Recs.
Updated
DASH is a POSIX-compliant implementation of /bin/sh that aims to be as small as possible. It does this without sacrificing speed where possible. In fact, it is significantly faster than bash (the GNU Bourne-Again SHell) for most tasks.
Specs
Pros
Pro Default shell on Debian systems
Dash is the default shell for Debian based systems (which includes Ubuntu).
Cons
Con Doesn't support all bash features
Dash does not support all bash features, sometimes called 'bashisms' unless explicitly pointed at /bin/sh
.
Con POSIX shell syntax is outdated
Purely POSIX shell syntax is useful for executing legacy scripts, but the POSIX syntax has a number of shortcomings that negatively effect usability and usefulness. For example, modern day shells need to do more than just execute commands and redirect I/O. They also need to feature first class text manipulation capabilities, and having a clean syntax for scripts increases long-term readability. Performing more advanced text manipulation requires spawning a lot of subshells, which negatively effects the performance of Dash scripts.