PySh is a planned roughly POSIX-compliant shell with various built-ins to allow portability of the test suite.

Some useful links:

[http://pyparsing.wikispaces.com/ Pyparsing]: an easy-to-use recursive descent parser as a single Python module.

[http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_10 POSIX shell BNF]: a good starting point for building our shell grammar

[http://pyparsing.wikispaces.com/space/showimage/ebnf.py ebnf.py]: An EBNF->pyparsing converter