title: Find and replace first occurrence of a space
body: <p>Given a line of text with two words, such as:</p>
  
  <p><strong>hi hello</strong></p>
  
  <p>How can I replace the first occurrence of a space with a comma, giving desired result:</p>
  
  <p><strong>hi, hello</strong></p>
  
  <p>Sublime text regex <code>^([^\s]*)(\s)</code> gives:</p>
  
  <p><code>hi</code>hello</p>
  
  <p>Where the gray represents the selected area (notice it's also including the word <code>hi</code>, when it should only include the first space for replacing), which if I ran find replace on, would give:</p>
  
  <p><strong>, hello</strong></p>