Regex Reference
[a-m]Character from a to m .Any character *0 or more
[N-Z]Character from N to Z \wAny word character +1 or more
[0-6]Digit from 0 to 6 \dAny digit ?0 or 1
[xyz]x or y or z \sAny whitespace character {4}Exactly 4
[^a]Not a \bWord boundry {4,}4 or more
[^xy]Not x or y \x52Hex character 0x52 (R) {4,7}Between 4 and 7
(ab|xy)ab or xy \130Octal character 130 (X) (...)Capture group