I would say Tcl!
Tcl is one of the most underrated programming language that everybody probably has installed. It has existed for as long as ksh and even long before bash. It is simple and powerful enough that first version of Redis were written in it.
MacPorts is written in Tcl (including its ports DSL) and I enjoyed every moment working with it.
The syntax takes some adjustment because it's not lval/rval-based, which is maybe why it's not so widely used now. But if you want a language that's more robust than shell and more minimal than Python, consider TCL for your next project.