Hunting Perl Bots with Grep

I think one of my servers may have a perl bot on it somewhere; one of my WP sites was hacked.

I found this great resource explaining how to use Grep to look for perl bots:

http://pentestlab.org/hunting-malicious-perl-irc-bots/#!prettyPhoto

I'd like to try this approach but the commands don't work on my Centos box:

[root@server ~]# grep -RPn “(system|shell|tcp) *(” /var/www
-bash: syntax error near unexpected token `('

Are there any Linux wizs here who can spot the error? Diagnosing it is beyond my limited skills.