1<html lang="en"> 2<head> 3<title>Aliases - Debugging with GDB</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Debugging with GDB"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="Extending-GDB.html#Extending-GDB" title="Extending GDB"> 9<link rel="prev" href="Python.html#Python" title="Python"> 10<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 11<!-- 12Copyright (C) 1988-2013 Free Software Foundation, Inc. 13 14Permission is granted to copy, distribute and/or modify this document 15under the terms of the GNU Free Documentation License, Version 1.3 or 16any later version published by the Free Software Foundation; with the 17Invariant Sections being ``Free Software'' and ``Free Software Needs 18Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' 19and with the Back-Cover Texts as in (a) below. 20 21(a) The FSF's Back-Cover Text is: ``You are free to copy and modify 22this GNU Manual. 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For example ‘<samp><span class="samp">s</span></samp>’ is an alias 57of the ‘<samp><span class="samp">step</span></samp>’ command even though it is otherwise an ambiguous 58abbreviation of other commands like ‘<samp><span class="samp">set</span></samp>’ and ‘<samp><span class="samp">show</span></samp>’. 59 60 <p>Aliases are also used to provide shortened or more common versions 61of multi-word commands. For example, <span class="sc">gdb</span> provides the 62‘<samp><span class="samp">tty</span></samp>’ alias of the ‘<samp><span class="samp">set inferior-tty</span></samp>’ command. 63 64 <p>You can define a new alias with the ‘<samp><span class="samp">alias</span></samp>’ command. 65 66 67<a name="index-alias-2211"></a> 68<dl><dt><code>alias [-a] [--] </code><var>ALIAS</var><code> = </code><var>COMMAND</var><dd> 69</dl> 70 71 <p><var>ALIAS</var> specifies the name of the new alias. 72Each word of <var>ALIAS</var> must consist of letters, numbers, dashes and 73underscores. 74 75 <p><var>COMMAND</var> specifies the name of an existing command 76that is being aliased. 77 78 <p>The ‘<samp><span class="samp">-a</span></samp>’ option specifies that the new alias is an abbreviation 79of the command. Abbreviations are not shown in command 80lists displayed by the ‘<samp><span class="samp">help</span></samp>’ command. 81 82 <p>The ‘<samp><span class="samp">--</span></samp>’ option specifies the end of options, 83and is useful when <var>ALIAS</var> begins with a dash. 84 85 <p>Here is a simple example showing how to make an abbreviation 86of a command so that there is less to type. 87Suppose you were tired of typing ‘<samp><span class="samp">disas</span></samp>’, the current 88shortest unambiguous abbreviation of the ‘<samp><span class="samp">disassemble</span></samp>’ command 89and you wanted an even shorter version named ‘<samp><span class="samp">di</span></samp>’. 90The following will accomplish this. 91 92<pre class="smallexample"> (gdb) alias -a di = disas 93</pre> 94 <p>Note that aliases are different from user-defined commands. 95With a user-defined command, you also need to write documentation 96for it with the ‘<samp><span class="samp">document</span></samp>’ command. 97An alias automatically picks up the documentation of the existing command. 98 99 <p>Here is an example where we make ‘<samp><span class="samp">elms</span></samp>’ an abbreviation of 100‘<samp><span class="samp">elements</span></samp>’ in the ‘<samp><span class="samp">set print elements</span></samp>’ command. 101This is to show that you can make an abbreviation of any part 102of a command. 103 104<pre class="smallexample"> (gdb) alias -a set print elms = set print elements 105 (gdb) alias -a show print elms = show print elements 106 (gdb) set p elms 20 107 (gdb) show p elms 108 Limit on string chars or array elements to print is 200. 109</pre> 110 <p>Note that if you are defining an alias of a ‘<samp><span class="samp">set</span></samp>’ command, 111and you want to have an alias for the corresponding ‘<samp><span class="samp">show</span></samp>’ 112command, then you need to define the latter separately. 113 114 <p>Unambiguously abbreviated commands are allowed in <var>COMMAND</var> and 115<var>ALIAS</var>, just as they are normally. 116 117<pre class="smallexample"> (gdb) alias -a set pr elms = set p ele 118</pre> 119 <p>Finally, here is an example showing the creation of a one word 120alias for a more complex command. 121This creates alias ‘<samp><span class="samp">spe</span></samp>’ of the command ‘<samp><span class="samp">set print elements</span></samp>’. 122 123<pre class="smallexample"> (gdb) alias spe = set print elements 124 (gdb) spe 20 125</pre> 126 </body></html> 127 128