title: String difference in Bash
body: <p>I'm trying to find a way to determine the difference between two strings in my script. I could easily do this with diff or comm, but I'm not dealing with files and I'd prefer not to output them to files, do the compare and read it back.</p>
  
  <p>I see that comm, diff, cmp all allow to pass either two files OR a file and standard input - I guess that's good if I don't want to output two files...but it's still kinda sucks.</p>
  
  <p>Been digging around thinking I can use grep or regular expressions - but I guess not.</p>