shells/scsh - The NetBSD Packages Collection

Scsh is a Unix shell in that is has significant syntax extensions to
make writing Unix shell scripts easy (constructing pipelines, setting
I/O redirection, conditional execution etc.). It also offers access to
lower-level functionality like all Posix system calls, TCP/IP sockets
and a full-featured regular expression library. This is embedded into
a general-purpose programming language with real data types,
extensive, syntactically clean control constructs and "real" quoting
rules.

Scsh is also a full implementation of R4RS Scheme with some
non-standard behavior (required for scripting). As a result, a wide
variety of existing Scheme code can be used.

The underlying Scheme implementation is a virtual machine for compact
byte code.