
rgxg
rgxg is a command-line tool (and a C-library) that generates (extended) regular expressions. rgxg can be useful in generating (extended) regular expressions to match, for instance, a specific number range (e.g. 0 to 31 or 00 to FF) or all addresses of a CIDR block (e.g. 192.168.0.0/24 or 2001:db8:aaaa::/64).