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<h4 class="subsection">25.3.12 Argp User Customization</h4>

<p><a name="index-ARGP_005fHELP_005fFMT-environment-variable-3096"></a>The formatting of argp &lsquo;<samp><span class="samp">--help</span></samp>&rsquo; output may be controlled to some
extent by a program's users, by setting the <code>ARGP_HELP_FMT</code>
environment variable to a comma-separated list of tokens.  Whitespace is
ignored:

     <dl>
<dt>&lsquo;<samp><span class="samp">dup-args</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">no-dup-args</span></samp>&rsquo;<dd>These turn <dfn>duplicate-argument-mode</dfn> on or off.  In duplicate
argument mode, if an option that accepts an argument has multiple names,
the argument is shown for each name.  Otherwise, it is only shown for the
first long option.  A note is subsequently printed so the user knows that
it applies to other names as well.  The default is &lsquo;<samp><span class="samp">no-dup-args</span></samp>&rsquo;,
which is less consistent, but prettier.

     <br><dt>&lsquo;<samp><span class="samp">dup-args-note</span></samp>&rsquo;<br><dt>&lsquo;<samp><span class="samp">no-dup-args-note</span></samp>&rsquo;<dd>These will enable or disable the note informing the user of suppressed
option argument duplication.  The default is &lsquo;<samp><span class="samp">dup-args-note</span></samp>&rsquo;.

     <br><dt>&lsquo;<samp><span class="samp">short-opt-col=</span><var>n</var></samp>&rsquo;<dd>This prints the first short option in column <var>n</var>.  The default is 2.

     <br><dt>&lsquo;<samp><span class="samp">long-opt-col=</span><var>n</var></samp>&rsquo;<dd>This prints the first long option in column <var>n</var>.  The default is 6.

     <br><dt>&lsquo;<samp><span class="samp">doc-opt-col=</span><var>n</var></samp>&rsquo;<dd>This prints `documentation options' (see <a href="Argp-Option-Flags.html#Argp-Option-Flags">Argp Option Flags</a>) in
column <var>n</var>.  The default is 2.

     <br><dt>&lsquo;<samp><span class="samp">opt-doc-col=</span><var>n</var></samp>&rsquo;<dd>This prints the documentation for options starting in column
<var>n</var>.  The default is 29.

     <br><dt>&lsquo;<samp><span class="samp">header-col=</span><var>n</var></samp>&rsquo;<dd>This will indent the group headers that document groups of options to
column <var>n</var>.  The default is 1.

     <br><dt>&lsquo;<samp><span class="samp">usage-indent=</span><var>n</var></samp>&rsquo;<dd>This will indent continuation lines in &lsquo;<samp><span class="samp">Usage:</span></samp>&rsquo; messages to column
<var>n</var>.  The default is 12.

     <br><dt>&lsquo;<samp><span class="samp">rmargin=</span><var>n</var></samp>&rsquo;<dd>This will word wrap help output at or before column <var>n</var>.  The default
is 79. 
</dl>

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