
204 @node History Interaction
205 @section History Expansion
206 @cindex history expansion
208 The History library provides a history expansion feature that is similar
209 to the history expansion provided by @code{csh}. This section
210 describes the syntax used to manipulate the history information.
212 History expansions introduce words from the history list into
213 the input stream, making it easy to repeat commands, insert the
214 arguments to a previous command into the current input line, or
215 fix errors in previous commands quickly.
217 History expansion takes place in two parts. The first is to determine
218 which line from the history list should be used during substitution.
219 The second is to select portions of that line for inclusion into the
220 current one. The line selected from the history is called the
221 @dfn{event}, and the portions of that line that are acted upon are
222 called @dfn{words}. Various @dfn{modifiers} are available to manipulate
223 the selected words. The line is broken into words in the same fashion
224 that Bash does, so that several words
225 surrounded by quotes are considered one word.
226 History expansions are introduced by the appearance of the
227 history expansion character, which is @samp{!} by default.
229 Only @samp{\} and @samp{'} may be used to escape the history expansion
234 Several shell options settable with the @code{shopt}
235 builtin (@pxref{Bash Builtins}) may be used to tailor
236 the behavior of history expansion. If the
237 @code{histverify} shell option is enabled, and Readline
238 is being used, history substitutions are not immediately passed to
240 Instead, the expanded line is reloaded into the Readline
241 editing buffer for further modification.
242 If Readline is being used, and the @code{histreedit}
243 shell option is enabled, a failed history expansion will be
244 reloaded into the Readline editing buffer for correction.
245 The @samp{-p} option to the @code{history} builtin command
246 may be used to see what a history expansion will do before using it.
247 The @samp{-s} option to the @code{history} builtin may be used to
248 add commands to the end of the history list without actually executing
249 them, so that they are available for subsequent recall.
250 This is most useful in conjunction with Readline.
252 The shell allows control of the various characters used by the
253 history expansion mechanism with the @code{histchars} variable.
257 * Event Designators:: How to specify which history line to use.
258 * Word Designators:: Specifying which words are of interest.
259 * Modifiers:: Modifying the results of substitution.
262 @node Event Designators
263 @subsection Event Designators
264 @cindex event designators
266 An event designator is a reference to a command line entry in the
268 @cindex history events
273 Start a history substitution, except when followed by a space, tab,
274 the end of the line, @samp{=} or @samp{(}.
276 @item @code{!@var{n}}
277 Refer to command line @var{n}.
279 @item @code{!-@var{n}}
280 Refer to the command @var{n} lines back.
283 Refer to the previous command. This is a synonym for @samp{!-1}.
285 @item @code{!@var{string}}
286 Refer to the most recent command starting with @var{string}.
288 @item @code{!?@var{string}[?]}
289 Refer to the most recent command containing @var{string}. The trailing
290 @samp{?} may be omitted if the @var{string} is followed immediately by
293 @item @code{^@var{string1}^@var{string2}^}
294 Quick Substitution. Repeat the last command, replacing @var{string1}
295 with @var{string2}. Equivalent to
296 @code{!!:s/@var{string1}/@var{string2}/}.
299 The entire command line typed so far.
303 @node Word Designators
304 @subsection Word Designators
306 Word designators are used to select desired words from the event.
307 A @samp{:} separates the event specification from the word designator. It
308 may be omitted if the word designator begins with a @samp{^}, @samp{$},
309 @samp{*}, @samp{-}, or @samp{%}. Words are numbered from the beginning
310 of the line, with the first word being denoted by 0 (zero). Words are
311 inserted into the current line separated by single spaces.
316 The @code{0}th word. For many applications, this is the command word.
322 The first argument; that is, word 1.
328 The word matched by the most recent @samp{?@var{string}?} search.
330 @item @var{x}-@var{y}
331 A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
334 All of the words, except the @code{0}th. This is a synonym for @samp{1-$}.
335 It is not an error to use @samp{*} if there is just one word in the event;
336 the empty string is returned in that case.
339 Abbreviates @samp{@var{x}-$}
342 Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
346 If a word designator is supplied without an event specification, the
347 previous command is used as the event.
350 @subsection Modifiers
352 After the optional word designator, you can add a sequence of one or more
353 of the following modifiers, each preceded by a @samp{:}.
358 Remove a trailing pathname component, leaving only the head.
361 Remove all leading pathname components, leaving the tail.
364 Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
368 Remove all but the trailing suffix.
371 Print the new command but do not execute it.
375 Quote the substituted words, escaping further substitutions.
378 Quote the substituted words as with @samp{q},
379 but break into words at spaces, tabs, and newlines.
382 @item s/@var{old}/@var{new}/
383 Substitute @var{new} for the first occurrence of @var{old} in the
384 event line. Any delimiter may be used in place of @samp{/}.
385 The delimiter may be quoted in @var{old} and @var{new}
386 with a single backslash. If @samp{&} appears in @var{new},
387 it is replaced by @var{old}. A single backslash will quote
388 the @samp{&}. The final delimiter is optional if it is the last
389 character on the input line.
392 Repeat the previous substitution.
395 Cause changes to be applied over the entire event line. Used in
396 conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/},