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