To learn regular expressions for use in
<DirectoryMatch> or equivalent sections, the
book Mastering Regular Expressions, by Jeffrey
E. F. Friedl (O'Reilly), may prove to be an
invaluable resource.
Chapters 4 and 8 of Professional Apache,
by Peter Wainwright (Wrox
Press), explain how to configure Apache the way you want and improve
Apache's performance.
Chapter 8 of Writing Apache Modules with Perl and
C, by Lincoln Stein and Doug MacEachern
(O'Reilly), talks extensively about configuration
customization with mod_perl.
mod_macro
is a module that allows the definition and use of macros within
Apache runtime configuration files. The syntax is a natural extension
to Apache HTML-like configuration style. It's very
useful if you have to configure many sections (e.g., when you have
many virtual hosts) and haven't learned about
<Perl>sections yet.