...Due to the developer / maintainer of Terminal-IDE moving on, I'm trying to find equivalent capability and after hours of research found "Terminal Emulator for Android" (which is the same app as "Android Terminal Emulator"). But of course, it doesn't have all the tools necessary. I looked for some hours - not an exhaustive search but how many hours are you going to look?! - and found nothing that appears to have the tools already built in (other than Terminal-IDE).
Rather than develop them myself, I found K-Box which provides "standard Linux utilities in a stock, non-rooted Android device" and which has its main example using the Android Terminal Emulator as a starting point. Sounds perfect!
I was following the basic directions there, however, I can't hardly get started because I can't seem to find the path to the "Downloads" directory?! Frustrating.
In doing my research, I found this interesting and thoughtful writeup, but didn't get to a successful answer.
To be clear, to get this installation going, I have to transfer a file from ANY LOCATION into the Terminal Emulator environment, and that brings the tools that then make the terminal emulator more of a real Linux environment on the Android. The location does not have to be "Download", but that directory was easily enough mapped by my desktop computer's file system browser upon plugging in the USB connector... In fact, that's how I installed the Terminal Emulator - by putting the apk file (and for several other "side load" apps) into Download and then telling Android to install them. So the real trouble is, I can't seem to find that location from within the Terminal Emulator!
Locations I can find but for which I have no permissions include:
/storage/emulated /data/media/0/Download /data/media/0/Downloads
In each case, it returns: