an implementation of the AT&T Plan 9 shell

 rc is a command interpreter and programming language
 similar to sh(1). It is based on the AT&T Plan 9 shell of the
 same name. The shell offers a C-like syntax (much more so
 than the C shell), and a powerful mechanism for manipulating
 variables. It is reasonably small and reasonably fast,
 especially when compared to contemporary shells. Its use is
 intended to be interactive, but the language lends itself well
 to scripts.