perl -MPOSIX -e'print `ps --no-header -p @{[getpid()]} -o sz`'


Update:

BrowserUk says Re Re: Total Memory Size Used up by a Perl Script Why POSIX/getpid() and not $$?

Because I'm an idiot. Post an insulting comment so I can upvote you!

perl -e'print `ps --no-header -p$$ -osz`'