<h1 id="some-additional-bash-tips">Some additional Bash tips</h1>
<h2 id="expansion">Expansion</h2>
<p>As we saw in the last episode <a href="https://hackerpublicradio.org/eps.php?id=1903" title="Some further Bash tips">1903</a> there are seven types of expansion applied to the command line in the following order:</p>
<ul>
<li>Brace expansion (we looked at this subject in episode <a href="https://hackerpublicradio.org/eps.php?id=1884" title="Some more Bash tips">1884</a>)</li>
<li>Tilde expansion (seen in episode <a href="https://hackerpublicradio.org/eps.php?id=1903" title="Some further Bash tips">1903</a>)</li>
<li>Parameter and variable expansion (this was covered in episode <a href="https://hackerpublicradio.org/eps.php?id=1648" title="Bash parameter manipulation">1648</a>)</li>
<li>Command substitution (seen in episode <a href="https://hackerpublicradio.org/eps.php?id=1903" title="Some further Bash tips">1903</a>)</li>
<li>Arithmetic expansion</li>
<li>Word splitting</li>
<li>Pathname expansion</li>
</ul>
<p>There is also another, <em>process substitution</em>, which occurs after <em>arithmetic expansion</em> on systems that can implement it.</p>
<p>We will look at one more of these expansion types in this episode but since there is a lot to cover, we'll continue in a later episode.</p>
<p>I have written out a moderately long set of notes about this subject and these are available here <a href="https://hackerpublicradio.org/eps/hpr1951_full_shownotes.html" class="uri">https://hackerpublicradio.org/eps/hpr1951_full_shownotes.html</a>.</p>
<h3 id="audio-note">Audio Note</h3>
<p>This time, in the spirit of experimentation and as a way of learning Audacity I processed my audio thus:</p>
<ul>
<li><p>Turned the stereo tracks to mono</p></li>
<li><p>Used a Noise Gate plug-in to reduce background noise (after &quot;training&quot; it on some silence)</p></li>
<li><p>Performed a Truncate Silence pass to reduce the length of pauses</p></li>
<li><p>Applied a small amount of amplification</p></li>
</ul>
<p>Let me know if this had any positive or negative effects on the end product.</p>
<h2 id="links">Links</h2>
<ul>
<li>Bash Reference Manual:
<ul>
<li>Arithmetic Expansion: <a href="https://www.gnu.org/software/bash/manual/html_node/Arithmetic-Expansion.html#Arithmetic-Expansion" class="uri">https://www.gnu.org/software/bash/manual/html_node/Arithmetic-Expansion.html#Arithmetic-Expansion</a></li>
<li>Shell Arithmetic: <a href="https://www.gnu.org/software/bash/manual/html_node/Shell-Arithmetic.html#Shell-Arithmetic" class="uri">https://www.gnu.org/software/bash/manual/html_node/Shell-Arithmetic.html#Shell-Arithmetic</a></li>
</ul></li>
<li>HPR episode 1202 &quot;LiTS 025: bc&quot; hosted by <a href="https://hackerpublicradio.org/correspondents/0007.html">Dann Washko</a>: <a href="https://hackerpublicradio.org/eps.php?id=1202" class="uri">https://hackerpublicradio.org/eps.php?id=1202</a></li>
<li>HPR episode 1648 &quot;<em>Bash parameter manipulation</em>&quot;: <a href="https://hackerpublicradio.org/eps.php?id=1648" class="uri">https://hackerpublicradio.org/eps.php?id=1648</a></li>
<li>HPR episode 1843 &quot;<em>Some Bash tips</em>&quot;: <a href="https://hackerpublicradio.org/eps.php?id=1843" class="uri">https://hackerpublicradio.org/eps.php?id=1843</a></li>
<li>HPR episode 1884 &quot;<em>Some more Bash tips</em>&quot;: <a href="https://hackerpublicradio.org/eps.php?id=1884" class="uri">https://hackerpublicradio.org/eps.php?id=1884</a></li>
<li>HPR episode 1903 &quot;<em>Some further Bash tips</em>&quot;: <a href="https://hackerpublicradio.org/eps.php?id=1903" class="uri">https://hackerpublicradio.org/eps.php?id=1903</a></li>
</ul>
