Determining UNIX Versions
Before you can begin adjusting shell scripts to be portable, you need to know what the different types of UNIX are and how to tell them apart. The three major types of UNIX are
BSD (Berkeley Software Distribution)
The locations of commands and the options supported by certain commands are different among these three types of UNIX. This chapter highlights some of the major differences pertaining to commands in particular.
UNIX was first developed in the 1970s at AT&T's Bell Labs. For many years it remained restricted to AT&T and a few universities. In the early 1980s, the University of California at Berkeley acquired the source code to UNIX from AT&T Bell Labs. Throughout the 1980s and into the early ...