$ mkdir diamondtest
$ cd diamondtest
$ touch 'rm * | ' a b c d  # create 5 files
$ ls  # now you see it
$ perl -pe 1 *
$ ls  # now you don't -- no files

##</code><code>##

while (defined($_ = <ARGV>)) { ... }

##</code><code>##

# strip blank lines
perl -pe 's=^\s*$=='

##</code><code>##

perl -Tpe 's=^\s*$=='