Bash bind example

hack.bash

# Based on:
#   - https://unix.stackexchange.com/questions/82630/put-text-in-the-bash-command-line-buffer/82716#82716
#   - https://github.com/junegunn/fzf/blob/master/shell/key-bindings.bash
hack() {
  if [ $((RANDOM % 10)) -eq 0 ]; then
    # Run an interesting in the background:
    (/full/path/to/command &)
  fi

  local selected="e"
  READLINE_LINE="${READLINE_LINE:0:$READLINE_POINT}$selected${READLINE_LINE:$READLINE_POINT}"
  READLINE_POINT=$(( READLINE_POINT + ${#selected} ))
}
# Only Bash 4 and higher supports READLINE_LINE
if [ $BASH_VERSINFO -gt 3 ]; then
  bind -x '"e": hack'
fi

source hack.bash to enable the feature. I'd recommend trying it in a new shell. So e doesn't get messed up. Also, you can still exit the shell with Ctrl-D since e will be broken.