All supported versions of Debian and Ubuntu include a version of Ruby you can use with Arvados.
<notextile>
-<pre><code># <span class="userinput">apt-get --no-install-recommends install ruby ruby-dev</span></code></pre>
+<pre><code># <span class="userinput">apt --no-install-recommends install ruby ruby-dev</span></code></pre>
</notextile>