1<HTML><HEAD><TITLE>Built-In Commands - history manual page</TITLE></HEAD><BODY> 2<DL> 3<DD><A HREF="history.htm#M2" NAME="L512">NAME</A> 4<DL><DD>history - Manipulate the history list</DL> 5<DD><A HREF="history.htm#M3" NAME="L513">SYNOPSIS</A> 6<DL> 7<DD><B>history </B>?<I>option</I>? ?<I>arg arg ...</I>? 8</DL> 9<DD><A HREF="history.htm#M4" NAME="L514">DESCRIPTION</A> 10<DL> 11</DL> 12<DL> 13<DD><A HREF="history.htm#M5" NAME="L515"><B>history</B></A> 14<DD><A HREF="history.htm#M6" NAME="L516"><B>history add</B><I> command </I>?<B>exec</B>?</A> 15<DD><A HREF="history.htm#M7" NAME="L517"><B>history change</B><I> newValue</I> ?<I>event</I>?</A> 16<DD><A HREF="history.htm#M8" NAME="L518"><B>history clear</B></A> 17<DD><A HREF="history.htm#M9" NAME="L519"><B>history event</B> ?<I>event</I>?</A> 18<DD><A HREF="history.htm#M10" NAME="L520"><B>history info </B>?<I>count</I>?</A> 19<DD><A HREF="history.htm#M11" NAME="L521"><B>history keep </B>?<I>count</I>?</A> 20<DD><A HREF="history.htm#M12" NAME="L522"><B>history nextid</B></A> 21<DD><A HREF="history.htm#M13" NAME="L523"><B>history redo </B>?<I>event</I>?</A> 22</DL> 23<DD><A HREF="history.htm#M14" NAME="L524">HISTORY REVISION</A> 24<DD><A HREF="history.htm#M15" NAME="L525">KEYWORDS</A> 25</DL><HR> 26<H3><A NAME="M2">NAME</A></H3> 27history - Manipulate the history list 28<H3><A NAME="M3">SYNOPSIS</A></H3> 29<B>history </B>?<I>option</I>? ?<I>arg arg ...</I>?<BR> 30<H3><A NAME="M4">DESCRIPTION</A></H3> 31The <B>history</B> command performs one of several operations related to 32recently-executed commands recorded in a history list. Each of 33these recorded commands is referred to as an ``<A HREF="../TkCmd/event.htm">event</A>''. When 34specifying an event to the <B>history</B> command, the following 35forms may be used: 36<P> 37<DL> 38<DT>[1]<DD> 39A number: if positive, it refers to the event with 40that number (all events are numbered starting at 1). If the number 41is negative, it selects an event relative to the current event 42(<B>-1</B> refers to the previous event, <B>-2</B> to the one before that, and 43so on). Event <B>0</B> refers to the current event. 44<P><DT>[2]<DD> 45A string: selects the most recent event that matches the string. 46An event is considered to match the string either if the string is 47the same as the first characters of the event, or if the string 48matches the event in the sense of the <B><A HREF="../TclCmd/string.htm">string match</A></B> command. 49<P></DL> 50<P> 51The <B>history</B> command can take any of the following forms: 52<P> 53<DL> 54<DT><A NAME="M5"><B>history</B></A><DD> 55Same 56as <B>history info</B>, described below. 57<P><DT><A NAME="M6"><B>history add</B><I> command </I>?<B>exec</B>?</A><DD> 58Adds the <I>command</I> argument to the history list as a new event. If 59<B>exec</B> is specified (or abbreviated) then the command is also 60executed and its result is returned. If <B>exec</B> isn't specified 61then an empty string is returned as result. 62<P><DT><A NAME="M7"><B>history change</B><I> newValue</I> ?<I>event</I>?</A><DD> 63Replaces the value recorded for an event with <I>newValue</I>. <I>Event</I> 64specifies the event to replace, and 65defaults to the <I>current</I> event (not event <B>-1</B>). This command 66is intended for use in commands that implement new forms of history 67substitution and wish to replace the current event (which invokes the 68substitution) with the command created through substitution. The return 69value is an empty string. 70<P><DT><A NAME="M8"><B>history clear</B></A><DD> 71Erase the history list. The current keep limit is retained. 72The history event numbers are reset. 73<P><DT><A NAME="M9"><B>history event</B> ?<I>event</I>?</A><DD> 74Returns the value of the event given by <I>event</I>. <I>Event</I> 75defaults to <B>-1</B>. 76<P><DT><A NAME="M10"><B>history info </B>?<I>count</I>?</A><DD> 77Returns a formatted string (intended for humans to read) giving 78the event number and contents for each of the events in the history 79list except the current event. If <I>count</I> is specified 80then only the most recent <I>count</I> events are returned. 81<P><DT><A NAME="M11"><B>history keep </B>?<I>count</I>?</A><DD> 82This command may be used to change the size of the history list to 83<I>count</I> events. Initially, 20 events are retained in the history 84list. If <I>count</I> is not specified, the current keep limit is returned. 85<P><DT><A NAME="M12"><B>history nextid</B></A><DD> 86Returns the number of the next event to be recorded 87in the history list. It is useful for things like printing the 88event number in command-line prompts. 89<P><DT><A NAME="M13"><B>history redo </B>?<I>event</I>?</A><DD> 90Re-executes the command indicated by <I>event</I> and returns its result. 91<I>Event</I> defaults to <B>-1</B>. This command results in history 92revision: see below for details. 93<P></DL> 94<H3><A NAME="M14">HISTORY REVISION</A></H3> 95Pre-8.0 Tcl had a complex history revision mechanism. 96The current mechanism is more limited, and the old 97history operations <B>substitute</B> and <B>words</B> have been removed. 98(As a consolation, the <B>clear</B> operation was added.) 99<P> 100The history option <B>redo</B> results in much simpler ``history revision''. 101When this option is invoked then the most recent event 102is modified to eliminate the history command and replace it with 103the result of the history command. 104If you want to redo an event without modifying history, then use 105the <B><A HREF="../TkCmd/event.htm">event</A></B> operation to retrieve some event, 106and the <B>add</B> operation to add it to history and execute it. 107 108<H3><A NAME="M15">KEYWORDS</A></H3> 109<A href="../Keywords/E.htm#event">event</A>, <A href="../Keywords/H.htm#history">history</A>, <A href="../Keywords/R.htm#record">record</A> 110<HR><PRE> 111<A HREF="../copyright.htm">Copyright</A> © 1993 The Regents of the University of California. 112<A HREF="../copyright.htm">Copyright</A> © 1994-1997 Sun Microsystems, Inc. 113<A HREF="../copyright.htm">Copyright</A> © 1995-1997 Roger E. Critchlow Jr.</PRE> 114</BODY></HTML> 115