Should allow in the following format YY.MM (Years.Months)

psi

Minimum one capital, one special, one digit, no whitespace

STARTKEYWORD (.+?)(?:$| ENDKEYWORD$)

hh:mm 24

This should work: ^([a-zA-Z0-9]-[a-zA-Z0-9])+$ Also if you want to have exactly 135 hyphens: ^([a-zA-Z0-9]-[a-zA-Z0-9]){135}$...