lass="headerlink" href="#modifying-move-2-1" title="Permalink to this heading">#</a></h2>
<p>Suppose we want to modify <code class="docutils literal notranslate"><span class="pre">move_2_1</span></code> to get <code class="docutils literal notranslate"><span class="pre">move_3_4</span></code>, a program which would copy the contents of R3 onto the end of R4 (and empty R4) in the process. Here is a way to do this which shows off some command-line tools that are part of the working environment that comes with