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