title: Command to trim the first and last character of a line in a text file
body: <p>I am looking for I one liner hopefully, that can trim the first and last character of a line, on multiple lines e.g. test.txt</p>
  
  <p>Before:</p>
  
  <pre><code>xyyyyyyyyyyyyyyyyyyyx
  pyyyyyyyyyyyyyyyyyyyz
  </code></pre>
  
  <p>After:</p>
  
  <pre><code>yyyyyyyyyyyyyyyyyyy
  yyyyyyyyyyyyyyyyyyy
  </code></pre>