in reply to Re^2: Hash: Removing a specific value from a multi-valued key
in thread Hash: Removing a specific value from a multi-valued key

Bloodnok is referring to the Perl built-in grep function, which should be available to you, not the unix grep utility. Yes, it is confusing.
  • Comment on Re^3: Hash: Removing a specific value from a multi-valued key

In Section Seekers of Perl Wisdom