I received this error when I modified the
/etc/environment file and changed the PATH variable.
I went to this to solve the problem.
On the login screen Press CTRL+ALT+F1, then type in your regular name and password.
If you get something like "
/bin is unavailable" because it's not included the PATH environment then you need to go to you
/etc/environment file and see if it looks like this
I had extra lines because I was trying to add java to the path
If you type in
you will be able to us the ls command but that will only be for this login session
I edited that file with the pico editor
sudo pico /etc/environment
saved it, logged out and the pressed CTRL+ALT+F7 to get back to the graphic log in and was able to log in.