Typical use of $0: 

use Cwd qw( realpath );
use File::Basename qw( dirname basename );

# Look for modules relative to script location
use lib dirname(realpath($0));

sub usage {
    my $prog = basename($0);
    print STDERR "usage: $prog [options] [--] [files]\n";
    exit(1);
}

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In reply to Re: Different meanings of $0 under the same operating system by ikegami
in thread Different meanings of $0 under the same operating system by Jorge_de_Burgos

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