title: How do I replace first space with comma in UNIX
body: <p>My Question is, I have 2 columns. The text in the secound column has comma seperated values. I want the 2 columns to be deisplayed as comma seperated and the comma seperated text in 2nd column should remain as it is.</p>
  
  <p>E.g: A,B being the name of the columns:</p>
  
  <pre><code>A   B
  123 Hi There
  234 Hello there
  </code></pre>
  
  <p>I want the output as</p>
  
  <pre><code>A,B
  123,Hi There
  234,Hellothere
  </code></pre>
  
  <p>Can someone please help me?</p>