Regular Expressions: Symbols and Modifiers

Symbols you can use in pattern matching:

Symbol What it matches . Matches any single character except newline [a-z0-9] Matches any single charecter of set [^a-z0-9] Matches any single charecter NOT in set \d Matches a digit (a number 0-9) \D Matches a non-digit (anything but 0-9) \w Matches an alphanumeric charecter (a-zA-Z0-9 and _) \W Matches a non-alphanumeric charecter \s Matches a whitespace character (space, tab, newline) \S Matches a non-whitespace character \n Matches a newline \r Matches a return \t Matches a tab \f Matches a formfeed \b Matches a backspace (inside [] only) \0 Matches a null character \b Matches a word boundary (outside [] only) \B Matches a non-word boundary ^ Anchors match to the beginning of a line or string $ Anchors match to the end of a line or string x? Matches 0 or 1 x's, where x is any of the above x* Matches 0 or more x's x+ Matches 1 or more x's x{m,n} Matches at least m x's, but no more than n (pat1|pat2) Matches either pat1 or pat2 (pat) Stores a pattern for backreferencing via $1, $2 through $9

Note: All other characters match themselves, except for these special characters: + ? / * ^ $ @ () [] | \ To match one of these, you have to use a backslash (e.g. "\@" matches "@"). m//, s//, and qr// operators all except the following modifiers after their delimiter: Modifier Meaning /i Ignore alphabetic case distinctions (case insensitive) /s Let . match newline and ignore deprecated $* variable /m Let ^ and $ match next to embedded \n /x Ignore (most) whitespace and permit comments in pattern /o Compile pattern once only s// specific modifiers: Modifier Meaning /g Replace globally, that is, all occurrences /e Evaluate the right side as an expression