in reply to backreference followed by literal in regex substitution

/some search criteria/$1$2$3\[2010\]$4$5/g'

-- Randal L. Schwartz, Perl hacker

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

In Section Seekers of Perl Wisdom