. - Any one character
* - Match any number of previous (including 0)
+ - Match any number of previous
$ - End of the line
^ - Begining of the line
\S - Any non-whitespace charactor
\s - Any whitespace charactor
? - Optional
[a-z] - Any lowercase letter
[A-Z] - Any upppercase letter
[a-zA-Z] - Any letter
[0-9] - Any number # [5-9]