Can I run a terminal on IOS with sandboxed filesystem (w/o jailbreak)?
Sorry to resurrect an old question. . .

I was actually browsing for info on a new iOS app that sort of does just what this question is asking about, emulates a Linux environment via a pretty slick terminal app.

It's called iSH. Still in beta but I think you can get a Testflight invite right on the homepage. 

It even has pseudo access to the Files app.

For instance, you can make a directory with mkdir, create a script with the terminal using any number of editors, and then open said script in the Files app like it were an iCloud text document in your TextEdit folder. 

But, as far as I can tell, you can not move that script directly to Dropbox, or your TextEdit folder on iCloud.

You can, however, copy and share the text via the share extension.  

Anyone else been screwing with this app?

Here's the GitHub link to the project, and they've got a Twitter and reddit, too. 

A few screenshots of the app in action on an iPad with the Files app, and without: