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 your own 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 * History Interaction::         What it feels like using History as a user.
  47 @end menu
  48 @end ifset
  49 @ifclear BashFeatures
  50 @menu
  51 * History Interaction::         What it feels like using History as a user.
  52 @end menu
  53 @end ifclear
  54
  55 @ifset BashFeatures
  56 @node Bash History Facilities
  57 @section Bash History Facilities
  58 @cindex command history
  59 @cindex history list
  60
  61 When the @samp{-o history} option to the @code{set} builtin
  62 is enabled (@pxref{The Set Builtin}),
  63 the shell provides access to the @var{command history},
  64 the list of commands previously typed.  The text of the last
  65 @code{HISTSIZE}
  66 commands (default 500) is saved in a history list.  The shell
  67 stores each command in the history list prior to parameter and
  68 variable expansion
  69 but after history expansion is performed, subject to the
  70 values of the shell variables
  71 @code{HISTIGNORE} and @code{HISTCONTROL}.
  72 When the shell starts up, the history is initialized from the
  73 file named by the @code{HISTFILE} variable (default @file{~/.bash_history}).
  74 @code{HISTFILE} is truncated, if necessary, to contain no more than
  75 the number of lines specified by the value of the @code{HISTFILESIZE}
  76 variable.  When an interactive shell exits, the last
  77 @code{HISTSIZE} lines are copied from the history list to @code{HISTFILE}.
  78 If the @code{histappend} shell option is set (@pxref{Bash Builtins}),
  79 the lines are appended to the history file,
  80 otherwise the history file is overwritten.
  81 If @code{HISTFILE}
  82 is unset, or if the history file is unwritable, the history is
  83 not saved.  After saving the history, the history file is truncated
  84 to contain no more than @code{$HISTFILESIZE}
  85 lines.  If @code{HISTFILESIZE} is not set, no truncation is performed.
  86
  87 The builtin command @code{fc} (@pxref{Korn Shell Builtins})
  88 may be used to list or edit and re-execute a portion of
  89 the history list.  The @code{history} builtin (@pxref{C Shell Builtins})
  90 can be used to display or modify the history list and
  91 manipulate the history file.
  92 When using the command-line editing, search commands
  93 are available in each editing mode that provide access to the
  94 history list.
  95
  96 The shell allows control over which commands are saved on the history
  97 list.  The @code{HISTCONTROL} and @code{HISTIGNORE}
  98 variables may be set to cause the shell to save only a subset of the
  99 commands entered.
 100 The @code{cmdhist}
 101 shell option, if enabled, causes the shell to attempt to save each
 102 line of a multi-line command in the same history entry, adding
 103 semicolons where necessary to preserve syntactic correctness.
 104 The @code{lithist}
 105 shell option causes the shell to save the command with embedded newlines
 106 instead of semicolons.
 107 @xref{Bash Builtins} for a description of @code{shopt}.
 108 @end ifset
 109
 110 @node History Interaction
 111 @section Interactive History Expansion
 112 @cindex history expansion
 113
 114 The History library provides a history expansion feature that is similar
 115 to the history expansion provided by @code{csh}.  This section
 116 describes the syntax used to manipulate the history information.
 117
 118 History expansions introduce words from the history list into
 119 the input stream, making it easy to repeat commands, insert the
 120 arguments to a previous command into the current input line, or
 121 fix errors in previous commands quickly.
 122
 123 History expansion takes place in two parts.  The first is to determine
 124 which line from the previous history should be used during substitution.
 125 The second is to select portions of that line for inclusion into the
 126 current one.  The line selected from the previous history is called the
 127 @dfn{event}, and the portions of that line that are acted upon are
 128 called @dfn{words}.  Various @dfn{modifiers} are available to manipulate
 129 the selected words.  The line is broken into words in the same fashion
 130 that Bash does, so that several English (or Unix) words
 131 surrounded by quotes are considered as one word.
 132 History expansions are introduced by the appearance of the
 133 history expansion character, which is @samp{!} by default.
 134 @ifset BashFeatures
 135 Only @samp{\} and @samp{'} may be used to escape the history expansion
 136 character.
 137 @end ifset
 138
 139 @ifset BashFeatures
 140 Several shell options settable with the @code{shopt}
 141 builtin (@pxref{Bash Builtins}) may be used to tailor
 142 the behavior of history expansion.  If the
 143 @code{histverify} shell option is enabled, and Readline
 144 is being used, history substitutions are not immediately passed to
 145 the shell parser.
 146 Instead, the expanded line is reloaded into the Readline
 147 editing buffer for further modification.
 148 If Readline is being used, and the @code{histreedit}
 149 shell option is enabled, a failed history expansion will be
 150 reloaded into the Readline editing buffer for correction.
 151 The @samp{-p} option to the @code{history} builtin command
 152 may be used to see what a history expansion will do before using it.
 153 The @samp{-s} option to the @code{history} builtin may be used to
 154 add commands to the end of the history list without actually executing
 155 them, so that they are available for subsequent recall.
 156
 157 The shell allows control of the various characters used by the
 158 history expansion mechanism with the @code{histchars} variable.
 159 @end ifset
 160
 161 @menu
 162 * Event Designators::   How to specify which history line to use.
 163 * Word Designators::    Specifying which words are of interest.
 164 * Modifiers::           Modifying the results of substitution.
 165 @end menu
 166
 167 @node Event Designators
 168 @subsection Event Designators
 169 @cindex event designators
 170
 171 An event designator is a reference to a command line entry in the
 172 history list.
 173 @cindex history events
 174
 175 @table @asis
 176
 177 @item @code{!}
 178 Start a history substitution, except when followed by a space, tab,
 179 the end of the line, @key{=} or @key{(}.
 180
 181 @item @code{!@var{n}}
 182 Refer to command line @var{n}.
 183
 184 @item @code{!-@var{n}}
 185 Refer to the command @var{n} lines back.
 186
 187 @item @code{!!}
 188 Refer to the previous command.  This is a synonym for @samp{!-1}.
 189
 190 @item @code{!@var{string}}
 191 Refer to the most recent command starting with @var{string}.
 192
 193 @item @code{!?@var{string}[?]}
 194 Refer to the most recent command containing @var{string}.  The trailing
 195 @samp{?} may be omitted if the @var{string} is followed immediately by
 196 a newline.
 197
 198 @item @code{^@var{string1}^@var{string2}^}
 199 Quick Substitution.  Repeat the last command, replacing @var{string1}
 200 with @var{string2}.  Equivalent to
 201 @code{!!:s/@var{string1}/@var{string2}/}.
 202
 203 @item @code{!#}
 204 The entire command line typed so far.
 205
 206 @end table
 207
 208 @node Word Designators
 209 @subsection Word Designators
 210
 211 Word designators are used to select desired words from the event.
 212 A @samp{:} separates the event specification from the word designator.  It
 213 can be omitted if the word designator begins with a @samp{^}, @samp{$},
 214 @samp{*}, @samp{-}, or @samp{%}.  Words are numbered from the beginning
 215 of the line, with the first word being denoted by 0 (zero).  Words are
 216 inserted into the current line separated by single spaces.
 217
 218 @table @code
 219
 220 @item 0 (zero)
 221 The @code{0}th word.  For many applications, this is the command word.
 222
 223 @item @var{n}
 224 The @var{n}th word.
 225
 226 @item ^
 227 The first argument; that is, word 1.
 228
 229 @item $
 230 The last argument.
 231
 232 @item %
 233 The word matched by the most recent @samp{?@var{string}?} search.
 234
 235 @item @var{x}-@var{y}
 236 A range of words; @samp{-@var{y}} abbreviates @samp{0-@var{y}}.
 237
 238 @item *
 239 All of the words, except the @code{0}th.  This is a synonym for @samp{1-$}.
 240 It is not an error to use @samp{*} if there is just one word in the event;
 241 the empty string is returned in that case.
 242
 243 @item @var{x}*
 244 Abbreviates @samp{@var{x}-$}
 245
 246 @item @var{x}-
 247 Abbreviates @samp{@var{x}-$} like @samp{@var{x}*}, but omits the last word.
 248
 249 @end table
 250
 251 If a word designator is supplied without an event specification, the
 252 previous command is used as the event.
 253
 254 @node Modifiers
 255 @subsection Modifiers
 256
 257 After the optional word designator, you can add a sequence of one or more
 258 of the following modifiers, each preceded by a @samp{:}.
 259
 260 @table @code
 261
 262 @item h
 263 Remove a trailing pathname component, leaving only the head.
 264
 265 @item t
 266 Remove all leading  pathname  components, leaving the tail.
 267
 268 @item r
 269 Remove a trailing suffix of the form @samp{.@var{suffix}}, leaving
 270 the basename.
 271
 272 @item e
 273 Remove all but the trailing suffix.
 274
 275 @item p
 276 Print the new command but do not execute it.
 277
 278 @ifset BashFeatures
 279 @item q
 280 Quote the substituted words, escaping further substitutions.
 281
 282 @item x
 283 Quote the substituted words as with @samp{q},
 284 but break into words at spaces, tabs, and newlines.
 285 @end ifset
 286
 287 @item s/@var{old}/@var{new}/
 288 Substitute @var{new} for the first occurrence of @var{old} in the
 289 event line.  Any delimiter may be used in place of @samp{/}.
 290 The delimiter may be quoted in @var{old} and @var{new}
 291 with a single backslash.  If @samp{&} appears in @var{new},
 292 it is replaced by @var{old}.  A single backslash will quote
 293 the @samp{&}.  The final delimiter is optional if it is the last
 294 character on the input line.
 295
 296 @item &
 297 Repeat the previous substitution.
 298
 299 @item g
 300 Cause changes to be applied over the entire event line.  Used in
 301 conjunction with @samp{s}, as in @code{gs/@var{old}/@var{new}/},
 302 or with @samp{&}.
 303
 304 @end table