When I'm using terminal I can't type the letter "e". I can, however, type a capital "E" using either shift keys. The letter "e" won't work even if I copy command with the letter "e" in it. Very strange problem! Everything was working fine and I don't know what happened to it.
Not on my linux box right now, but just on the off chance have you checked what keyboard is configured in your local terminal? i.e. do you perhaps have the wrong keyboard configured. This article can help you check: https://superuser.com/questions/1300091/show-current-keyboard-layout