title: Customising word separators in vi
body: <p>vi treats dash <code>-</code> and space <code>&nbsp;</code> as word separators for commands such as <code>dw</code> and <code>cw</code>.</p>
  
  <p>Is there a way to add underscore <code>_</code> as well?</p>
  
  <p>I quite often want to change part of a variable name containing underscores, such as changing <code>src_branch</code> to <code>dest_branch</code>. I end up counting characters and using <code>s</code> (like <code>3sdest</code>), but it would be much easier to use <code>cw</code> (like <code>cwdest</code>).</p>