The Bourne shell was a relative latecomer to UNIX, released in 1979, replacing the [Ken] Thompson shell. It lacks many things provided by a POSIX shell (nearly

The Bourne shell was a relative latecomer to UNIX, released in 1979, replacing the [Ken] Thompson shell. It lacks many things provided by a POSIX shell (nearly all of which are present in the later Korn shell). There are many entire operating systems that survived only a fraction of this time. I think that it will remain relevant for decades. https://en.wikipedia.org/wiki/Bourne_shell https://en.wikipedia.org/wiki/Bourne_shell