RegExpCheck is a free tool for testing the Perl-compatible regular expressions. The program takes on input a regular expression and a text string. If a string matches the specified pattern, all found matches are displayed in Results box. The strings are transformed to lowercase before matching, so the procedure is case insensitive. RegExpCheck does almost the same job as it's analogue in Perl: /<regexp>/ig

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System requirements:
Windows XP/Vista/7/8/10

See also:

Using rules for filtering spam

The lists of white and black rules are one of important mechanisms in filtering mail messages. Rules allow you to exactly identify a message as belonging to a certain class judging by the analysis of information in its headers or its body.