lib/readline/doc/hsuser.texinfo

   1 @ignore
   2 This file documents the user interface to the GNU History library.
   3
   4 Copyright (C) 1988, 1991, 1996 Free Software Foundation, Inc.
   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
  29 @ifset BashFeatures
  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.
  34 @end ifset
  35 @ifclear BashFeatures
  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.  For
  38 information on using the GNU History Library in your own programs,
  39 @pxref{Programming with GNU History}.
  40 @end ifclear
  41
  42 @ifset BashFeatures
  43 @menu
  44 * Bash History Facilities::     How Bash lets you manipulate your command
  45                                 history.
  46 * Bash History Builtins::       The Bash builtin commands that manipulate
  47                                 the command history.
  48 * History Interaction::         What it feels like using History as a user.
  49 @end menu
  50 @end ifset
  51 @ifclear BashFeatures
  52 @menu
  53 * History Interaction::         What it feels like using History as a user.
  54 @end menu
  55 @end ifclear
  56
  57 @ifset BashFeatures
  58 @node Bash History Facilities
  59 @section Bash History Facilities
  60 @cindex command history
  61 @cindex history list
  62
  63 When the @samp{-o history} option to the @code{set} builtin
  64 is enabled (@pxref{The Set Builtin}),
  65 the shell provides access to the @var{command history},
  66 the list of commands previously typed.  The text of the last
  67 @code{HISTSIZE}
  68 commands (default 500) is saved in a history list.  The shell
  69 stores each command in the history list prior to parameter and
  70 variable expansion
  71 but after history expansion is performed, subject to the
  72 values of the shell variables
  73 @code{HISTIGNORE} and @code{HISTCONTROL}.
  74 When the shell starts up, the history is initialized from the
  75 file named by the @code{HISTFILE} variable (default @file{~/.bash_history}).
  76 @code{HISTFILE} is truncated, if necessary, to contain no more than
  77 the number of lines specified by the value of the @code{HISTFILESIZE}
  78 variable.  When an interactive shell exits, the last
  79 @code{HISTSIZE} lines are copied from the history list to @code{HISTFILE}.
  80 If the @code{histappend} shell option is set (@pxref{Bash Builtins}),
  81 the lines are appended to the history file,
  82 otherwise the history file is overwritten.
  83 If @code{HISTFILE}
  84 is unset, or if the history file is unwritable, the history is
  85 not saved.  After saving the history, the history file is truncated
  86 to contain no more than @code{$HISTFILESIZE}
  87 lines.  If @code{HISTFILESIZE} is not set, no truncation is performed.
  88
  89 The builtin command @code{fc} may be used to list or edit and re-execute
  90 a portion of the history list.
  91 The @code{history} builtin can be used to display or modify the history
  92 list and manipulate the history file.
  93 When using the command-line editing, search commands
  94 are available in each editing mode that provide access to the
  95 history list.
  96
  97 The shell allows control over which commands are saved on the history
  98 list.  The @code{HISTCONTROL} and @code{HISTIGNORE}
  99 variables may be set to cause the shell to save only a subset of the
 100 commands entered.
 101 The @code{cmdhist}
 102 shell option, if enabled, causes the shell to attempt to save each
 103 line of a multi-line command in the same history entry, adding
 104 semicolons where necessary to preserve syntactic correctness.
 105 The @code{lithist}
 106 shell option causes the shell to save the command with embedded newlines
 107 instead of semicolons.
 108 @xref{Bash Builtins}, for a description of @code{shopt}.
 109
 110 @node Bash History Builtins
 111 @section Bash History Builtins
 112 @cindex history builtins
 113
 114 Bash provides two builtin commands that allow you to manipulate the
 115 history list and history file.
 116
 117 @table @code
 118
 119 @item fc
 120 @btindex fc
 121 @example
 122 @code{fc [-e @var{ename}] [-nlr] [@var{first}] [@var{last}]}
 123 @code{fc -s [@var{pat}=@var{rep}] [@var{command}]}
 124 @end example
 125
 126 Fix Command.  In the first form, a range of commands from @var{first} to
 127 @var{last} is selected from the history list.  Both @var{first} and
 128 @var{last} may be specified as a string (to locate the most recent
 129 command beginning with that string) or as a number (an index into the
 130 history list, where a negative number is used as an offset from the
 131 current command number).  If @var{last} is not specified it is set to
 132 @var{first}.  If @var{first} is not specified it is set to the previous
 133 command for editing and @minus{}16 for listing.  If the @samp{-l} flag is
 134 given, the commands are listed on standard output.  The @samp{-n} flag
 135 suppresses the command numbers when listing.  The @samp{-r} flag
 136 reverses the order of the listing.  Otherwise, the editor given by
 137 @var{ename} is invoked on a file containing those commands.  If
 138 @var{ename} is not given, the value of the following variable expansion
 139 is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}.  This says to use the
 140 value of the @code{FCEDIT} variable if set, or the value of the
 141 @code{EDITOR} variable if that is set, or @code{vi} if neither is set.
 142 When editing is complete, the edited commands are echoed and executed.
 143
 144 In the second form, @var{command} is re-executed after each instance
 145 of @var{pat} in the selected command is replaced by @var{rep}.
 146
 147 A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so
 148 that typing @samp{r cc} runs the last command beginning with @code{cc}
 149 and typing @samp{r} re-executes the last command (@pxref{Aliases}).
 150
 151 @item history
 152 @btindex history
 153 @example
 154 history [-c] [@var{n}]
 155 history [-anrw] [@var{filename}]
 156 history -ps @var{arg}
 157 @end example
 158
 159 Display the history list with line numbers.  Lines prefixed with
 160 with a @samp{*} have been modified.  An argument of @var{n} says
 161 to list only the last @var{n} lines.  Options, if supplied, have
 162 the following meanings:
 163
 164 @table @code
 165 @item -w
 166 Write out the current history to the history file.
 167
 168 @item -r
 169 Read the current history file and append its contents to
 170 the history list.
 171
 172 @item -a
 173 Append the new
 174 history lines (history lines entered since the beginning of the
 175 current Bash session) to the history file.
 176
 177 @item -n
 178 Append the history lines not already read from the history file
 179 to the current history list.  These are lines appended to the history
 180 file since the beginning of the current Bash session.
 181
 182 @item -c
 183 Clear the history list.  This may be combined
 184 with the other options to replace the history list completely.
 185
 186 @item -s
 187 The @var{arg}s are added to the end of
 188 the history list as a single entry.
 189
 190 @item -p
 191 Perform history substitution on the @var{arg}s and display the result
 192 on the standard output, without storing the results in the history list.
 193 @end table
 194
 195 When the @samp{-w}, @samp{-r}, @samp{-a}, or @samp{-n} option is
 196 used, if @var{filename}
 197 is given, then it is used as the history file.  If not, then
 198 the value of the @code{HISTFILE} variable is used.
 199
 200 @end table
 201 @end ifset
 202
 203 @node History Interaction
 204 @section History Expansion
 205 @cindex history expansion
 206
 207 The History library provides a history expansion feature that is similar
 208 to the history expansion provided by @code{csh}.  This section
 209 describes the syntax used to manipulate the history information.
 210
 211 History expansions introduce words from the history list into
 212 the input stream, making it easy to repeat commands, insert the
 213 arguments to a previous command into the current input line, or
 214 fix errors in previous commands quickly.
 215
 216 History expansion takes place in two parts.  The first is to determine
 217 which line from the history list should be used during substitution.
 218 The second is to select portions of that line for inclusion into the
 219 current one.  The line selected from the history is called the
 220 @dfn{event}, and the portions of that line that are acted upon are
 221 called @dfn{words}.  Various @dfn{modifiers} are available to manipulate
 222 the selected words.  The line is broken into words in the same fashion
 223 that Bash does, so that several words
 224 surrounded by quotes are considered one word.
 225 History expansions are introduced by the appearance of the
 226 history expansion character, which is @samp{!} by default.
 227 @ifset BashFeatures
 228 Only @samp{\} and @samp{'} may be used to escape the history expansion
 229 character.
 230 @end ifset
 231
 232 @ifset BashFeatures
 233 Several shell options settable with the @code{shopt}
 234 builtin (@pxref{Bash Builtins}) may be used to tailor
 235 the behavior of history expansion.  If the
 236 @code{histverify} shell option is enabled, and Readline
 237 is being used, history substitutions are not immediately passed to
 238 the shell parser.
 239 Instead, the expanded line is reloaded into the Readline
 240 editing buffer for further modification.
 241 If Readline is being used, and the @code{histreedit}
 242 shell option is enabled, a failed history expansion will be
 243 reloaded into the Readline editing buffer for correction.
 244 The @samp{-p} option to the @code{history} builtin command
 245 may be used to see what a history expansion will do before using it.
 246 The @samp{-s} option to the @code{history} builtin may be used to
 247 add commands to the end of the history list without actually executing
 248 them, so that they are available for subsequent recall.
 249 This is most useful in conjunction with Readline.
 250
 251 The shell allows control of the various characters used by the
 252 history expansion mechanism with the @code{histchars} variable.
 253 @end ifset
 254
 255 @menu
 256 * Event Designators::   How to specify which history line to use.
 257 * Word Designators::    Specifying which words are of interest.
 258 * Modifiers::           Modifying the results of substitution.
 259 @end menu
 260
 261 @node Event Designators
 262 @subsection Event Designators
 263 @cindex event designators
 264
 265 An event designator is a reference to a command line entry in the
 266 history list.
 267 @cindex history events
 268
 269 @table @asis
 270
 271 @item @code{!}
 272 Start a history substitution, except when followed by a space, tab,
 273 the end of the line, @samp{=} or @samp{(}.
 274
 275 @item @code{!@var{n}}
 276 Refer to command line @var{n}.
 277
 278 @item @code{!-@var{n}}
 279 Refer to the command @var{n} lines back.
 280
 281 @item @code{!!}
 282 Refer to the previous command.  This is a synonym for @samp{!-1}.
 283
 284 @item @code{!@var{string}}
 285 Refer to the most recent command starting with @var{string}.
 286
 287 @item @code{!?@var{string}[?]}
 288 Refer to the most recent command containing @var{string}.  The trailing
 289 @samp{?} may be omitted if the @var{string} is followed immediately by
 290 a newline.
 291
 292 @item @code{^@var{string1}^@var{string2}^}
 293 Quick Substitution.  Repeat the last command, replacing @var{string1}
 294 with @var{string2}.  Equivalent to
 295 @code{!!:s/@var{string1}/@var{string2}/}.
 296
 297 @item @code{!#}
 298 The entire command line typed so far.
 299
 300 @end table
 301
 302 @node Word Designators
 303 @subsection Word Designators
 304
 305 Word designators are used to select desired words from the event.
 306 A @samp{:} separates the event specification from the word designator.  It
 307 may be omitted if the word designator begins with a @samp{^}, @samp{$},
 308 @samp{*}, @samp{-}, or @samp{%}.  Words are numbered from the beginning
 309 of the line, with the first word being denoted by 0 (zero).  Words are
 310 inserted into the current line separated by single spaces.
 311
 312 @table @code
 313
 314 @item 0 (zero)
 315 The @code{0}th word.  For many applications, this is the command word.
 316
 317 @item @var{n}
 318 The @var{n}th word.
 319
 320 @item ^
 321 The first argument; that is, word 1.
 322
 323 @item $
 324 The last argument.
 325
 326 @item %
 327 The word matched by the most recent @samp{?@var{string}?} search.
 328
 329 @item @var{x}-@var{y}
 330 A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
 331
 332 @item *
 333 All of the words, except the @code{0}th.  This is a synonym for @samp{1-$}.
 334 It is not an error to use @samp{*} if there is just one word in the event;
 335 the empty string is returned in that case.
 336
 337 @item @var{x}*
 338 Abbreviates @samp{@var{x}-$}
 339
 340 @item @var{x}-
 341 Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
 342
 343 @end table
 344
 345 If a word designator is supplied without an event specification, the
 346 previous command is used as the event.
 347
 348 @node Modifiers
 349 @subsection Modifiers
 350
 351 After the optional word designator, you can add a sequence of one or more
 352 of the following modifiers, each preceded by a @samp{:}.
 353
 354 @table @code
 355
 356 @item h
 357 Remove a trailing pathname component, leaving only the head.
 358
 359 @item t
 360 Remove all leading  pathname  components, leaving the tail.
 361
 362 @item r
 363 Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
 364 the basename.
 365
 366 @item e
 367 Remove all but the trailing suffix.
 368
 369 @item p
 370 Print the new command but do not execute it.
 371
 372 @ifset BashFeatures
 373 @item q
 374 Quote the substituted words, escaping further substitutions.
 375
 376 @item x
 377 Quote the substituted words as with @samp{q},
 378 but break into words at spaces, tabs, and newlines.
 379 @end ifset
 380
 381 @item s/@var{old}/@var{new}/
 382 Substitute @var{new} for the first occurrence of @var{old} in the
 383 event line.  Any delimiter may be used in place of @samp{/}.
 384 The delimiter may be quoted in @var{old} and @var{new}
 385 with a single backslash.  If @samp{&} appears in @var{new},
 386 it is replaced by @var{old}.  A single backslash will quote
 387 the @samp{&}.  The final delimiter is optional if it is the last
 388 character on the input line.
 389
 390 @item &
 391 Repeat the previous substitution.
 392
 393 @item g
 394 Cause changes to be applied over the entire event line.  Used in
 395 conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/},
 396 or with @samp{&}.
 397
 398 @end table