I'm not quite sure what you mean when you say "integrate with all sorts of command line utilities", but based on the other things you write I could not think of a better language than Rust.

Since I started to write some Rust code about 6 months ago, Rust has replaced Python as the language I think in. Static typing with a modern typing system is awesome, and not having to think about a GC is also awesome (see also the recent Medium article about all the ways GC's need to be tunable).