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Regexp

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Regexp stands for regular expressions. Regular expressions are what made languages like Awk and Perl notorious. Regular expressions are expressions equating a pattern string. To write a regular expression in Perl on must insert it between slashes (/regexp/)For example:

/[a-z]/ 

means all the alphabet lowercase letters.

/[0-4]/

stands for all the digits from 0 to 4 inclusive.

/\d{2,5,7}/

stands for all the sequences of 2, 5 or 7 digits.

The interesting thing is that you can compose regexps into complex patterns. For example the regexp

/[A-Z]:[0-3]\.\S{1,8}/

describes a pattern that will match, for example, the strings B:1.HelloSir or 'A:0.Good. But it will not match a:2.darn because the first letter must be uppercase.

Bounding a whole word:

/\bWord\b/

See also