(Some research on the ash shell "fast, small, POSIX-compatible Unix shell")
Noted from FreeBSD (and used in BusyBox)
HISTORY
A sh command, the Thompson shell, appeared in Version 1 AT&T UNIX. It was superseded in Version 7 AT&T UNIX by the Bourne shell, which inher- ited the name sh.
AUTHORS
This version of sh was originally written by Kenneth Almquist.