Some os commands (ls, ping...) not working after bootstrap

I'm having some trouble with my forked repo on my macOS Sierra. After installing, some commands like ls or ping don't work:

🔌 1:11 in .dotfiles/ on master
› ls
Traceback (most recent call last):
File "/usr/local/Cellar/grc/1.10_1/libexec/bin/grc", line 191, in
os.execvp(args[0], args)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/os.py", line 559, in execvp
_execvpe(file, args)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/os.py", line 604, in _execvpe
raise last_exc.with_traceback(tb)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/os.py", line 594, in _execvpe
exec_func(fullname, *argrest)
FileNotFoundError: [Errno 2] No such file or directory

Does anybody have a clue about what could be the problem?

Start by reviewing the bootstrap setup and reproducing the macOS Sierra failure shown in the traceback for ls and ping. Trace how commands are routed through grc and verify the resulting environment; done means those commands execute normally after bootstrap.