You're after the variables $0 and $$:

$0

Contains the name of the program being executed. On some operating systems assigning to "$0" modifies the argument area that the ps program sees. This is more useful as a way of indicating the current program state than it is for hiding the program you're running. (Mnemonic: same as sh and ksh.)

$$

The process number of the Perl running this script. You should consider this variable read-only, although it will be altered across fork() calls. (Mnemonic: same as shells.)

See. your local perlvar for further details.
HTH

_________
broquaint