readline/history.texi

   1 \input texinfo.tex
   2 @setfilename history.info
   3
   4 @ifinfo
   5 @format
   6 START-INFO-DIR-ENTRY
   7 * History: (history).           The GNU History library.
   8 END-INFO-DIR-ENTRY
   9 @end format
  10 @end ifinfo
  11
  12 @ifinfo
  13 This file documents the GNU History library.
  14
  15 Copyright (C) 1988 Free Software Foundation, Inc.
  16 Authored by Brian Fox.
  17
  18 Permission is granted to make and distribute verbatim copies of this manual
  19 provided the copyright notice and this permission notice are preserved on
  20 all copies.
  21
  22 @ignore
  23 Permission is granted to process this file through Tex and print the
  24 results, provided the printed document carries copying permission notice
  25 identical to this one except for the removal of this paragraph (this
  26 paragraph not being relevant to the printed manual).
  27 @end ignore
  28
  29 Permission is granted to copy and distribute modified versions of this
  30 manual under the conditions for verbatim copying, provided also that the
  31 GNU Copyright statement is available to the distributee, and provided that
  32 the entire resulting derived work is distributed under the terms of a
  33 permission notice identical to this one.
  34
  35 Permission is granted to copy and distribute translations of this manual
  36 into another language, under the above conditions for modified versions.
  37 @end ifinfo
  38
  39 @node Top, Introduction, , (DIR)
  40
  41 This document describes the GNU History library, a programming tool that
  42 provides a consistent user interface for recalling lines of previously
  43 typed input.
  44
  45 @menu
  46 * Introduction::        What is the GNU History library for?
  47 * Interactive Use::     What it feels like using History as a user.
  48 * Programming::         How to use History in your programs.
  49 @end menu
  50
  51 @node Introduction, Interactive Use, Top, Top
  52 @unnumbered Introduction
  53
  54 Many programs read input from the user a line at a time.  The GNU history
  55 library is able to keep track of those lines, associate arbitrary data with
  56 each line, and utilize information from previous lines in making up new
  57 ones.
  58
  59 The programmer using the History library has available to him functions for
  60 remembering lines on a history stack, associating arbitrary data with a
  61 line, removing lines from the stack, searching through the stack for a
  62 line containing an arbitrary text string, and referencing any line on the
  63 stack directly.  In addition, a history @dfn{expansion} function is
  64 available which provides for a consistent user interface across many
  65 different programs.
  66
  67 The end-user using programs written with the History library has the
  68 benifit of a consistent user interface, with a set of well-known commands
  69 for manipulating the text of previous lines and using that text in new
  70 commands.  The basic history manipulation commands are similar to the
  71 history substitution used by Csh.
  72
  73 If the programmer desires, he can use the Readline library, which includes
  74 history manipulation by default, and has the added advantage of Emacs style
  75 command line editing.
  76
  77 @node Interactive Use, Programming, Introduction, Top
  78 @chapter Interactive Use
  79
  80 @section History Expansion
  81 @cindex expansion
  82
  83 The History library provides a history expansion feature that is similar to
  84 the history expansion in Csh.  The following text describes what syntax
  85 features are available.
  86
  87 History expansion takes place in two parts.  The first is to determine
  88 which line from the previous history should be used during substitution.
  89 The second is to select portions of that line for inclusion into the
  90 current one.  The line selected from the previous history is called the
  91 @dfn{event}, and the portions of that line that are acted upon are called
  92 @dfn{words}.  The line is broken into words in the same fashion that the
  93 Bash shell does, so that several English (or Unix) words surrounded by
  94 quotes are considered as one word.
  95
  96 @menu
  97 * Event Designators::   How to specify which history line to use.
  98 * Word Designators::    Specifying which words are of interest.
  99 * Modifiers::           Modifying the results of susbstitution.
 100 @end menu
 101
 102 @node Event Designators, Word Designators, , Interactive Use
 103 @subsection Event Designators
 104 @cindex event designators
 105
 106 An event designator is a reference to a command line entry in the history
 107 list.
 108
 109 @table @var
 110
 111 @item !
 112 Start a history subsititution, except when followed by a @key{SPC},
 113 @key{TAB}, @key{RET}, @key{=} or @key{(}.
 114
 115 @item !!
 116 Refer to the previous command.  This is a synonym for @code{!-1}.
 117
 118 @item !n
 119 Refer to command line @var{n}.
 120
 121 @item !-n
 122 Refer to the current command line minus @var{n}.
 123
 124 @item !string
 125 Refer to the most recent command starting with @var{string}.
 126
 127 @item !?string[?]
 128 Refer to the most recent command containing @var{string}.
 129
 130 @end table
 131
 132 @node Word Designators, Modifiers, Event Designators, Interactive Use
 133 @subsection Word Designators
 134
 135 A @key{:} separates the event specification from the word designator.  It
 136 can be omitted if the word designator begins with a @key{^}, @key{$},
 137 @key{*} or @key{%}.  Words are numbered from the beginning of the line,
 138 with the first word being denoted by a 0 (zero).
 139
 140 @table @asis
 141
 142 @item @var{0} (zero)
 143 The zero'th word.  For many applications, this is the command word.
 144
 145 @item n
 146 The @var{n}'th word.
 147
 148 @item @var{^}
 149 The first argument.  that is, word 1.
 150
 151 @item @var{$}
 152 The last argument.
 153
 154 @item @var{%}
 155 The word matched by the most recent @code{?string?} search.
 156
 157 @item @var{x}-@var{y}
 158 A range of words; @code{-@var{y}} is equivalent to @code{0-@var{y}}.
 159
 160 @item @var{*}
 161 All of the words, excepting the zero'th.  This is a synonym for @samp{1-$}.
 162 It is not an error to use @samp{*} if there is just one word in the event.
 163 The empty string is returned in that case.
 164
 165 @end table
 166
 167 @node Modifiers, , Word Designators, Interactive Use
 168 @subsection Modifiers
 169
 170 After the optional word designator, you can add a sequence of one or more
 171 of the following modifiers, each preceded by a @key{:}.
 172
 173 @table @code
 174
 175 @item #
 176 The entire command line typed so far.  This means the current command,
 177 not the previous command, so it really isn't a word designator, and doesn't
 178 belong in this section.
 179
 180 @item h
 181 Remove a trailing pathname component, leaving only the head.
 182
 183 @item r
 184 Remove a trailing suffix of the form ".xxx", leaving the basename (root).
 185
 186 @item e
 187 Remove all but the suffix (end).
 188
 189 @item t
 190 Remove all leading  pathname  components (before the last slash), leaving
 191 the tail.
 192
 193 @item p
 194 Print the new command but do not execute it.  This takes effect
 195 immediately, so it should be the last specifier on the line.
 196
 197 @end table
 198
 199 @node Programming, , Interactive Use, Top
 200 @chapter Programming
 201
 202 @bye