Subject: Re: How to show the diff command when there is a difference when comparing two files?

From: Paul Eggert <[email-masked]>
Date: Sat, 29 Mar 2014 22:22:40 -0700

> I'm wondering if I just compare two files, it is
> possible to print the diff command if there is a difference between
> the two files?

Not in diff itself, but it's easy to do from a shell script.  E.g.,

command="diff a b"
$command >output || {
   echo "$command"
   cat output
}