You can do anything with it because it allows launching other programs, but I'd say it was designed specifically for the domain of launching other programs and building data pipelines with their in- and outputs.
While DSLs are primarily designed to easily express certain idioms (e.g. Logo-family primarily describes pencil movement), generally (!), DSL is embeddable, isolated, Turing incomplete language. Although some DSLs are Turing complete, they are first and foremost designed to express domain specific idioms.
IMO Bash and friends are too powerful and generic to be considered DSLs.
