Email Filtering

Matches Regex is if you wish to filter your mail using a Perl-style Regular Expression. If you don't know what that is, you're probably not going to be using it .

The numbers only entries are for numerical components of email such as spam score. The reason for "numbers only" is that a common implementation is to use a decimal number such as 2.1 for a spam score, however on most cPanel systems the decimal is ignored (mainly for more accurate comparisons) so what may be 2.1 on some systems is actually 21 on most cPanel/WHM systems.

If you were just doing a blank body, I'd use a rule "Body Equals" and leave the text field blank. However, gaging from your inquiry, you may need something more elaborate than that for what you specifically desire. Generally more elaborate rules make use of Regex as it is a very powerful (though non-intuitive) way of comparing text.

 

I wont recommend any specific website, but an Internet search for "Perl Regex Cheatsheet" will yield useful results.