Sorry, I was in a bad mood. I should have written: This is now how you edit that file. You should edit this file using `visudo`, which "locks the sudoers file

Sorry, I was in a bad mood. I should have written: This is now how you edit that file. You should edit this file using `visudo`, which "locks the sudoers file against multiple simultaneous edits, provides basic sanity checks, and checks for parse errors" (quotes text from man page).