The makefile contains the actual commands for the demo, which are nothing simpler than one of these:

$ copyright-injection.pl  . check
$ copyright-injection.pl  . add
$ copyright-injection.pl  . remove
$ copyright-injection.pl  --help


DEMO
$ make remove            # deletes copyright notices from all pl and pm files under lib/ and script/
$ make grep              # verify that copyright notices have been removed
$ make add               # add copyright notices back again
$ make grep              # verify they have been added