I usually use the below on ActiveState perl. Although I believe it also works on Linux.

use strict;
use warnings;
use English;
use File::Basename qw( dirname );
use File::Spec::Functions qw( rel2abs );

my $script_dir = rel2abs( dirname( $PROGRAM_NAME ) );
print "$script_dir\n";
[download]

You could leave out the "use English" and replace $PROGRAM_NAME with $0

Update:

There is an implicit assumption in the above code, that you are not talking about a CGI script.

You should also look at How do I get the full path to the script executing?

---

data64