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17<title>Debugging with GDB: Guile Commands</title>
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64<a name="Guile-Commands"></a>
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66<p>
67Next: <a href="Guile-API.html#Guile-API" accesskey="n" rel="next">Guile API</a>, Previous: <a href="Guile-Introduction.html#Guile-Introduction" accesskey="p" rel="previous">Guile Introduction</a>, Up: <a href="Guile.html#Guile" accesskey="u" rel="up">Guile</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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70<a name="Guile-Commands-1"></a>
71<h4 class="subsection">23.3.2 Guile Commands</h4>
72<a name="index-guile-commands"></a>
73<a name="index-commands-to-access-guile"></a>
74
75<p><small>GDB</small> provides two commands for accessing the Guile interpreter:
76</p>
77<dl compact="compact">
78<dd><a name="index-guile_002drepl"></a>
79<a name="index-gr"></a>
80</dd>
81<dt><code>guile-repl</code></dt>
82<dt><code>gr</code></dt>
83<dd><p>The <code>guile-repl</code> command can be used to start an interactive
84Guile prompt or <em>repl</em>.  To return to <small>GDB</small>,
85type <kbd>,q</kbd> or the <code>EOF</code> character (e.g., <kbd>Ctrl-D</kbd> on
86an empty prompt).  These commands do not take any arguments.
87</p>
88<a name="index-guile"></a>
89<a name="index-gu"></a>
90</dd>
91<dt><code>guile <span class="roman">[</span><var>scheme-expression</var><span class="roman">]</span></code></dt>
92<dt><code>gu <span class="roman">[</span><var>scheme-expression</var><span class="roman">]</span></code></dt>
93<dd><p>The <code>guile</code> command can be used to evaluate a Scheme expression.
94</p>
95<p>If given an argument, <small>GDB</small> will pass the argument to the Guile
96interpreter for evaluation.
97</p>
98<div class="smallexample">
99<pre class="smallexample">(gdb) guile (display (+ 20 3)) (newline)
10023
101</pre></div>
102
103<p>The result of the Scheme expression is displayed using normal Guile rules.
104</p>
105<div class="smallexample">
106<pre class="smallexample">(gdb) guile (+ 20 3)
10723
108</pre></div>
109
110<p>If you do not provide an argument to <code>guile</code>, it will act as a
111multi-line command, like <code>define</code>.  In this case, the Guile
112script is made up of subsequent command lines, given after the
113<code>guile</code> command.  This command list is terminated using a line
114containing <code>end</code>.  For example:
115</p>
116<div class="smallexample">
117<pre class="smallexample">(gdb) guile
118&gt;(display 23)
119&gt;(newline)
120&gt;end
12123
122</pre></div>
123</dd>
124</dl>
125
126<p>It is also possible to execute a Guile script from the <small>GDB</small>
127interpreter:
128</p>
129<dl compact="compact">
130<dt><code>source <samp>script-name</samp></code></dt>
131<dd><p>The script name must end with &lsquo;<samp>.scm</samp>&rsquo; and <small>GDB</small> must be configured
132to recognize the script language based on filename extension using
133the <code>script-extension</code> setting.  See <a href="Extending-GDB.html#Extending-GDB">Extending GDB</a>.
134</p>
135</dd>
136<dt><code>guile (load &quot;script-name&quot;)</code></dt>
137<dd><p>This method uses the <code>load</code> Guile function.
138It takes a string argument that is the name of the script to load.
139See the Guile documentation for a description of this function.
140(see <a href="http://www.gnu.org/software/guile/manual/html_node/Loading.html#Loading">Loading</a> in <cite>GNU Guile Reference Manual</cite>).
141</p></dd>
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