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