The $0 variable can be used to get the name of the Perl script being invoked. For example, let's say you have a Perl script named foo.pl. Here is how you would show that foo.pl is the name of the script.

#!/usr/bin/perl
use strict;
use warnings;
print "Script name = $0 \n";

Or, more commonly, scriptname is stored in a constant variable.

#!/usr/bin/perl
use strict;
use warnings;
my $scriptname = $0;
print "Script name = $scriptname \n";

Which should return the following.

Script name = foo.pl