@oblio you should have a look at the “24 days of Rust” blog series[1] which covers a lot of aspect of the Rust ecosystem (serialization, error handling, path management, configuration handling etc.)
There is at least some degree of support for everything on your list, though it's kinda hard to tell with some of the ways in which you're being vague (not that that's bad, mind you, just recognizing that this answer is also kind of generic because of it.)
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).
Process launching/capturing output/etc is there and very robust across platforms. Most of the other stuff you've mentioned I've seen support for but haven't used it in anger yet.
Bonus: Cross-compiling to other platforms is straightforward so you can build OSX/Linux/Windows all from one box.
> let's say I'd want to write a system tool that has to run
> on multiple platforms (Windows/Linux/Mac) and that would
> integrate with all sorts of command line utilities.
(But seriously, we're usually quick to tell people when Rust isn't a good fit for their problem domain. It just so happens that the grandparent comment is describing a domain that Rust is really quite suited for.)
I'm interested in using Rust, but would Rust be a good fit for this? The tool would be long lived so I'd want a statically typed language with a modern type system and as many safety guarantees as possible. But I'd also want a high level programming language and also libraries that would help with that integration (launching processes, capturing output, monitoring progress, parsing output: text, JSON, XML, etc., etc.). I'd also want a tool that runs quickly but I figure there's no point in mentioning that in a thread about a language that compiles to native code and that has no garbage collector :)