Three arguements form? Would you mind giving me a (simple) example?

I must say i'm tempted to say: no! For I'm not here (and nobody is) to replace the best tool to answer this kind of questions, that is Perl's excellent documentation.

However...

open my $fh, '|-', "whatever" or die $!;
# or
open my $fh, '|-', "whatever", @more_args or die $!;
[download]