title: Shell: Sed -i.bak to rename file by appending current date
body: <p>I have sed statement to replace few contents in my file. It is taking a backup copu with the name <code>file.bak</code> before replacing the content.</p>
  
  <pre><code>sed -i.bak -r "s#^(.*/abc_def_APP/).*(/application1\.war.*)#\1$version1/$version2\2#" /path/file
  </code></pre>
  
  <p>But I want the file to be backed up with current date. something like <code>file.071913</code></p>
  
  <p>How can I get it?</p>