Sendmail, 3rd Edition

Name

regex

Synopsis

The regex type allows you to parse tokens in the workspace using POSIX regular expressions. For information on how to use regular expressions see the online manuals ed(1) and regexp(1). A regex database-map type is declared like this:

Kname regex expression

The name is the symbolic name you will use to reference this database map from inside the RHS of rule sets. The expression is the literal text that composes your regular expression. Here is a simple example:

Knumberedname regex   ^[0-9]+<@(aol|msn).com.?>

The intention here is for this regular expression to match any address that has an all-numeric user part (the part before the <@), and a domain part that is either aol.com or (the | character) msn.com. To make rules that use this type easier to write, you can add a -a switch to the declaration:

Knumberedname regex -a.FOUND ^[0-9]+<@(aol|msn).com.?>

Here the -a database switch causes .FOUND to be appended to any successful match.

Note that because of the way we have declared this database map, nothing but the suffix will be returned on a successful match. To get the original key returned you need to also use the -m database switch (-m).

This regex type can use a number of switches to good advantage. The complete list is shown in Table 23-24.

Table 23-24. The regex database-map type K command switches

Switch	§	Description
-a	-a	Append tag on successful match
-b	See this section	Use basic, not extended, regular expression matching
-D	-D	Don’t use this database ...