\d = any number
\D = anything but a number
\s = any space
\S = anything but a space
\w = any char (letter)
\W = anything but a char
. = any char, number
\b = blank space betwen words
\+ = one or more chars
? = 0 or 1 repetitions
* = 0 or more repetitions
{n}= exact number -> \d{5} represents five digits in a row
{n}= \d{1,5} between one and five digits
\e = Escape
\f = form feed
\n = newline
\r = Carriage return
\t = horizontal tab
calende[ae]r = search calender or calendar
[a-z] = any lower case letters
[0-9] = all numbers
[A-F] = any capital letters from A to F
