e each data line is passed to <b>pcre_exec()</b>, leading and trailing
whitespace is removed, and it is then scanned for \ escapes. Some of these are
pretty esoteric features, intended for checking out some of the more
complicated features of PCRE. If you are just testing "ordinary" regular
expressions, you probably don't need any of these. The following escapes are
recognized:
<pre>
  \a         alarm (BEL, \x07)
  \b         backspace (\x08)
  \e         escape (\x27)
  \f         formfeed (\x0c)
  \n    