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<a name="Output-_0028Object_0029-File"></a>
<h3 class="section">1.6 Output (Object) File</h3>

<a name="index-object-file"></a>
<a name="index-output-file"></a>
<a name="index-a_002eout"></a>
<a name="index-_002eo"></a>
<p>Every time you run <code>as</code> it produces an output file, which is
your assembly language program translated into numbers.  This file
is the object file.  Its default name is
<code>a.out</code>.
You can give it another name by using the <samp>-o</samp> option.  Conventionally,
object file names end with <samp>.o</samp>.  The default name is used for historical
reasons: older assemblers were capable of assembling self-contained programs
directly into a runnable program.  (For some formats, this isn&rsquo;t currently
possible, but it can be done for the <code>a.out</code> format.)
</p>
<a name="index-linker"></a>
<a name="index-ld"></a>
<p>The object file is meant for input to the linker <code>ld</code>.  It contains
assembled program code, information to help <code>ld</code> integrate
the assembled program into a runnable file, and (optionally) symbolic
information for the debugger.
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