These directories have examples from the Perl books:

advanced_perl	  "Advanced Perl Programming"
learning_perl/    "Learning perl"
learning_perl2/	  "Learning Perl, Second Edition"
learning_perlnt/  "Learning Perl on Win32 Systems"
PRK/              "Perl Resource Kit"
PRK/UNIX/	  "Perl Resource Kit, UNIX Edition"
programming_perl/ "Programming perl"
programming_perl2/ "Programming perl, Second Edition"