Perl Regular Expressions (Basics)

For a complete description look here.
To get some practice, click here.

Construct	Description
.	matches any character (except the new line)
\n	matches newline
\t	matches tab
\r	matches carriage return
\f	matches formfeed
\d	matches a digit (same as [0-9])
\D	matches a non-digit
\s	matches a whitespace character
\S	matches a non-whitespace character
\w	matches a word character (same as [0-9a-z_A-Z])
\W	matches a non-word character
\b	matches a word boundary
\B	matches a non-(word boundary)
^	matches the beginning of string
$	matches the end of string
expr1\|expr2	matches expr1 or expr2
expr*	matches any number of expr
expr+	matches 1 or more occurrences of expr
expr?	matches 0 or 1 occurrence of expr
expr{n,m}	matches at least n and at most m occurrences of expr
expr{n,}	matches at least n occurrences of expr
expr{n}	matches exactly n occurrences of expr
[class]	matches any of the characters in class
[^class]	matches characters not in class
(expr)	groups expressions
\\	matches `\'
\.	matches `.'

Some examples:

\bnik will match all words starting with nik, e.g., nikt, nikogo, but not panika;
\bnik(t|o(go|mu))\b will match exactly the words nikt, nikogo and nikomu (but not nikim);
\bsie\b.{0,15}\bsie\b will match any two occurrences of sie separated by at most 15 characters;
\bwydawac(\s|\d)+sie\b will match wydawac sie, with any number (but at least 1) of whitespace characters and/or digits between these two words;
\b[Kk](to\s+kogo|ogo\s+kto)\b will match Kto kogo, kto kogo, Kogo kto and kogo kto, with any number of whitespace characters between the two wh-words.

Maintained by Przemysław Kaszubski, based on an original page by Adam Przepiorkowski.

Last modified: 2004-11-03