Crafting up a solution to POST an update from inside Servoy isn't exactly the "command line" type of solution I was looking for....like I said, if I wanted to hack around with HTTP, I'd use CURL....and as Johan has so kindly pointed out, this isn't really a stable way to do things anyhow.
Seriously though, when you have 30 or so different servers to update when you release, little things like being able to make a script to perform the update is a BFD. It's already kind of a pain that there is no supported way to upgrade Servoy to a specific build for when you need to update an app server to something other than the latest release, though to be fair, I'v heard that this may be changing. However, I've got a way to get around this, and can apply that update from the command-line. Other things that can be done via CLI include:
Turn off/on the app/db service
Update plugins
Sign/ReSign jars
SQL Scripts
So really, all that is missing from being able to be able to package up an update into a single script installer is, you know, actually being able to apply the code changes. This isn't a really crazy request by any standard, and I'm sure any ISV that does on site installations would agree. It's not like I'm asking for something awesome like having a built in way to deploy updates via an automatic download from a centralized server. That would just be insanity
I imagine it wouldn't be exceedingly hard to re-purpose the code that already exists to handle getting a file from the file system instead of POST data. If that code is part of the open source I'd be happy to look at it and implement my own if someone wants to point me towards the right area.