This is a very simple command line based shell for MicroPython. It is based on a stripped down version of cmd, which can be found here: https://github.com/micropython/micropython-lib/tree/master/cmd
I use it by copying cmd.py an shell.py to my sdcard. Then you can do:
This will automatically run it. If you want to reinvoke it, then use:
The shell has a notion of current directory, and you can use the cd command to move around.
Use help to find out available commands.
Note: If you are running an older version of Micropython, you should update it. A lot of the functions used were introduced recently.