C:\>more temp.pl
#!/usr/bin/perl --
use strict;
use warnings;

my ($package, $filename, $line) = eval { caller };

print "\$0 $0\n";
print "filename $filename\n";
print "__FILE__ ", __FILE__,"\n";

__END__


C:\>perl temp.pl
$0 temp.pl
filename temp.pl
__FILE__ temp.pl

C:\>