Regular Expressions 101

break the code to first opening parenthesis and then closing use the groups individually not entirely . This is 40% correct online pattern but mixing it with first open then close groups in two different matches result in 100% success

verify if a string can be use in a username pattern for my project

This expression gives me the hostname for a given schema

Easy remove any , tag and inline styles for clean code

This will force a cidr block in the 10.x.0.0 range. Very useful if you restrict your cidr block to 10.x.0.0 in cloudformation (AWS).