title: Add text at the end of each line
body: <p>I'm on Linux command line and I have file with</p>
  
  <pre><code>127.0.0.1
  128.0.0.0
  121.121.33.111
  </code></pre>
  
  <p>I want</p>
  
  <pre><code>127.0.0.1:80
  128.0.0.0:80
  121.121.33.111:80
  </code></pre>
  
  <p>I remember my colleagues were using sed for that, but after reading sed manual still not clear how to do it on command line?</p>