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<span id="Shell-Conventions"></span><div class="header">
<p>
Next: <a href="Repository-Conventions.html" accesskey="n" rel="next">Repository Conventions</a>, Up: <a href="Conventions.html" accesskey="u" rel="up">Conventions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
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<hr>
<span id="Shell-Conventions-1"></span><h4 class="subsection">3.1.1 Shell Conventions</h4>
<p>Shell is central to Carbs Linux projects. Most of the tools and packages are
written in POSIX sh.
</p>
<dl compact="compact">
<dt>[<span id="g_t1010"></span>1010]</dt>
<dd><p>Use 4 spaces for indentation, don’t use tabs.
</p></dd>
<dt>[<span id="g_t1020"></span>1020]</dt>
<dd><p>Make sure you don’t use bash-specific code.
</p></dd>
<dt>[<span id="g_t1030"></span>1030]</dt>
<dd><p>Make sure you lint your code with ‘<samp>shellcheck</samp>’ and if
you are new to POSIX sh, use ‘<samp>checkbashisms</samp>’.
</p></dd>
<dt>[<span id="g_t1040"></span>1040]</dt>
<dd><p>Don’t spawn new processes if you don’t absolutely need
to, especially during string manipulation.
</p><dl compact="compact">
<dt>[<span id="g_t1041"></span>1041]</dt>
<dd><p>Never use a program for text manupilation that isn’t
defined in the POSIX standard. This includes ‘<samp>gawk</samp>’ and ‘<samp>perl</samp>’.
</p></dd>
<dt>[<span id="g_t1042"></span>1042]</dt>
<dd><p>Instead of <code>$(basename $file)</code>, use <code>${file##*}</code>.
</p></dd>
<dt>[<span id="g_t1043"></span>1043]</dt>
<dd><p>Instead of <code>$(dirname $file)</code>, use <code>${file%/*}</code>.
</p></dd>
</dl>
<div class="example">
<pre class="example"># This is the same thing as basename /path/to/test.asc .asc
$ file=/path/to/test.asc file=${file##*/} file=${file%.asc}
$ echo $file
test
</pre></div>
</dd>
<dt>[<span id="g_t1050"></span>1050]</dt>
<dd><p>Instead of backticks, use <code>$(..)</code>.
</p></dd>
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