<?xml version="1.0" encoding="utf-8"?>
<section id="GuideReferencePCRE">
  <title id="titleGuideReferencePCRE">Perl Compatible Regular Expressions</title>
  <para>
    The Filename and Comment sections on the search window use
    <ulink url="https://en.wikipedia.org/wiki/Perl_Compatible_Regular_Expressions">Perl Compatible Regular Expressions</ulink>
    . In general use there are a number of differences to the wildcard expansion used on the command line:
    <itemizedlist>
      <listitem>Use "." and not "?" for a single character.</listitem>
      <listitem>Use "abc.*ghk" and not "abc*ghk" for multiple characters</listitem>
      <listitem>Use "\." to represent the dot in a file extension</listitem>
      <listitem>Use "(?i)" to make the following characters case-insensitive</listitem>
    </itemizedlist>
  </para>
</section>