Examples

Only allow letters, numbers, exclamation point, and period

^[a-zA-Z0-9!.]⋆$

At most 8 characters long

^.,8$

Must start with a letter

^[a-zA-Z]

Must have a number

[0-9]

Must end in -admin or -test

(-admin | -test)$

Must begin with three capital letters and an underscore

^[A-Z] { 3 } _