what is the command line interface shells for a freeware functional clone of sh, with parts of ksh, bash and full POSIX compliance, and many new interactive command-line editing features. It was installed as the default shell on early MacOSX systems.

Answer 1

The command line interface shell you are referring to is called "zsh" (Z Shell). It was developed by Paul Falstad in 1990 as a freeware functional clone of sh, with parts of ksh, bash and full POSIX compliance, and many new interactive command-line editing features. It was installed as the default shell on early MacOSX systems.