How can you get basename of a Perl script on any OS using regular expression?

$me = $0;

if ( $^O eq 'MSWin32' )
{
         $me=~s{.*\\}{};
         print "Usage :  $me <file>!\n"
}
else
{
         $me=~s{.*/}{};
         print "Usage :  $me <file>!\n"
}

Or

my $command = $0;
$command =~ s#^.*/##;

Or

( my $me = $0 ) =~ s{.*(\\|/)}{};