The Heirloom Toolchest is a collection of standard Unix utilities.
Highlights are:

* Derived from original Unix material released as open source by Caldera. 
* Up to four versions of each utility corresponding to SVID3/SVR4,
  SVID4/SVR4.2MP, POSIX.2/SUSV2, and 4BSD (SVR4 /usr/ucb).
* Support for lines of arbitrary length and in many cases binary input data. 
* Support for multibyte character sets, especially UTF-8. 
* More than 100 individual utilities including bc, cpio, diff, ed, file,
  find, grep, man, nawk, oawk, pax, ps, sed, sort, spell, and tar.
* The cpio utility can read and write zip files, GNU tar files, and
  the cpio formats of Cray UNICOS, SGI IRIX (-K), SCO UnixWare (-c)
  and Tru64 UNIX (-e). It is also available with the pax interface.
* Extensive documentation including a manual page for any utility. 
* Runs on Linux, Solaris, Open UNIX, and FreeBSD. 

WWW: http://heirloom.sourceforge.net/
