- Metacharacters - Quantifiers
- ? Optional, zero or one
- + At least one, one to many (greedy)
- * Any amount, zero to many (greedy)
/^Subject: N?[0-9]+.*$/ Subject: 5 Cool Things Subject: 5551212 is my number Subject: N535GT
/^Subject: N?[0-9]+.*$/ Subject: 5 Cool Things Subject: 5551212 is my number Subject: N535GT