Similar to UNIX_System_V

Procfs

Setuid

Single UNIX Specification

Termcap

Terminfo

Tz database

Udev

UNIX System III

The UNIX-HATERS Handbook

Unix-like

Unix wars

List of POSIX commands

X Window System

XFS

Xinetd

ZFS

Interix

Open system (computing)

Virtual console

Pseudoterminal

Getty (software)

Shell (computing)

Shell account

Shebang (Unix)

Sticky bit

Daemon (computing)