Looks like you have to compile it yourself (meaning you need a mac with Xcode) or install it through testflight. Although I'm surprised that it's even allowed on testflight. iOS doesn't allow you to execute code of any kind locally, which is why if you download a "learn python" app or something it has to send your code off to a server, execute it, and then send you back the result.
It's part of the reason why I recently moved away from iOS. Things like this are not supposed to exist, and you have to bend over backwards to make it work.
EDIT: Okay apparently this changed as of last year-ish? Looks like they have an exception in place for "a programming environment intended for use in learning how to program"* Regardless I think this kind of shell environment is still against the app store guidelines.
It's part of the reason why I recently moved away from iOS. Things like this are not supposed to exist, and you have to bend over backwards to make it work.
EDIT: Okay apparently this changed as of last year-ish? Looks like they have an exception in place for "a programming environment intended for use in learning how to program"* Regardless I think this kind of shell environment is still against the app store guidelines.
*https://www.theregister.co.uk/2017/06/07/apple_relaxes_devel...