Apache - Apache Software Foundation Distribution Directory.
CPAN - Comprehensive Perl Archive Network.
Crux - Lightweight Linux distribution for the x86-64 architecture targeted at experienced Linux users.
CTAN - Comprehensive TeX Archive Network.
Cygwin - a large collection of GNU and Open Source tools which provide functionality similar to a Linux distribution on Windows.
GNU - GNU is an operating system that is free software—that is, it respects users' freedom.
Htdig - WWW Search Engine Software.
Knoppix - a bootable Live system on CD, DVD or USB flash drives, consisting of a representative collection of GNU/Linux software.
LDP - The Linux Documentation Project.
PuTTY - a free implementation of Telnet and SSH for Windows and Unix platforms.
Vim - a professional text editor. It can be used to edit plain text in a highly productive way.
X - a open source implementation of the X Window System.