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<a name="Invoking-GDB"></a>
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<p>
Next: <a href="Quitting-GDB.html#Quitting-GDB" accesskey="n" rel="next">Quitting GDB</a>, Up: <a href="Invocation.html#Invocation" accesskey="u" rel="up">Invocation</a> [<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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<a name="Invoking-GDB-1"></a>
<h3 class="section">2.1 Invoking <small>GDB</small></h3>
<p>Invoke <small>GDB</small> by running the program <code>gdb</code>. Once started,
<small>GDB</small> reads commands from the terminal until you tell it to exit.
</p>
<p>You can also run <code>gdb</code> with a variety of arguments and options,
to specify more of your debugging environment at the outset.
</p>
<p>The command-line options described here are designed
to cover a variety of situations; in some environments, some of these
options may effectively be unavailable.
</p>
<p>The most usual way to start <small>GDB</small> is with one argument,
specifying an executable program:
</p>
<div class="smallexample">
<pre class="smallexample">gdb <var>program</var>
</pre></div>
<p>You can also start with both an executable program and a core file
specified:
</p>
<div class="smallexample">
<pre class="smallexample">gdb <var>program</var> <var>core</var>
</pre></div>
<p>You can, instead, specify a process ID as a second argument or use option
<code>-p</code>, if you want to debug a running process:
</p>
<div class="smallexample">
<pre class="smallexample">gdb <var>program</var> 1234
gdb -p 1234
</pre></div>
<p>would attach <small>GDB</small> to process <code>1234</code>. With option <samp>-p</samp> you
can omit the <var>program</var> filename.
</p>
<p>Taking advantage of the second command-line argument requires a fairly
complete operating system; when you use <small>GDB</small> as a remote
debugger attached to a bare board, there may not be any notion of
“process”, and there is often no way to get a core dump. <small>GDB</small>
will warn you if it is unable to attach or to read core dumps.
</p>
<p>You can optionally have <code>gdb</code> pass any arguments after the
executable file to the inferior using <code>--args</code>. This option stops
option processing.
</p><div class="smallexample">
<pre class="smallexample">gdb --args gcc -O2 -c foo.c
</pre></div>
<p>This will cause <code>gdb</code> to debug <code>gcc</code>, and to set
<code>gcc</code>’s command-line arguments (see <a href="Arguments.html#Arguments">Arguments</a>) to ‘<samp>-O2 -c foo.c</samp>’.
</p>
<p>You can run <code>gdb</code> without printing the front material, which describes
<small>GDB</small>’s non-warranty, by specifying <code>--silent</code>
(or <code>-q</code>/<code>--quiet</code>):
</p>
<div class="smallexample">
<pre class="smallexample">gdb --silent
</pre></div>
<p>You can further control how <small>GDB</small> starts up by using command-line
options. <small>GDB</small> itself can remind you of the options available.
</p>
<p>Type
</p>
<div class="smallexample">
<pre class="smallexample">gdb -help
</pre></div>
<p>to display all available options and briefly describe their use
(‘<samp>gdb -h</samp>’ is a shorter equivalent).
</p>
<p>All options and command line arguments you give are processed
in sequential order. The order makes a difference when the
‘<samp>-x</samp>’ option is used.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">• <a href="File-Options.html#File-Options" accesskey="1">File Options</a>:</td><td> </td><td align="left" valign="top">Choosing files
</td></tr>
<tr><td align="left" valign="top">• <a href="Mode-Options.html#Mode-Options" accesskey="2">Mode Options</a>:</td><td> </td><td align="left" valign="top">Choosing modes
</td></tr>
<tr><td align="left" valign="top">• <a href="Startup.html#Startup" accesskey="3">Startup</a>:</td><td> </td><td align="left" valign="top">What <small>GDB</small> does during startup
</td></tr>
</table>
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<p>
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