So it makes no fun!

(This app is ad-supported.) The basic function of the input of commands along with simple history is given. In "ls -l /" itself depends on the app (Kindle Fire HD 7, not rooted). The icons are misleading. So you can reach via the gear not Settings, via the "bug" no debugger and any folder view on the folder. The start button is a bit small and would be better realized as part of the keyboard. Instead, one can make multiple-line entries by pressing Enter. But the main problem is the lack of Android / OS Fire rights. One can not even "/ data / local / tmp" list, which is reached via the Developer Mode (USB). So Linux is not fun. But this is a limitation of Fire OS.