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 @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.
  38 @c For
  39 @c information on using the GNU History Library in your own programs,
  40 @c @pxref{Programming with GNU History}.
  41 @end ifclear
  42
  43 @ifset BashFeatures
  44 @menu
  45 * Bash History Facilities::     How Bash lets you manipulate your command
  46                                 history.
  47 * Bash History Builtins::       The Bash builtin commands that manipulate
  48                                 the command history.
  49 * History Interaction::         What it feels like using History as a user.
  50 @end menu
  51 @end ifset
  52 @ifclear BashFeatures
  53 @menu
  54 * History Interaction::         What it feels like using History as a user.
  55 @end menu
  56 @end ifclear
  57
  58 @ifset BashFeatures
  59 @node Bash History Facilities
  60 @section Bash History Facilities
  61 @cindex command history
  62 @cindex history list
  63
  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
  68 @code{HISTSIZE}
  69 commands (default 500) is saved in a history list.  The shell
  70 stores each command in the history list prior to parameter and
  71 variable expansion
  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.
  84 If @code{HISTFILE}
  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.
  89
  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
  96 history list.
  97
  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
 101 commands entered.
 102 The @code{cmdhist}
 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.
 106 The @code{lithist}
 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}.
 110
 111 @node Bash History Builtins
 112 @section Bash History Builtins
 113 @cindex history builtins
 114
 115 Bash provides two builtin commands that allow you to manipulate the
 116 history list and history file.
 117
 118 @table @code
 119
 120 @item fc
 121 @c btindex fc
 122 @example
 123 @code{fc [-e @var{ename}] [-nlr] [@var{first}] [@var{last}]}
 124 @code{fc -s [@var{pat}=@var{rep}] [@var{command}]}
 125 @end example
 126
 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.
 144
 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}.
 147
 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}).
 151
 152 @item history
 153 @c btindex history
 154 @example
 155 history [-c] [@var{n}]
 156 history [-anrw] [@var{filename}]
 157 history -ps @var{arg}
 158 @end example
 159
 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:
 164
 165 @table @code
 166 @item -w
 167 Write out the current history to the history file.
 168
 169 @item -r
 170 Read the current history file and append its contents to
 171 the history list.
 172
 173 @item -a
 174 Append the new
 175 history lines (history lines entered since the beginning of the
 176 current Bash session) to the history file.
 177
 178 @item -n
 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.
 182
 183 @item -c
 184 Clear the history list.  This may be combined
 185 with the other options to replace the history list completely.
 186
 187 @item -s
 188 The @var{arg}s are added to the end of
 189 the history list as a single entry.
 190
 191 @item -p
 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.
 194 @end table
 195
 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.
 200
 201 @end table
 202 @end ifset
 203
 204 @node History Interaction
 205 @section History Expansion
 206 @cindex history expansion
 207
 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.
 211
 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.
 216
 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.
 228 @ifset BashFeatures
 229 Only @samp{\} and @samp{'} may be used to escape the history expansion
 230 character.
 231 @end ifset
 232
 233 @ifset BashFeatures
 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
 239 the shell parser.
 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.
 251
 252 The shell allows control of the various characters used by the
 253 history expansion mechanism with the @code{histchars} variable.
 254 @end ifset
 255
 256 @menu
 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.
 260 @end menu
 261
 262 @node Event Designators
 263 @subsection Event Designators
 264 @cindex event designators
 265
 266 An event designator is a reference to a command line entry in the
 267 history list.
 268 @cindex history events
 269
 270 @table @asis
 271
 272 @item @code{!}
 273 Start a history substitution, except when followed by a space, tab,
 274 the end of the line, @samp{=} or @samp{(}.
 275
 276 @item @code{!@var{n}}
 277 Refer to command line @var{n}.
 278
 279 @item @code{!-@var{n}}
 280 Refer to the command @var{n} lines back.
 281
 282 @item @code{!!}
 283 Refer to the previous command.  This is a synonym for @samp{!-1}.
 284
 285 @item @code{!@var{string}}
 286 Refer to the most recent command starting with @var{string}.
 287
 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
 291 a newline.
 292
 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}/}.
 297
 298 @item @code{!#}
 299 The entire command line typed so far.
 300
 301 @end table
 302
 303 @node Word Designators
 304 @subsection Word Designators
 305
 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.
 312
 313 @table @code
 314
 315 @item 0 (zero)
 316 The @code{0}th word.  For many applications, this is the command word.
 317
 318 @item @var{n}
 319 The @var{n}th word.
 320
 321 @item ^
 322 The first argument; that is, word 1.
 323
 324 @item $
 325 The last argument.
 326
 327 @item %
 328 The word matched by the most recent @samp{?@var{string}?} search.
 329
 330 @item @var{x}-@var{y}
 331 A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
 332
 333 @item *
 334 All of the words, except the @code{0}th.  This is a synonym for @samp{1-$}.
 335 It is not an error to use @samp{*} if there is just one word in the event;
 336 the empty string is returned in that case.
 337
 338 @item @var{x}*
 339 Abbreviates @samp{@var{x}-$}
 340
 341 @item @var{x}-
 342 Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
 343
 344 @end table
 345
 346 If a word designator is supplied without an event specification, the
 347 previous command is used as the event.
 348
 349 @node Modifiers
 350 @subsection Modifiers
 351
 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{:}.
 354
 355 @table @code
 356
 357 @item h
 358 Remove a trailing pathname component, leaving only the head.
 359
 360 @item t
 361 Remove all leading  pathname  components, leaving the tail.
 362
 363 @item r
 364 Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
 365 the basename.
 366
 367 @item e
 368 Remove all but the trailing suffix.
 369
 370 @item p
 371 Print the new command but do not execute it.
 372
 373 @ifset BashFeatures
 374 @item q
 375 Quote the substituted words, escaping further substitutions.
 376
 377 @item x
 378 Quote the substituted words as with @samp{q},
 379 but break into words at spaces, tabs, and newlines.
 380 @end ifset
 381
 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.
 390
 391 @item &
 392 Repeat the previous substitution.
 393
 394 @item g
 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}/},
 397 or with @samp{&}.
 398
 399 @end table