title: Quickest Way to Revert Spaces to TABs in VIM
body: <p>I have always been one to replace TABs in VIM with x amount of spaces (usually 4).
  Four lines I almost always use in my .vimrc config file are:</p>
  
  <pre><code>set tabstop=4 
  
  set shiftwidth=4
  
  set expandtab
  
  syntax on
  </code></pre>
  
  <p>Basically, there are moments when I NEED to use a single TAB (such as Makefiles), and I don't know how else to work around that other than leaving the file, editing my .vimrc, and then reloading the file of interest.</p>
  
  <p>That said, what is the quickest way (from within VIM) to revert it back to using TABS, and then reverting back to my original settings? I'm looking for the least-hassle, least-keystrokes solution.</p>