When comparing DASH vs Eshell (Emacs SHell), the Slant community recommends Eshell (Emacs SHell) for most people. In the question“What are the best UNIX shells?” Eshell (Emacs SHell) is ranked 4th while DASH is ranked 8th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Fast startup
Dash has a very fast startup, this happens because the shell is started a lot of times during boot and dash minimizes the work it does during this process.
Pro Low memory usage, which matters a lot in embedded
It is designed to be very lightweight and has no support for shell specific extensions that are not POSIX.
Pro Default shell on Debian systems
DASH is the default shell for Debian based systems due to it speed, full POSIX compliance and low overhead.
Pro Full POSIX support
It's fully POSIX compatible, so if your script runs on dash it will probably run on all other shells.
Pro A perfect clone
It's a clone of the original System V4 Bourne shell.
Pro Can invoke almost any elisp function loaded in Emacs
Pro Written in emacs lisp
Cons
Con Doesn't support all bash features
Dash does not support all bash features, sometimes called 'bashisms' unless explicitly pointed at /bin/sh
.