title: How can I run two isolated installations of Homebrew?
body: <p>I want to install and run two versions of Homebrew simultaneously on an Apple Silicon Mac: an ARM64 version, and an Intel version running under Rosetta 2.</p>
  <p>I <a href="https://stackoverflow.com/questions/64882584/how-to-run-the-homebrew-installer-under-rosetta-2-on-m1-macbook/64883440#64883440">know</a> I can prepend any brew command with <code>arch --x86_64</code> to emulate Intel for that command, but this can lead to conflicts for formulas whose dependencies you already have built for ARM64. For example:</p>
  <pre><code>Error: gnupg dependencies not built for the x86_64 CPU architecture:
    pkg-config was built for arm64
    gettext was built for arm64
    readline was built for arm64
    openssl@1.1 was built for arm64
  </code></pre>
  <p>How can I install and run two separate, isolated versions of Homebrew (one for native ARM64 and one for emulated Intel), keeping each of their installed formulae and dependencies separate?</p>