Thousands of application packages [p. 2]UI:UNIX are available for the UNIX system. A list of the various types of packages written for UNIX systems is included in the following table. The numbers were taken from [p. 10]UI:UNIX.
Table 1.2: UNIX Application Packages
In addition to the commercial packages, many programs are written
and made available in the public domain.
Examples of such packages are the X Window system, written at the
Massachusetts Institute of Technology and the 
system produced at
Stanford.
UNIX itself comes with a number of tools, including a calendar program, and a C beautifier.