Perl regex
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Computing: Programming: Perl: regex
This article explains regular expressions in terms understandable to mere mortals, and also how to use them in Perl.
Related Articles
- regex: manpage documentation
Details
Special characters in regex:
- . = any character
- * = 0 or more of previous character
- ^ = following string begins the line (except [^...] means "not these characters")
- $ = preceding string ends the line
- [] = list of characters which can satisfy the match at this position
- {} = # of repetitions of previous character
- () = part of input string to be plugged into variables ($1, $2, etc.)
- | = alternatives
- + = 1 or more of previous character
- a - b = range of characters from a to b (must be inside [] to be position-sensitive?)
Replacement variables generated by () are
- automatically numbered beginning with $1
- not local to the regex statement (i.e. they are available in subsequent lines of code)
Operators used to invoke regex:
- =~ returns TRUE if pattern matches
- !~ returns FALSE if pattern matches
- s/pattern/replacement/ replaces pattern with replacement
Examples
- Replace "thingy" with "stuffs" in $string:
- $string = s/thingy/stuffs/;