readline/doc/inc-hist.texinfo

   1 @ignore
   2 This file documents the user interface to the GNU History library.
   3
   4 Copyright (C) 1988-1999 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 @c @ifclear BashFeatures
  30 @c @defcodeindex bt
  31 @c @end ifclear
  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 GNU History Library interactively,
  42 from a user's standpoint.  It should be considered a user's guide.
  43 @c  For
  44 @c information on using the GNU History Library in your own programs,
  45 @c @pxref{Programming with GNU History}.
  46 @end ifclear
  47
  48 @ifset BashFeatures
  49 @menu
  50 * Bash History Facilities::     How Bash lets you manipulate your command
  51                                 history.
  52 * Bash History Builtins::       The Bash builtin commands that manipulate
  53                                 the command history.
  54 * History Interaction::         What it feels like using History as a user.
  55 @end menu
  56 @end ifset
  57 @ifclear BashFeatures
  58 @menu
  59 * History Interaction::         What it feels like using History as a user.
  60 @end menu
  61 @end ifclear
  62
  63 @ifset BashFeatures
  64 @node Bash History Facilities
  65 @section Bash History Facilities
  66 @cindex command history
  67 @cindex history list
  68
  69 When the @samp{-o history} option to the @code{set} builtin
  70 is enabled (@pxref{The Set Builtin}),
  71 the shell provides access to the @var{command history},
  72 the list of commands previously typed.
  73 The value of the @code{HISTSIZE} shell variable is used as the
  74 number of commands to save in a history list.
  75 The text of the last @code{$HISTSIZE}
  76 commands (default 500) is saved.
  77 The shell stores each command in the history list prior to
  78 parameter and variable expansion
  79 but after history expansion is performed, subject to the
  80 values of the shell variables
  81 @code{HISTIGNORE} and @code{HISTCONTROL}.
  82
  83 When the shell starts up, the history is initialized from the
  84 file named by the @code{HISTFILE} variable (default @file{~/.bash_history}).
  85 The file named by the value of @code{HISTFILE} is truncated, if
  86 necessary, to contain no more than the number of lines specified by
  87 the value of the @code{HISTFILESIZE} variable.
  88 When an interactive shell exits, the last
  89 @code{$HISTSIZE} lines are copied from the history list to the file
  90 named by @code{$HISTFILE}.
  91 If the @code{histappend} shell option is set (@pxref{Bash Builtins}),
  92 the lines are appended to the history file,
  93 otherwise the history file is overwritten.
  94 If @code{HISTFILE}
  95 is unset, or if the history file is unwritable, the history is
  96 not saved.  After saving the history, the history file is truncated
  97 to contain no more than @code{$HISTFILESIZE}
  98 lines.  If @code{HISTFILESIZE} is not set, no truncation is performed.
  99
 100 The builtin command @code{fc} may be used to list or edit and re-execute
 101 a portion of the history list.
 102 The @code{history} builtin may be used to display or modify the history
 103 list and manipulate the history file.
 104 When using command-line editing, search commands
 105 are available in each editing mode that provide access to the
 106 history list (@pxref{Commands For History}).
 107
 108 The shell allows control over which commands are saved on the history
 109 list.  The @code{HISTCONTROL} and @code{HISTIGNORE}
 110 variables may be set to cause the shell to save only a subset of the
 111 commands entered.
 112 The @code{cmdhist}
 113 shell option, if enabled, causes the shell to attempt to save each
 114 line of a multi-line command in the same history entry, adding
 115 semicolons where necessary to preserve syntactic correctness.
 116 The @code{lithist}
 117 shell option causes the shell to save the command with embedded newlines
 118 instead of semicolons.
 119 The @code{shopt} builtin is used to set these options.
 120 @xref{Bash Builtins}, for a description of @code{shopt}.
 121
 122 @node Bash History Builtins
 123 @section Bash History Builtins
 124 @cindex history builtins
 125
 126 Bash provides two builtin commands which manipulate the
 127 history list and history file.
 128
 129 @table @code
 130
 131 @item fc
 132 @btindex fc
 133 @example
 134 @code{fc [-e @var{ename}] [-nlr] [@var{first}] [@var{last}]}
 135 @code{fc -s [@var{pat}=@var{rep}] [@var{command}]}
 136 @end example
 137
 138 Fix Command.  In the first form, a range of commands from @var{first} to
 139 @var{last} is selected from the history list.  Both @var{first} and
 140 @var{last} may be specified as a string (to locate the most recent
 141 command beginning with that string) or as a number (an index into the
 142 history list, where a negative number is used as an offset from the
 143 current command number).  If @var{last} is not specified it is set to
 144 @var{first}.  If @var{first} is not specified it is set to the previous
 145 command for editing and @minus{}16 for listing.  If the @samp{-l} flag is
 146 given, the commands are listed on standard output.  The @samp{-n} flag
 147 suppresses the command numbers when listing.  The @samp{-r} flag
 148 reverses the order of the listing.  Otherwise, the editor given by
 149 @var{ename} is invoked on a file containing those commands.  If
 150 @var{ename} is not given, the value of the following variable expansion
 151 is used: @code{$@{FCEDIT:-$@{EDITOR:-vi@}@}}.  This says to use the
 152 value of the @code{FCEDIT} variable if set, or the value of the
 153 @code{EDITOR} variable if that is set, or @code{vi} if neither is set.
 154 When editing is complete, the edited commands are echoed and executed.
 155
 156 In the second form, @var{command} is re-executed after each instance
 157 of @var{pat} in the selected command is replaced by @var{rep}.
 158
 159 A useful alias to use with the @code{fc} command is @code{r='fc -s'}, so
 160 that typing @samp{r cc} runs the last command beginning with @code{cc}
 161 and typing @samp{r} re-executes the last command (@pxref{Aliases}).
 162
 163 @item history
 164 @btindex history
 165 @example
 166 history [@var{n}]
 167 history -c
 168 history -d @var{offset}
 169 history [-anrw] [@var{filename}]
 170 history -ps @var{arg}
 171 @end example
 172
 173 With no options, display the history list with line numbers.
 174 Lines prefixed with with a @samp{*} have been modified.
 175 An argument of @var{n} lists only the last @var{n} lines.
 176 Options, if supplied, have the following meanings:
 177
 178 @table @code
 179 @item -c
 180 Clear the history list.  This may be combined
 181 with the other options to replace the history list completely.
 182
 183 @item -d @var{offset}
 184 Delete the history entry at position @var{offset}.
 185 @var{offset} should be specified as it appears when the history is
 186 displayed.
 187
 188 @item -a
 189 Append the new
 190 history lines (history lines entered since the beginning of the
 191 current Bash session) to the history file.
 192
 193 @item -n
 194 Append the history lines not already read from the history file
 195 to the current history list.  These are lines appended to the history
 196 file since the beginning of the current Bash session.
 197
 198 @item -r
 199 Read the current history file and append its contents to
 200 the history list.
 201
 202 @item -w
 203 Write out the current history to the history file.
 204
 205 @item -p
 206 Perform history substitution on the @var{arg}s and display the result
 207 on the standard output, without storing the results in the history list.
 208
 209 @item -s
 210 The @var{arg}s are added to the end of
 211 the history list as a single entry.
 212
 213 @end table
 214
 215 When any of the @samp{-w}, @samp{-r}, @samp{-a}, or @samp{-n} options is
 216 used, if @var{filename}
 217 is given, then it is used as the history file.  If not, then
 218 the value of the @code{HISTFILE} variable is used.
 219
 220 @end table
 221 @end ifset
 222
 223 @node History Interaction
 224 @section History Expansion
 225 @cindex history expansion
 226
 227 The History library provides a history expansion feature that is similar
 228 to the history expansion provided by @code{csh}.  This section
 229 describes the syntax used to manipulate the history information.
 230
 231 History expansions introduce words from the history list into
 232 the input stream, making it easy to repeat commands, insert the
 233 arguments to a previous command into the current input line, or
 234 fix errors in previous commands quickly.
 235
 236 History expansion takes place in two parts.  The first is to determine
 237 which line from the history list should be used during substitution.
 238 The second is to select portions of that line for inclusion into the
 239 current one.  The line selected from the history is called the
 240 @dfn{event}, and the portions of that line that are acted upon are
 241 called @dfn{words}.  Various @dfn{modifiers} are available to manipulate
 242 the selected words.  The line is broken into words in the same fashion
 243 that Bash does, so that several words
 244 surrounded by quotes are considered one word.
 245 History expansions are introduced by the appearance of the
 246 history expansion character, which is @samp{!} by default.
 247 @ifset BashFeatures
 248 Only @samp{\} and @samp{'} may be used to escape the history expansion
 249 character.
 250 @end ifset
 251
 252 @ifset BashFeatures
 253 Several shell options settable with the @code{shopt}
 254 builtin (@pxref{Bash Builtins}) may be used to tailor
 255 the behavior of history expansion.  If the
 256 @code{histverify} shell option is enabled, and Readline
 257 is being used, history substitutions are not immediately passed to
 258 the shell parser.
 259 Instead, the expanded line is reloaded into the Readline
 260 editing buffer for further modification.
 261 If Readline is being used, and the @code{histreedit}
 262 shell option is enabled, a failed history expansion will be
 263 reloaded into the Readline editing buffer for correction.
 264 The @samp{-p} option to the @code{history} builtin command
 265 may be used to see what a history expansion will do before using it.
 266 The @samp{-s} option to the @code{history} builtin may be used to
 267 add commands to the end of the history list without actually executing
 268 them, so that they are available for subsequent recall.
 269 This is most useful in conjunction with Readline.
 270
 271 The shell allows control of the various characters used by the
 272 history expansion mechanism with the @code{histchars} variable.
 273 @end ifset
 274
 275 @menu
 276 * Event Designators::   How to specify which history line to use.
 277 * Word Designators::    Specifying which words are of interest.
 278 * Modifiers::           Modifying the results of substitution.
 279 @end menu
 280
 281 @node Event Designators
 282 @subsection Event Designators
 283 @cindex event designators
 284
 285 An event designator is a reference to a command line entry in the
 286 history list.
 287 @cindex history events
 288
 289 @table @asis
 290
 291 @item @code{!}
 292 Start a history substitution, except when followed by a space, tab,
 293 the end of the line, @samp{=} or @samp{(}.
 294
 295 @item @code{!@var{n}}
 296 Refer to command line @var{n}.
 297
 298 @item @code{!-@var{n}}
 299 Refer to the command @var{n} lines back.
 300
 301 @item @code{!!}
 302 Refer to the previous command.  This is a synonym for @samp{!-1}.
 303
 304 @item @code{!@var{string}}
 305 Refer to the most recent command starting with @var{string}.
 306
 307 @item @code{!?@var{string}[?]}
 308 Refer to the most recent command containing @var{string}.  The trailing
 309 @samp{?} may be omitted if the @var{string} is followed immediately by
 310 a newline.
 311
 312 @item @code{^@var{string1}^@var{string2}^}
 313 Quick Substitution.  Repeat the last command, replacing @var{string1}
 314 with @var{string2}.  Equivalent to
 315 @code{!!:s/@var{string1}/@var{string2}/}.
 316
 317 @item @code{!#}
 318 The entire command line typed so far.
 319
 320 @end table
 321
 322 @node Word Designators
 323 @subsection Word Designators
 324
 325 Word designators are used to select desired words from the event.
 326 A @samp{:} separates the event specification from the word designator.  It
 327 may be omitted if the word designator begins with a @samp{^}, @samp{$},
 328 @samp{*}, @samp{-}, or @samp{%}.  Words are numbered from the beginning
 329 of the line, with the first word being denoted by 0 (zero).  Words are
 330 inserted into the current line separated by single spaces.
 331
 332 @need 0.75
 333 For example,
 334
 335 @table @code
 336 @item !!
 337 designates the preceding command.  When you type this, the preceding
 338 command is repeated in toto.
 339
 340 @item !!:$
 341 designates the last argument of the preceding command.  This may be
 342 shortened to @code{!$}.
 343
 344 @item !fi:2
 345 designates the second argument of the most recent command starting with
 346 the letters @code{fi}.
 347 @end table
 348
 349 @need 0.75
 350 Here are the word designators:
 351
 352 @table @code
 353
 354 @item 0 (zero)
 355 The @code{0}th word.  For many applications, this is the command word.
 356
 357 @item @var{n}
 358 The @var{n}th word.
 359
 360 @item ^
 361 The first argument; that is, word 1.
 362
 363 @item $
 364 The last argument.
 365
 366 @item %
 367 The word matched by the most recent @samp{?@var{string}?} search.
 368
 369 @item @var{x}-@var{y}
 370 A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
 371
 372 @item *
 373 All of the words, except the @code{0}th.  This is a synonym for @samp{1-$}.
 374 It is not an error to use @samp{*} if there is just one word in the event;
 375 the empty string is returned in that case.
 376
 377 @item @var{x}*
 378 Abbreviates @samp{@var{x}-$}
 379
 380 @item @var{x}-
 381 Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
 382
 383 @end table
 384
 385 If a word designator is supplied without an event specification, the
 386 previous command is used as the event.
 387
 388 @node Modifiers
 389 @subsection Modifiers
 390
 391 After the optional word designator, you can add a sequence of one or more
 392 of the following modifiers, each preceded by a @samp{:}.
 393
 394 @table @code
 395
 396 @item h
 397 Remove a trailing pathname component, leaving only the head.
 398
 399 @item t
 400 Remove all leading  pathname  components, leaving the tail.
 401
 402 @item r
 403 Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
 404 the basename.
 405
 406 @item e
 407 Remove all but the trailing suffix.
 408
 409 @item p
 410 Print the new command but do not execute it.
 411
 412 @ifset BashFeatures
 413 @item q
 414 Quote the substituted words, escaping further substitutions.
 415
 416 @item x
 417 Quote the substituted words as with @samp{q},
 418 but break into words at spaces, tabs, and newlines.
 419 @end ifset
 420
 421 @item s/@var{old}/@var{new}/
 422 Substitute @var{new} for the first occurrence of @var{old} in the
 423 event line.  Any delimiter may be used in place of @samp{/}.
 424 The delimiter may be quoted in @var{old} and @var{new}
 425 with a single backslash.  If @samp{&} appears in @var{new},
 426 it is replaced by @var{old}.  A single backslash will quote
 427 the @samp{&}.  The final delimiter is optional if it is the last
 428 character on the input line.
 429
 430 @item &
 431 Repeat the previous substitution.
 432
 433 @item g
 434 Cause changes to be applied over the entire event line.  Used in
 435 conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/},
 436 or with @samp{&}.
 437
 438 @end table