title: What is the definitive way to install/upgrade/set the default version of ZSH?
body: <p>OSX Mountain Lion ships with ZSH 4.3.1 in /bin/zsh. After downloading, <code>./configure, make, make check,</code> and <code>make install</code>-ing version 5.0.0, </p>
  
  <p><code>which zsh</code> still returns <code>/bin/zsh/</code> </p>
  
  <p>and <code>zsh --version</code> still returns <code>zsh 4.3.11 (i386-apple-darwin12.0)</code></p>
  
  <p><strong>Items of note to help answerers:</strong><br>
  I had no errors running the install commands.   </p>
  
  <p>In <code>/usr/local/bin</code>, I have these 3 files:<br>
  <code>-rwxr-xr-x   2 kevinsuttle  admin   622K Aug 20 00:59 zsh</code><br>
  <code>-rwxr-xr-x   2 kevinsuttle  admin   622K Aug 20 00:59 zsh-5.0.0</code><br>
  <code>-rwxr-xr-x   1 kevinsuttle  admin   622K Aug 20 00:50 zsh.old</code>  </p>
  
  <p><strong>My <code>$PATH</code></strong><br>
  <code>$ echo $PATH</code><br>
  <code>/Users/kevinsuttle/.rbenv/shims:/Users/kevinsuttle/.rbenv/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin</code></p>
  
  <p><strong>Questions I need answered</strong>:<br>
  1. What is the cleanest way to install ZSH? (From git, homebrew, curl-ing source?)<br>
  2. Does it matter where you run the install commands?<br>
  3. How do I upgrade or override the version of ZSH that ships with Mountain Lion?<br>
  4. Is this why people end up using <a href="https://github.com/robbyrussell/oh-my-zsh" rel="noreferrer">oh-my-zsh</a>?</p>