\
- special characters to literal and literal characters to special?
- matches zero or one times*
- matches zero or more times+
- matches one or more times{n}
- matches n times{n, m}
- matches at least n times, but not more than m times^
- matches at the start of the line$
- matches at the end of the line\s
- matches whitespace \S
- matches anything but a whitespace \f
- matches a form-feed\n
- matches a linefeed\r
- matches a carriage return\t
- matches a horizontal tab\v
- matches vertical tab\d
- matches any digit\D
- matches anything except digit\w
- matches any alphanumeric character including the underscore. Equivalent to [A-Za-z0-9_] \W
- matches any non-word character. Equivalent to [^A-Za-z0-9_] .
- matches any character except a newline