de class="code">plz build --shell</code> will prepare a target for
    building and open up a shell into the directory, where you can look around
    and try running commands by hand.
  </p>

  <p>
    Some aspects of this environment are different to normal - for example rules
    are given a small, deterministic set of environment variables. They
    shouldn't need to read anything outside this directory or not described by
    those variables. See the
    <a class="copy-link" href="#pass-env">Passing env