title: How to add a progress bar to a shell script?
body: <p>When scripting in bash or any other shell in *NIX, while running a command that will take more than a few seconds, a progress bar is needed.</p>
  
  <p>For example, copying a big file, opening a big tar file.</p>
  
  <p>What ways do you recommend to add progress bars to shell scripts?</p>