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  <H1 ALIGN="CENTER">Apache Server Frequently Asked Questions</H1>

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  $Revision: 1.114 $ ($Date: 1998/05/05 05:09:31 $)

  $Revision: 1.115 $ ($Date: 1998/05/20 11:12:42 $)

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  The latest version of this FAQ is always available from the main

   <LI><A HREF="#zoom">What's the best hardware/operating system/... How do

        I get the most out of my Apache Web server?</A>

   </LI>

   <LI><A HREF="#regex">What are "regular expressions"?</A>

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 <LI><A NAME="regex">

      <STRONG>What are "regular expressions"?</STRONG></A>

   <P>

   Regular expressions are a way of describing a pattern - for example, "all the words

   that begin with the letter A" or "every 10-digit phone number" or even "Every sentence

   with two commas in it, and no capital letter Q".  Regular expressions (aka "regexp"s)

   are useful in Apache because they let you apply certain attributes against collections

   of files or resources in very flexible ways - for example, all .gif and .jpg files under

   any "images" directory could be written as /.*\/images\/.*[jpg|gif]/.

   <P>The best overview around is probably the one which comes with

   Perl.  We implement a simple subset of Perl's regexp support, but

   it's still a good way to learn what they mean.  You can start by

   going to the <A

   HREF="http://www.perl.com/CPAN-local/doc/manual/html/pod/perlre.html#Version_8_Regular_Expresions">CPAN

   page on regular expressions</A>, and branching out from there.

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