The Bywater BASIC Interpreter (bwBASIC) implements a large superset
of the ANSI Standard for Minimal BASIC (X3.60-1978) and a significant
subset of the ANSI Standard for Full BASIC (X3.113-1987), and many
classic BASIC dialects in C.

bwBASIC can be configured to enable commands, functions, operators
and punctuation characters available in many classic dialects of BASIC;
these are controlled by various OPTION commands.  bwBASIC does not attempt
bug-level compatibility with any particular BASIC dialect nor does it
currently support graphics.  bwBASIC seeks to be as portable as possible.

It also offers shell programming facilities as an extension of BASIC.