[abc] | A single character of: a, b, or c |
[^abc] | Any single character except: a, b, or c |
[a-z] | Any single character in the range a-z |
[a-zA-Z] | Any single character in the range a-z or A-Z |
^ | Start of line |
$ | End of line |
\A | Start of string |
\z | End of string |
. | Any single character |