How do I get the full path to a Perl script that is executing? – Right way.

use Cwd qw(abs_path cwd);
my $cwd = cwd();
my $abs_path = abs_path();
my $FILE = __FILE__;
print "1. $cwd $abs_path $FILE\n";



use File::Basename;
my $dirname = dirname(__FILE__);
print "2. $dirname\n";

use File::Spec;
my $relabs = File::Spec->rel2abs( __FILE__ );
print "3. $relabs\n";

my $good = `readlink -f $0`;
print "4. $good\n";

so as it:

user@it.sysnet.by [/var]# pwd
/var
user@it.sysnet.by [/var]# ../home/user/backups/run.pl
4. /home/user/backups/run.pl
user@it.sysnet.by [/var]# 

use File::Basename;
my $place = `readlink -f $0`;
chomp($place);
$place = dirname($place);
print "$place\n";