title: Bash to merge 2 consecutive lines in a file
body: <p>I want convert this text on a given file:</p>
  
  <pre><code>87665
  S
  3243423
  S
  334243
  N
  ...
  </code></pre>
  
  <p>to something like this:</p>
  
  <pre><code>87665,S
  3243423,S
  334243,N
  ...
  </code></pre>
  
  <p>I've been reading some <a href="https://stackoverflow.com/questions/14483341/bash-to-merge-lines-in-a-file">similar questions</a>, but it didn't work... is there a way to do this with a single line command in linux? 
  Thanks!</p>