 to install <code>base</code> and <code>core</code>,
  which provide the standard library that all the examples in the book
  are based on, along with <code>utop</code>, which is the interactive
  toplevel that you can use for working through the examples.</p>

<p>Both can be installed as follows:</p>

<pre class="command-line" data-user="rwo" data-host="lama">
  <code class="language-bash">
opam install core core_bench utop
</code></pre>

<p>Other packages will come up in the book, but you can install them