Cant open file via terminal

mmm,

In terminal, when I type:

whereis python3

the path returned is /usr/bin/python3, but you have a different path output.

python3 --version

gives 3.7.3 for me (macOS 10.15.6)

Also something else a bit strange… pwd give you your path but the "d" in desktop should be "D" on a normal macOS install.

What filesystem attributes are you running? (case sensitive?) because it looks like you've made quite a few changes from a default ~/home environment.

If your PATH environment variable is not including your current directory location (as I do with mine), then you have to give Python3 some help by explicitly stating where the script is located:

python3 ./mama2.py

which is a shortcut for the current directory location.