title: Will provisioning a second time re-run all the shell commands in my script?
body: <p>I'm developing a Vagrant shell script to set up an Ubuntu VM with a whole bunch of things installed. I'm noticing that running <code>sudo apt-get update</code> during provisioning is taking a long time, and so testing that my Vagrant scripts are setting up the VM correctly is really slow.</p>
  
  <p>If I run <code>vagrant provision</code> a second time, is it going to re-run all the shell commands in my script, or will it only re-run newly added setup stuff? I really want to reduce the development time for this script!</p>