title: string (file1.txt) search from file2.txt
body: <p><code>file1.txt</code> contains usernames, i.e.  </p>
  
  <pre><code>tony  
  peter  
  john  
  ...
  </code></pre>
  
  <p><code>file2.txt</code> contains user details, just one line for each user details, i.e.  </p>
  
  <pre><code>alice 20160102 1101 abc  
  john 20120212 1110 zjc9  
  mary 20140405 0100 few3  
  peter 20140405 0001 io90  
  tango 19090114 0011 n4-8  
  tony 20150405 1001 ewdf  
  zoe 20000211 0111 jn09  
  ...
  </code></pre>
  
  <p>I want to get a shortlist of user details from <code>file2.txt</code> by <code>file1.txt</code> user provided, i.e.  </p>
  
  <pre><code>john 20120212 1110 zjc9  
  peter 20140405 0001 io90  
  tony 20150405 1001 ewdf  
  </code></pre>
  
  <p>How to use python to do this?</p>