What are some alternatives?
When comparing zsh and DASH, you can also consider the following products
fish - The friendly interactive shell.
Litecoin - Litecoin is a peer-to-peer Internet currency that enables instant payments to anyone in the world.
GNU Bourne Again SHell - Bash is the shell, or command language interpreter, that will appear in the GNU operating system.
Xiki - Xiki makes the command line friendlier and more powerful.
Bitcoin - Bitcoin is an innovative payment network and a new kind of money.
fshell - fshell is the Symbian equivalent of bash + telnet + a posix-like set of command-line tools.