In addition to what jamesjporter mentioned, Julia has IMHO a very nice, clean shell interaction paradigm for this very use case ("glue"):

http://julialang.org/blog/2012/03/shelling-out-sucks/

One of the best examples of this is the package manager's concise wrapping of git CLI commands:

https://github.com/JuliaLang/julia/blob/master/base/pkg/git....

(aside: there has been some discussing of moving to libgit2 for performance reasons)

Until recently, the startup time somewhat precluded use for general scripting. However, on the trunk the system image is statically compiled for fast startup, so scripting usage is viable.