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| <TITLE>GNU History Library</TITLE> |
| </HEAD> |
| <BODY> |
| <H1>GNU History Library</H1> |
| <H2>Edition 4.0, for <CODE>History Library</CODE> Version 4.0.</H2> |
| <H2>December 1998</H2> |
| <ADDRESS>Brian Fox, Free Software Foundation</ADDRESS> |
| <ADDRESS>Chet Ramey, Case Western Reserve University</ADDRESS> |
| <P> |
| <P><HR><P> |
| <H1>Table of Contents</H1> |
| <UL> |
| <LI><A NAME="TOC1" HREF="history.html#SEC1">Using History Interactively</A> |
| <UL> |
| <LI><A NAME="TOC2" HREF="history.html#SEC2">History Expansion</A> |
| <UL> |
| <LI><A NAME="TOC3" HREF="history.html#SEC3">Event Designators</A> |
| <LI><A NAME="TOC4" HREF="history.html#SEC4">Word Designators</A> |
| <LI><A NAME="TOC5" HREF="history.html#SEC5">Modifiers</A> |
| </UL> |
| </UL> |
| <LI><A NAME="TOC6" HREF="history.html#SEC6">Programming with GNU History</A> |
| <UL> |
| <LI><A NAME="TOC7" HREF="history.html#SEC7">Introduction to History</A> |
| <LI><A NAME="TOC8" HREF="history.html#SEC8">History Storage</A> |
| <LI><A NAME="TOC9" HREF="history.html#SEC9">History Functions</A> |
| <UL> |
| <LI><A NAME="TOC10" HREF="history.html#SEC10">Initializing History and State Management</A> |
| <LI><A NAME="TOC11" HREF="history.html#SEC11">History List Management</A> |
| <LI><A NAME="TOC12" HREF="history.html#SEC12">Information About the History List</A> |
| <LI><A NAME="TOC13" HREF="history.html#SEC13">Moving Around the History List</A> |
| <LI><A NAME="TOC14" HREF="history.html#SEC14">Searching the History List</A> |
| <LI><A NAME="TOC15" HREF="history.html#SEC15">Managing the History File</A> |
| <LI><A NAME="TOC16" HREF="history.html#SEC16">History Expansion</A> |
| </UL> |
| <LI><A NAME="TOC17" HREF="history.html#SEC17">History Variables</A> |
| <LI><A NAME="TOC18" HREF="history.html#SEC18">History Programming Example</A> |
| </UL> |
| <LI><A NAME="TOC19" HREF="history.html#SEC19">Concept Index</A> |
| <LI><A NAME="TOC20" HREF="history.html#SEC20">Function and Variable Index</A> |
| </UL> |
| <P><HR><P> |
| |
| <P> |
| This document describes the GNU History library, a programming tool that |
| provides a consistent user interface for recalling lines of previously |
| typed input. |
| |
| </P> |
| <P> |
| Published by the Free Software Foundation <BR> |
| 675 Massachusetts Avenue, <BR> |
| Cambridge, MA 02139 USA |
| |
| </P> |
| <P> |
| Permission is granted to make and distribute verbatim copies of |
| this manual provided the copyright notice and this permission notice |
| are preserved on all copies. |
| |
| </P> |
| <P> |
| Permission is granted to copy and distribute modified versions of this |
| manual under the conditions for verbatim copying, provided that the entire |
| resulting derived work is distributed under the terms of a permission |
| notice identical to this one. |
| |
| </P> |
| <P> |
| Permission is granted to copy and distribute translations of this manual |
| into another language, under the above conditions for modified versions, |
| except that this permission notice may be stated in a translation approved |
| by the Free Software Foundation. |
| |
| </P> |
| <P> |
| Copyright (C) 1988-1999 Free Software Foundation, Inc. |
| |
| </P> |
| |
| |
| |
| <H1><A NAME="SEC1" HREF="history.html#TOC1">Using History Interactively</A></H1> |
| |
| <P> |
| This chapter describes how to use the GNU History Library interactively, |
| from a user's standpoint. It should be considered a user's guide. For |
| information on using the GNU History Library in your own programs, |
| see section <A HREF="history.html#SEC6">Programming with GNU History</A>. |
| |
| </P> |
| |
| <UL> |
| <LI><A HREF="history.html#SEC2">History Interaction</A>: What it feels like using History as a user. |
| </UL> |
| |
| |
| |
| <H2><A NAME="SEC2" HREF="history.html#TOC2">History Expansion</A></H2> |
| <P> |
| <A NAME="IDX1"></A> |
| |
| </P> |
| <P> |
| The History library provides a history expansion feature that is similar |
| to the history expansion provided by <CODE>csh</CODE>. This section |
| describes the syntax used to manipulate the history information. |
| |
| </P> |
| <P> |
| History expansions introduce words from the history list into |
| the input stream, making it easy to repeat commands, insert the |
| arguments to a previous command into the current input line, or |
| fix errors in previous commands quickly. |
| |
| </P> |
| <P> |
| History expansion takes place in two parts. The first is to determine |
| which line from the history list should be used during substitution. |
| The second is to select portions of that line for inclusion into the |
| current one. The line selected from the history is called the |
| <EM>event</EM>, and the portions of that line that are acted upon are |
| called <EM>words</EM>. Various <EM>modifiers</EM> are available to manipulate |
| the selected words. The line is broken into words in the same fashion |
| that Bash does, so that several words |
| surrounded by quotes are considered one word. |
| History expansions are introduced by the appearance of the |
| history expansion character, which is <SAMP>`!'</SAMP> by default. |
| |
| </P> |
| |
| |
| <UL> |
| <LI><A HREF="history.html#SEC3">Event Designators</A>: How to specify which history line to use. |
| <LI><A HREF="history.html#SEC4">Word Designators</A>: Specifying which words are of interest. |
| <LI><A HREF="history.html#SEC5">Modifiers</A>: Modifying the results of substitution. |
| </UL> |
| |
| |
| |
| <H3><A NAME="SEC3" HREF="history.html#TOC3">Event Designators</A></H3> |
| <P> |
| <A NAME="IDX2"></A> |
| |
| </P> |
| <P> |
| An event designator is a reference to a command line entry in the |
| history list. |
| <A NAME="IDX3"></A> |
| |
| </P> |
| <DL COMPACT> |
| |
| <DT><CODE>!</CODE> |
| <DD> |
| Start a history substitution, except when followed by a space, tab, |
| the end of the line, <SAMP>`='</SAMP> or <SAMP>`('</SAMP>. |
| |
| <DT><CODE>!<VAR>n</VAR></CODE> |
| <DD> |
| Refer to command line <VAR>n</VAR>. |
| |
| <DT><CODE>!-<VAR>n</VAR></CODE> |
| <DD> |
| Refer to the command <VAR>n</VAR> lines back. |
| |
| <DT><CODE>!!</CODE> |
| <DD> |
| Refer to the previous command. This is a synonym for <SAMP>`!-1'</SAMP>. |
| |
| <DT><CODE>!<VAR>string</VAR></CODE> |
| <DD> |
| Refer to the most recent command starting with <VAR>string</VAR>. |
| |
| <DT><CODE>!?<VAR>string</VAR>[?]</CODE> |
| <DD> |
| Refer to the most recent command containing <VAR>string</VAR>. The trailing |
| <SAMP>`?'</SAMP> may be omitted if the <VAR>string</VAR> is followed immediately by |
| a newline. |
| |
| <DT><CODE>^<VAR>string1</VAR>^<VAR>string2</VAR>^</CODE> |
| <DD> |
| Quick Substitution. Repeat the last command, replacing <VAR>string1</VAR> |
| with <VAR>string2</VAR>. Equivalent to |
| <CODE>!!:s/<VAR>string1</VAR>/<VAR>string2</VAR>/</CODE>. |
| |
| <DT><CODE>!#</CODE> |
| <DD> |
| The entire command line typed so far. |
| |
| </DL> |
| |
| |
| |
| <H3><A NAME="SEC4" HREF="history.html#TOC4">Word Designators</A></H3> |
| |
| <P> |
| Word designators are used to select desired words from the event. |
| A <SAMP>`:'</SAMP> separates the event specification from the word designator. It |
| may be omitted if the word designator begins with a <SAMP>`^'</SAMP>, <SAMP>`$'</SAMP>, |
| <SAMP>`*'</SAMP>, <SAMP>`-'</SAMP>, or <SAMP>`%'</SAMP>. Words are numbered from the beginning |
| of the line, with the first word being denoted by 0 (zero). Words are |
| inserted into the current line separated by single spaces. |
| |
| </P> |
| <DL COMPACT> |
| |
| <DT><CODE>0 (zero)</CODE> |
| <DD> |
| The <CODE>0</CODE>th word. For many applications, this is the command word. |
| |
| <DT><CODE><VAR>n</VAR></CODE> |
| <DD> |
| The <VAR>n</VAR>th word. |
| |
| <DT><CODE>^</CODE> |
| <DD> |
| The first argument; that is, word 1. |
| |
| <DT><CODE>$</CODE> |
| <DD> |
| The last argument. |
| |
| <DT><CODE>%</CODE> |
| <DD> |
| The word matched by the most recent <SAMP>`?<VAR>string</VAR>?'</SAMP> search. |
| |
| <DT><CODE><VAR>x</VAR>-<VAR>y</VAR></CODE> |
| <DD> |
| A range of words; <SAMP>`-<VAR>y</VAR>'</SAMP> abbreviates <SAMP>`0-<VAR>y</VAR>'</SAMP>. |
| |
| <DT><CODE>*</CODE> |
| <DD> |
| All of the words, except the <CODE>0</CODE>th. This is a synonym for <SAMP>`1-$'</SAMP>. |
| It is not an error to use <SAMP>`*'</SAMP> if there is just one word in the event; |
| the empty string is returned in that case. |
| |
| <DT><CODE><VAR>x</VAR>*</CODE> |
| <DD> |
| Abbreviates <SAMP>`<VAR>x</VAR>-$'</SAMP> |
| |
| <DT><CODE><VAR>x</VAR>-</CODE> |
| <DD> |
| Abbreviates <SAMP>`<VAR>x</VAR>-$'</SAMP> like <SAMP>`<VAR>x</VAR>*'</SAMP>, but omits the last word. |
| |
| </DL> |
| |
| <P> |
| If a word designator is supplied without an event specification, the |
| previous command is used as the event. |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC5" HREF="history.html#TOC5">Modifiers</A></H3> |
| |
| <P> |
| After the optional word designator, you can add a sequence of one or more |
| of the following modifiers, each preceded by a <SAMP>`:'</SAMP>. |
| |
| </P> |
| <DL COMPACT> |
| |
| <DT><CODE>h</CODE> |
| <DD> |
| Remove a trailing pathname component, leaving only the head. |
| |
| <DT><CODE>t</CODE> |
| <DD> |
| Remove all leading pathname components, leaving the tail. |
| |
| <DT><CODE>r</CODE> |
| <DD> |
| Remove a trailing suffix of the form <SAMP>`.<VAR>suffix</VAR>'</SAMP>, leaving |
| the basename. |
| |
| <DT><CODE>e</CODE> |
| <DD> |
| Remove all but the trailing suffix. |
| |
| <DT><CODE>p</CODE> |
| <DD> |
| Print the new command but do not execute it. |
| |
| <DT><CODE>s/<VAR>old</VAR>/<VAR>new</VAR>/</CODE> |
| <DD> |
| Substitute <VAR>new</VAR> for the first occurrence of <VAR>old</VAR> in the |
| event line. Any delimiter may be used in place of <SAMP>`/'</SAMP>. |
| The delimiter may be quoted in <VAR>old</VAR> and <VAR>new</VAR> |
| with a single backslash. If <SAMP>`&'</SAMP> appears in <VAR>new</VAR>, |
| it is replaced by <VAR>old</VAR>. A single backslash will quote |
| the <SAMP>`&'</SAMP>. The final delimiter is optional if it is the last |
| character on the input line. |
| |
| <DT><CODE>&</CODE> |
| <DD> |
| Repeat the previous substitution. |
| |
| <DT><CODE>g</CODE> |
| <DD> |
| Cause changes to be applied over the entire event line. Used in |
| conjunction with <SAMP>`s'</SAMP>, as in <CODE>gs/<VAR>old</VAR>/<VAR>new</VAR>/</CODE>, |
| or with <SAMP>`&'</SAMP>. |
| |
| </DL> |
| |
| |
| |
| <H1><A NAME="SEC6" HREF="history.html#TOC6">Programming with GNU History</A></H1> |
| |
| <P> |
| This chapter describes how to interface programs that you write |
| with the GNU History Library. |
| It should be considered a technical guide. |
| For information on the interactive use of GNU History, see section <A HREF="history.html#SEC1">Using History Interactively</A>. |
| |
| </P> |
| |
| <UL> |
| <LI><A HREF="history.html#SEC7">Introduction to History</A>: What is the GNU History library for? |
| <LI><A HREF="history.html#SEC8">History Storage</A>: How information is stored. |
| <LI><A HREF="history.html#SEC9">History Functions</A>: Functions that you can use. |
| <LI><A HREF="history.html#SEC17">History Variables</A>: Variables that control behaviour. |
| <LI><A HREF="history.html#SEC18">History Programming Example</A>: Example of using the GNU History Library. |
| </UL> |
| |
| |
| |
| <H2><A NAME="SEC7" HREF="history.html#TOC7">Introduction to History</A></H2> |
| |
| <P> |
| Many programs read input from the user a line at a time. The GNU History |
| library is able to keep track of those lines, associate arbitrary data with |
| each line, and utilize information from previous lines in composing new |
| ones. |
| |
| </P> |
| <P> |
| The programmer using the History library has available functions |
| for remembering lines on a history list, associating arbitrary data |
| with a line, removing lines from the list, searching through the list |
| for a line containing an arbitrary text string, and referencing any line |
| in the list directly. In addition, a history <EM>expansion</EM> function |
| is available which provides for a consistent user interface across |
| different programs. |
| |
| </P> |
| <P> |
| The user using programs written with the History library has the |
| benefit of a consistent user interface with a set of well-known |
| commands for manipulating the text of previous lines and using that text |
| in new commands. The basic history manipulation commands are similar to |
| the history substitution provided by <CODE>csh</CODE>. |
| |
| </P> |
| <P> |
| If the programmer desires, he can use the Readline library, which |
| includes some history manipulation by default, and has the added |
| advantage of command line editing. |
| |
| </P> |
| |
| |
| <H2><A NAME="SEC8" HREF="history.html#TOC8">History Storage</A></H2> |
| |
| <P> |
| The history list is an array of history entries. A history entry is |
| declared as follows: |
| |
| </P> |
| |
| <PRE> |
| typedef struct _hist_entry { |
| char *line; |
| char *data; |
| } HIST_ENTRY; |
| </PRE> |
| |
| <P> |
| The history list itself might therefore be declared as |
| |
| </P> |
| |
| <PRE> |
| HIST_ENTRY **the_history_list; |
| </PRE> |
| |
| <P> |
| The state of the History library is encapsulated into a single structure: |
| |
| </P> |
| |
| <PRE> |
| /* A structure used to pass the current state of the history stuff around. */ |
| typedef struct _hist_state { |
| HIST_ENTRY **entries; /* Pointer to the entries themselves. */ |
| int offset; /* The location pointer within this array. */ |
| int length; /* Number of elements within this array. */ |
| int size; /* Number of slots allocated to this array. */ |
| int flags; |
| } HISTORY_STATE; |
| </PRE> |
| |
| <P> |
| If the flags member includes <CODE>HS_STIFLED</CODE>, the history has been |
| stifled. |
| |
| </P> |
| |
| |
| <H2><A NAME="SEC9" HREF="history.html#TOC9">History Functions</A></H2> |
| |
| <P> |
| This section describes the calling sequence for the various functions |
| present in GNU History. |
| |
| </P> |
| |
| <UL> |
| <LI><A HREF="history.html#SEC10">Initializing History and State Management</A>: Functions to call when you |
| want to use history in a |
| program. |
| <LI><A HREF="history.html#SEC11">History List Management</A>: Functions used to manage the list |
| of history entries. |
| <LI><A HREF="history.html#SEC12">Information About the History List</A>: Functions returning information about |
| the history list. |
| <LI><A HREF="history.html#SEC13">Moving Around the History List</A>: Functions used to change the position |
| in the history list. |
| <LI><A HREF="history.html#SEC14">Searching the History List</A>: Functions to search the history list |
| for entries containing a string. |
| <LI><A HREF="history.html#SEC15">Managing the History File</A>: Functions that read and write a file |
| containing the history list. |
| <LI><A HREF="history.html#SEC16">History Expansion</A>: Functions to perform csh-like history |
| expansion. |
| </UL> |
| |
| |
| |
| <H3><A NAME="SEC10" HREF="history.html#TOC10">Initializing History and State Management</A></H3> |
| |
| <P> |
| This section describes functions used to initialize and manage |
| the state of the History library when you want to use the history |
| functions in your program. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> void <B>using_history</B> <I>()</I> |
| <DD><A NAME="IDX4"></A> |
| Begin a session in which the history functions might be used. This |
| initializes the interactive variables. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HISTORY_STATE * <B>history_get_history_state</B> <I>()</I> |
| <DD><A NAME="IDX5"></A> |
| Return a structure describing the current state of the input history. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> void <B>history_set_history_state</B> <I>(HISTORY_STATE *state)</I> |
| <DD><A NAME="IDX6"></A> |
| Set the state of the history list according to <VAR>state</VAR>. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC11" HREF="history.html#TOC11">History List Management</A></H3> |
| |
| <P> |
| These functions manage individual entries on the history list, or set |
| parameters managing the list itself. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> void <B>add_history</B> <I>(char *string)</I> |
| <DD><A NAME="IDX7"></A> |
| Place <VAR>string</VAR> at the end of the history list. The associated data |
| field (if any) is set to <CODE>NULL</CODE>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>remove_history</B> <I>(int which)</I> |
| <DD><A NAME="IDX8"></A> |
| Remove history entry at offset <VAR>which</VAR> from the history. The |
| removed element is returned so you can free the line, data, |
| and containing structure. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>replace_history_entry</B> <I>(int which, char *line, char *data)</I> |
| <DD><A NAME="IDX9"></A> |
| Make the history entry at offset <VAR>which</VAR> have <VAR>line</VAR> and <VAR>data</VAR>. |
| This returns the old entry so you can dispose of the data. In the case |
| of an invalid <VAR>which</VAR>, a <CODE>NULL</CODE> pointer is returned. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> void <B>clear_history</B> <I>()</I> |
| <DD><A NAME="IDX10"></A> |
| Clear the history list by deleting all the entries. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> void <B>stifle_history</B> <I>(int max)</I> |
| <DD><A NAME="IDX11"></A> |
| Stifle the history list, remembering only the last <VAR>max</VAR> entries. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>unstifle_history</B> <I>()</I> |
| <DD><A NAME="IDX12"></A> |
| Stop stifling the history. This returns the previous amount the |
| history was stifled. The value is positive if the history was |
| stifled, negative if it wasn't. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_is_stifled</B> <I>()</I> |
| <DD><A NAME="IDX13"></A> |
| Returns non-zero if the history is stifled, zero if it is not. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC12" HREF="history.html#TOC12">Information About the History List</A></H3> |
| |
| <P> |
| These functions return information about the entire history list or |
| individual list entries. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY ** <B>history_list</B> <I>()</I> |
| <DD><A NAME="IDX14"></A> |
| Return a <CODE>NULL</CODE> terminated array of <CODE>HIST_ENTRY</CODE> which is the |
| current input history. Element 0 of this list is the beginning of time. |
| If there is no history, return <CODE>NULL</CODE>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>where_history</B> <I>()</I> |
| <DD><A NAME="IDX15"></A> |
| Returns the offset of the current history element. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>current_history</B> <I>()</I> |
| <DD><A NAME="IDX16"></A> |
| Return the history entry at the current position, as determined by |
| <CODE>where_history ()</CODE>. If there is no entry there, return a <CODE>NULL</CODE> |
| pointer. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>history_get</B> <I>(int offset)</I> |
| <DD><A NAME="IDX17"></A> |
| Return the history entry at position <VAR>offset</VAR>, starting from |
| <CODE>history_base</CODE>. If there is no entry there, or if <VAR>offset</VAR> |
| is greater than the history length, return a <CODE>NULL</CODE> pointer. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_total_bytes</B> <I>()</I> |
| <DD><A NAME="IDX18"></A> |
| Return the number of bytes that the primary history entries are using. |
| This function returns the sum of the lengths of all the lines in the |
| history. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC13" HREF="history.html#TOC13">Moving Around the History List</A></H3> |
| |
| <P> |
| These functions allow the current index into the history list to be |
| set or changed. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_set_pos</B> <I>(int pos)</I> |
| <DD><A NAME="IDX19"></A> |
| Set the position in the history list to <VAR>pos</VAR>, an absolute index |
| into the list. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>previous_history</B> <I>()</I> |
| <DD><A NAME="IDX20"></A> |
| Back up the current history offset to the previous history entry, and |
| return a pointer to that entry. If there is no previous entry, return |
| a <CODE>NULL</CODE> pointer. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> HIST_ENTRY * <B>next_history</B> <I>()</I> |
| <DD><A NAME="IDX21"></A> |
| Move the current history offset forward to the next history entry, and |
| return the a pointer to that entry. If there is no next entry, return |
| a <CODE>NULL</CODE> pointer. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC14" HREF="history.html#TOC14">Searching the History List</A></H3> |
| <P> |
| <A NAME="IDX22"></A> |
| |
| </P> |
| <P> |
| These functions allow searching of the history list for entries containing |
| a specific string. Searching may be performed both forward and backward |
| from the current history position. The search may be <EM>anchored</EM>, |
| meaning that the string must match at the beginning of the history entry. |
| <A NAME="IDX23"></A> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_search</B> <I>(char *string, int direction)</I> |
| <DD><A NAME="IDX24"></A> |
| Search the history for <VAR>string</VAR>, starting at the current history |
| offset. If <VAR>direction</VAR> < 0, then the search is through previous entries, |
| else through subsequent. If <VAR>string</VAR> is found, then |
| the current history index is set to that history entry, and the value |
| returned is the offset in the line of the entry where |
| <VAR>string</VAR> was found. Otherwise, nothing is changed, and a -1 is |
| returned. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_search_prefix</B> <I>(char *string, int direction)</I> |
| <DD><A NAME="IDX25"></A> |
| Search the history for <VAR>string</VAR>, starting at the current history |
| offset. The search is anchored: matching lines must begin with |
| <VAR>string</VAR>. If <VAR>direction</VAR> < 0, then the search is through previous |
| entries, else through subsequent. If <VAR>string</VAR> is found, then the |
| current history index is set to that entry, and the return value is 0. |
| Otherwise, nothing is changed, and a -1 is returned. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_search_pos</B> <I>(char *string, int direction, int pos)</I> |
| <DD><A NAME="IDX26"></A> |
| Search for <VAR>string</VAR> in the history list, starting at <VAR>pos</VAR>, an |
| absolute index into the list. If <VAR>direction</VAR> is negative, the search |
| proceeds backward from <VAR>pos</VAR>, otherwise forward. Returns the absolute |
| index of the history element where <VAR>string</VAR> was found, or -1 otherwise. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC15" HREF="history.html#TOC15">Managing the History File</A></H3> |
| |
| <P> |
| The History library can read the history from and write it to a file. |
| This section documents the functions for managing a history file. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>read_history</B> <I>(char *filename)</I> |
| <DD><A NAME="IDX27"></A> |
| Add the contents of <VAR>filename</VAR> to the history list, a line at a |
| time. If <VAR>filename</VAR> is <CODE>NULL</CODE>, then read from |
| <TT>`~/.history'</TT>. Returns 0 if successful, or errno if not. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>read_history_range</B> <I>(char *filename, int from, int to)</I> |
| <DD><A NAME="IDX28"></A> |
| Read a range of lines from <VAR>filename</VAR>, adding them to the history list. |
| Start reading at line <VAR>from</VAR> and end at <VAR>to</VAR>. If |
| <VAR>from</VAR> is zero, start at the beginning. If <VAR>to</VAR> is less than |
| <VAR>from</VAR>, then read until the end of the file. If <VAR>filename</VAR> is |
| <CODE>NULL</CODE>, then read from <TT>`~/.history'</TT>. Returns 0 if successful, |
| or <CODE>errno</CODE> if not. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>write_history</B> <I>(char *filename)</I> |
| <DD><A NAME="IDX29"></A> |
| Write the current history to <VAR>filename</VAR>, overwriting <VAR>filename</VAR> |
| if necessary. If <VAR>filename</VAR> is |
| <CODE>NULL</CODE>, then write the history list to <TT>`~/.history'</TT>. Values |
| returned are as in <CODE>read_history ()</CODE>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>append_history</B> <I>(int nelements, char *filename)</I> |
| <DD><A NAME="IDX30"></A> |
| Append the last <VAR>nelements</VAR> of the history list to <VAR>filename</VAR>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_truncate_file</B> <I>(char *filename, int nlines)</I> |
| <DD><A NAME="IDX31"></A> |
| Truncate the history file <VAR>filename</VAR>, leaving only the last |
| <VAR>nlines</VAR> lines. |
| </DL> |
| |
| </P> |
| |
| |
| <H3><A NAME="SEC16" HREF="history.html#TOC16">History Expansion</A></H3> |
| |
| <P> |
| These functions implement <CODE>csh</CODE>-like history expansion. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> int <B>history_expand</B> <I>(char *string, char **output)</I> |
| <DD><A NAME="IDX32"></A> |
| Expand <VAR>string</VAR>, placing the result into <VAR>output</VAR>, a pointer |
| to a string (see section <A HREF="history.html#SEC2">History Expansion</A>). Returns: |
| <DL COMPACT> |
| |
| <DT><CODE>0</CODE> |
| <DD> |
| If no expansions took place (or, if the only change in |
| the text was the de-slashifying of the history expansion |
| character); |
| <DT><CODE>1</CODE> |
| <DD> |
| if expansions did take place; |
| <DT><CODE>-1</CODE> |
| <DD> |
| if there was an error in expansion; |
| <DT><CODE>2</CODE> |
| <DD> |
| if the returned line should only be displayed, but not executed, |
| as with the <CODE>:p</CODE> modifier (see section <A HREF="history.html#SEC5">Modifiers</A>). |
| </DL> |
| |
| <P> |
| If an error ocurred in expansion, then <VAR>output</VAR> contains a descriptive |
| error message. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> char * <B>history_arg_extract</B> <I>(int first, int last, char *string)</I> |
| <DD><A NAME="IDX33"></A> |
| Extract a string segment consisting of the <VAR>first</VAR> through <VAR>last</VAR> |
| arguments present in <VAR>string</VAR>. Arguments are broken up as in Bash. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> char * <B>get_history_event</B> <I>(char *string, int *cindex, int qchar)</I> |
| <DD><A NAME="IDX34"></A> |
| Returns the text of the history event beginning at <VAR>string</VAR> + |
| <VAR>*cindex</VAR>. <VAR>*cindex</VAR> is modified to point to after the event |
| specifier. At function entry, <VAR>cindex</VAR> points to the index into |
| <VAR>string</VAR> where the history event specification begins. <VAR>qchar</VAR> |
| is a character that is allowed to end the event specification in addition |
| to the "normal" terminating characters. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Function:</U> char ** <B>history_tokenize</B> <I>(char *string)</I> |
| <DD><A NAME="IDX35"></A> |
| Return an array of tokens parsed out of <VAR>string</VAR>, much as the |
| shell might. The tokens are split on white space and on the |
| characters <CODE>()<>;&|$</CODE>, and shell quoting conventions are |
| obeyed. |
| </DL> |
| |
| </P> |
| |
| |
| <H2><A NAME="SEC17" HREF="history.html#TOC17">History Variables</A></H2> |
| |
| <P> |
| This section describes the externally visible variables exported by |
| the GNU History Library. |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> int <B>history_base</B> |
| <DD><A NAME="IDX36"></A> |
| The logical offset of the first entry in the history list. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> int <B>history_length</B> |
| <DD><A NAME="IDX37"></A> |
| The number of entries currently stored in the history list. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> int <B>max_input_history</B> |
| <DD><A NAME="IDX38"></A> |
| The maximum number of history entries. This must be changed using |
| <CODE>stifle_history ()</CODE>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> char <B>history_expansion_char</B> |
| <DD><A NAME="IDX39"></A> |
| The character that starts a history event. The default is <SAMP>`!'</SAMP>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> char <B>history_subst_char</B> |
| <DD><A NAME="IDX40"></A> |
| The character that invokes word substitution if found at the start of |
| a line. The default is <SAMP>`^'</SAMP>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> char <B>history_comment_char</B> |
| <DD><A NAME="IDX41"></A> |
| During tokenization, if this character is seen as the first character |
| of a word, then it and all subsequent characters up to a newline are |
| ignored, suppressing history expansion for the remainder of the line. |
| This is disabled by default. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> char * <B>history_no_expand_chars</B> |
| <DD><A NAME="IDX42"></A> |
| The list of characters which inhibit history expansion if found immediately |
| following <VAR>history_expansion_char</VAR>. The default is whitespace and |
| <SAMP>`='</SAMP>. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> char * <B>history_search_delimiter_chars</B> |
| <DD><A NAME="IDX43"></A> |
| The list of additional characters which can delimit a history search |
| string, in addition to whitespace, <SAMP>`:'</SAMP> and <SAMP>`?'</SAMP> in the case of |
| a substring search. The default is empty. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> int <B>history_quotes_inhibit_expansion</B> |
| <DD><A NAME="IDX44"></A> |
| If non-zero, single-quoted words are not scanned for the history expansion |
| character. The default value is 0. |
| </DL> |
| |
| </P> |
| <P> |
| <DL> |
| <DT><U>Variable:</U> Function * <B>history_inhibit_expansion_function</B> |
| <DD><A NAME="IDX45"></A> |
| This should be set to the address of a function that takes two arguments: |
| a <CODE>char *</CODE> (<VAR>string</VAR>) and an integer index into that string (<VAR>i</VAR>). |
| It should return a non-zero value if the history expansion starting at |
| <VAR>string[i]</VAR> should not be performed; zero if the expansion should |
| be done. |
| It is intended for use by applications like Bash that use the history |
| expansion character for additional purposes. |
| By default, this variable is set to NULL. |
| </DL> |
| |
| </P> |
| |
| |
| <H2><A NAME="SEC18" HREF="history.html#TOC18">History Programming Example</A></H2> |
| |
| <P> |
| The following program demonstrates simple use of the GNU History Library. |
| |
| </P> |
| |
| <PRE> |
| main () |
| { |
| char line[1024], *t; |
| int len, done = 0; |
| |
| line[0] = 0; |
| |
| using_history (); |
| while (!done) |
| { |
| printf ("history$ "); |
| fflush (stdout); |
| t = fgets (line, sizeof (line) - 1, stdin); |
| if (t && *t) |
| { |
| len = strlen (t); |
| if (t[len - 1] == '\n') |
| t[len - 1] = '\0'; |
| } |
| |
| if (!t) |
| strcpy (line, "quit"); |
| |
| if (line[0]) |
| { |
| char *expansion; |
| int result; |
| |
| result = history_expand (line, &expansion); |
| if (result) |
| fprintf (stderr, "%s\n", expansion); |
| |
| if (result < 0 || result == 2) |
| { |
| free (expansion); |
| continue; |
| } |
| |
| add_history (expansion); |
| strncpy (line, expansion, sizeof (line) - 1); |
| free (expansion); |
| } |
| |
| if (strcmp (line, "quit") == 0) |
| done = 1; |
| else if (strcmp (line, "save") == 0) |
| write_history ("history_file"); |
| else if (strcmp (line, "read") == 0) |
| read_history ("history_file"); |
| else if (strcmp (line, "list") == 0) |
| { |
| register HIST_ENTRY **the_list; |
| register int i; |
| |
| the_list = history_list (); |
| if (the_list) |
| for (i = 0; the_list[i]; i++) |
| printf ("%d: %s\n", i + history_base, the_list[i]->line); |
| } |
| else if (strncmp (line, "delete", 6) == 0) |
| { |
| int which; |
| if ((sscanf (line + 6, "%d", &which)) == 1) |
| { |
| HIST_ENTRY *entry = remove_history (which); |
| if (!entry) |
| fprintf (stderr, "No such entry %d\n", which); |
| else |
| { |
| free (entry->line); |
| free (entry); |
| } |
| } |
| else |
| { |
| fprintf (stderr, "non-numeric arg given to `delete'\n"); |
| } |
| } |
| } |
| } |
| </PRE> |
| |
| |
| |
| <H1><A NAME="SEC19" HREF="history.html#TOC19">Concept Index</A></H1> |
| <P> |
| Jump to: |
| <A HREF="#a">a</A> |
| - |
| <A HREF="#e">e</A> |
| - |
| <A HREF="#h">h</A> |
| <P> |
| <H2><A NAME="a">a</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX23">anchored search</A> |
| </DIR> |
| <H2><A NAME="e">e</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX2">event designators</A> |
| </DIR> |
| <H2><A NAME="h">h</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX3">history events</A> |
| <LI><A HREF="history.html#IDX1">history expansion</A> |
| <LI><A HREF="history.html#IDX22">History Searching</A> |
| </DIR> |
| |
| </P> |
| |
| |
| <H1><A NAME="SEC20" HREF="history.html#TOC20">Function and Variable Index</A></H1> |
| <P> |
| Jump to: |
| <A HREF="#a">a</A> |
| - |
| <A HREF="#c">c</A> |
| - |
| <A HREF="#g">g</A> |
| - |
| <A HREF="#h">h</A> |
| - |
| <A HREF="#m">m</A> |
| - |
| <A HREF="#n">n</A> |
| - |
| <A HREF="#p">p</A> |
| - |
| <A HREF="#r">r</A> |
| - |
| <A HREF="#s">s</A> |
| - |
| <A HREF="#u">u</A> |
| - |
| <A HREF="#w">w</A> |
| <P> |
| <H2><A NAME="a">a</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX7">add_history</A> |
| <LI><A HREF="history.html#IDX30">append_history</A> |
| </DIR> |
| <H2><A NAME="c">c</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX10">clear_history</A> |
| <LI><A HREF="history.html#IDX16">current_history</A> |
| </DIR> |
| <H2><A NAME="g">g</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX34">get_history_event</A> |
| </DIR> |
| <H2><A NAME="h">h</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX33">history_arg_extract</A> |
| <LI><A HREF="history.html#IDX36">history_base</A> |
| <LI><A HREF="history.html#IDX41">history_comment_char</A> |
| <LI><A HREF="history.html#IDX32">history_expand</A> |
| <LI><A HREF="history.html#IDX39">history_expansion_char</A> |
| <LI><A HREF="history.html#IDX17">history_get</A> |
| <LI><A HREF="history.html#IDX5">history_get_history_state</A> |
| <LI><A HREF="history.html#IDX45">history_inhibit_expansion_function</A> |
| <LI><A HREF="history.html#IDX13">history_is_stifled</A> |
| <LI><A HREF="history.html#IDX37">history_length</A> |
| <LI><A HREF="history.html#IDX14">history_list</A> |
| <LI><A HREF="history.html#IDX42">history_no_expand_chars</A> |
| <LI><A HREF="history.html#IDX44">history_quotes_inhibit_expansion</A> |
| <LI><A HREF="history.html#IDX24">history_search</A> |
| <LI><A HREF="history.html#IDX43">history_search_delimiter_chars</A> |
| <LI><A HREF="history.html#IDX26">history_search_pos</A> |
| <LI><A HREF="history.html#IDX25">history_search_prefix</A> |
| <LI><A HREF="history.html#IDX6">history_set_history_state</A> |
| <LI><A HREF="history.html#IDX19">history_set_pos</A> |
| <LI><A HREF="history.html#IDX40">history_subst_char</A> |
| <LI><A HREF="history.html#IDX35">history_tokenize</A> |
| <LI><A HREF="history.html#IDX18">history_total_bytes</A> |
| <LI><A HREF="history.html#IDX31">history_truncate_file</A> |
| </DIR> |
| <H2><A NAME="m">m</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX38">max_input_history</A> |
| </DIR> |
| <H2><A NAME="n">n</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX21">next_history</A> |
| </DIR> |
| <H2><A NAME="p">p</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX20">previous_history</A> |
| </DIR> |
| <H2><A NAME="r">r</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX27">read_history</A> |
| <LI><A HREF="history.html#IDX28">read_history_range</A> |
| <LI><A HREF="history.html#IDX8">remove_history</A> |
| <LI><A HREF="history.html#IDX9">replace_history_entry</A> |
| </DIR> |
| <H2><A NAME="s">s</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX11">stifle_history</A> |
| </DIR> |
| <H2><A NAME="u">u</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX12">unstifle_history</A> |
| <LI><A HREF="history.html#IDX4">using_history</A> |
| </DIR> |
| <H2><A NAME="w">w</A></H2> |
| <DIR> |
| <LI><A HREF="history.html#IDX15">where_history</A> |
| <LI><A HREF="history.html#IDX29">write_history</A> |
| </DIR> |
| |
| </P> |
| <P><HR><P> |
| This document was generated on 31 December 1998 using the |
| <A HREF="http://wwwinfo.cern.ch/dis/texi2html/">texi2html</A> |
| translator version 1.52.</P> |
| </BODY> |
| </HTML> |