title: how to remove lines from file that don't match regex?
body: <p>I have a big file that looks like this:</p>
  
  <pre><code>7f0c41d6-f9c6-47aa-a034-d40bc629c973.csv
  159890
  159891
  24faaed6-62ee-4175-8430-5d73b09911c8.csv
  159907
  5bad221f-25ef-44fa-9086-fd152e697928.csv
  642e4ac3-3d46-4b4c-b5c8-aa2fa54d0b04.csv
  d0e145a5-ceb8-4d4b-ae47-11e0c9a6548d.csv
  159929
  ba678cbd-af57-493b-a69e-e7504b4bc328.csv
  7750840f-9bf9-4a68-9f25-a2ba0968d481.csv
  159955
  159959
  </code></pre>
  
  <p>And I'm only interesting in <code>*.csv</code>  files, can someone point me how to remove files that do not end with <code>.csv</code>.</p>
  
  <p>Thank you.</p>