'rm' not found in PATH or not executable

Well, at first thanks to the apport of https://unix.stackexchange.com/questions/115743/i-deleted-bin-rm-how-do-i-recover-it

sudo touch /bin/rm
sudo chmod +x /bin/rm
apt-get download coreutils
sudo dpkg --unpack coreutils*

You create a dummy file where the rm should be, an adds execution permission. You download the coreutils application (not sudo needed) and after that you install the files. dpkg will read coreutils package and make the install.