Yash is a command line shell that conforms to the POSIX.1 (IEEE Std 1003.1, 2008 Edition) standard for the most part. Actually, it is much more POSIX-compliant than other shell like bash and zsh.

Yash also has its own features beyond POSIX, such as: * global aliases * random numbers * socket redirections and other special redirections * right prompt * command completion