Es is an extensible shell. The language was derived from the Plan 9
shell, rc, and was influenced by functional programming languages,
such as Scheme, and the Tcl embeddable programming language. This
implementation is derived from Byron Rakitzis's public domain
implementation of rc.

Es is in the public domain. We hold no copyrights or patents on
the source code, and do not place any restrictions on its distribution.
We would appreciate it if any distributions do credit the authors.