title: Matching only first occurence of whitespace using regex
body: <p>I have a .txt file and I'm trying to match the first whitespace in the line (so I can replace it with a tab). I'd like to do carry out the match on each line.</p>
  
  <p>An example of the type of text is: </p>
  
  <pre><code>2014-05-09 12:28:06 Lab bench another
  2014-06-10 01:28:31 Membrane test initiated 
  2014-05-11 12:38:04 Membrane test initiated 
  2014-05-13 14:38:06 Membrane test initiated 
  2014-05-13 12:38:17 Membrane capacitance 
  2014-05-14 16:38:17 Membrane resistance 
  </code></pre>
  
  <p>If I use <code>(?&lt;!n.*)n</code> I can match the first 'n' in each line but if I use <code>(?&lt;!\s.*)\s</code> to match the first whitespace, I only match the first whitespace of the whole text (not on each line).</p>
  
  <p>I'm using EditPad Pro and its multiline search function.</p>