title: Search and replace values in text file with C#
body: <p>I have a text file with a certain format. First comes an identifier followed by three spaces and a colon. Then comes the value for this identifier.</p>
  
  <pre><code>ID1   :Value1  
  ID2   :Value2  
  ID3   :Value3
  </code></pre>
  
  <p>What I need to do is searching e.g. for <code>ID2   :</code> and replace <code>Value2</code> with a new value <code>NewValue2</code>. What would be a way to do this? The files I need to parse won't get very large. The largest will be around 150 lines.</p>