For information about Perl's
grep command, use
perldoc -f grep.
To reverse the condition, negate the condition:
grep { !( expression ) } LIST (Using a block is easier in many cases, and read
perlop to find out when you can leave out the parens).
To reverse grep's output, use
reverse:
reverse grep BLOCK LIST or
reverse grep EXPR, LIST
Lbh ebgngrq guvf grkg naq abj lbh pna ernq vg. Fb jung? :) -- Whreq