title: Appending 0's to a file in unix/bash if the line is less than a fixed length
body: <p>I am looking for a way in which to append 0's to the end of multiple lines in a file if they are less than 66 characters in length so that the total line length equals 66.</p>
  
  <p>Here's an example of the file format (... denotes preceding 56 characters):</p>
  
  <pre><code>$cat file1
  ...1234567891
  ...123456
  ...
  ...12345678
  </code></pre>
  
  <p>Ideal format:</p>
  
  <pre><code>...1234567891
  ...1234560000
  ...0000000000
  ...1234567800
  </code></pre>