[jcynix]

Sure, but my example was just that and I actually use /identical$/ as the pattern. Sorry for the typo.

And I use this "historic" one liner only when I know about the contents of both directories. As soon as I need a "safer" solution I use a Perl script and pattern matching, as I said.

[poke646]

In this case the Perl one-liner would be conceptually identical, the same length, but more performant (no calling out to rm):

   diff -rs a/ b/ | perl -ane '/identical$/ && unlink $F[3]'