Example Regular Expressions

The following are regular expression examples which will match:

• An entire line.

        ^.*$

• Blank lines.

        ^$

• Whitespace on a line.

        \s+

• Whitespace across lines.

        (?n\s+)

• Whitespace that spans at least two lines. Note minimal matching `*?' quantifier.

        (?n\s*?\n\s*)

• IP address (not robust).

        (?:\d{1,3}(?:\.\d{1,3}){3})

• Two character US Postal state abbreviations (includes territories).

        [ACDF-IK-PR-W][A-Z]

• Web addresses.

        (?:http://)?www\.\S+

• Case insensitive double words across line breaks.

        (?i(?n<(\S+)\s+\1>))

• Upper case words with possible punctuation.

        <[A-Z][^a-z\s]*>