Full Interprocess Communications
The Command Line
Many, Many More Functions
Many, Many Predefined Variables
Symbol Table Manipulation with *FRED
Additional Regular-Expression Features
And Other Stuff
Yes, it's amazing. A book this long, and there are still some things that it didn't cover. The footnotes contain additional helpful information.
The purpose of this section is not to teach you about the things listed here, but merely to provide a list. You'll need to go to Programming Perl, the perl (1) or perlfaq (1) manpages, the HTML documents in CPAN's doc directory, or the Usenet newsgroups to get further information.
Yes, Perl can do networking. Beyond the TCP/IP stream sockets discussed in Appendix C, Networking Clients, if your system is up to it, Perl also supports UNIX-domain sockets, UDP-based message passing, shared memory, semaphores, named and anonymous pipes, and signal handling. See Chapter 6 of Programming Perl or the perlipc (1) manpage for standard modules, and the networking section of the CPAN modules directory for third-party modules.
Yes, Perl can do TCP/IP socket networking, UNIX-domain networking, and shared memory and semaphores on systems that support it. See the perlipc (1) manpage for further information.