Help for RMATCH:

RMATCH shows all users whose
nick!user@host gecos
matches the given POSIX extended
regular expression.

Instead of a slash, any character that
is not a letter, digit, whitespace or
backslash and does not occur in the pattern
can be used. An i after the pattern means
case insensitive matching.

Syntax: RMATCH /<pattern>/[i]

Example:
    /msg &nick& RMATCH /^m(oo|00)cow/i
    /msg &nick& RMATCH #^[a-z]+!~?[a-z]+@#
    /msg &nick& RMATCH /^[^ ]* [^ ]*$/