“Ed is the standard text editor.”

Let's look at a typical novice's session with the mighty ed:

    golem$ ed

    ?
    help
    ?
    ?
    ?
    quit
    ?
    exit
    ?
    bye
    ?
    hello?
    ?
    eat flaming death
    ?
    ^C
    ?
    ^C
    ?
    ^D
    ?

Note the consistent user interface and error reportage. Ed is generous enough to flag errors, yet prudent enough not to overwhelm the novice with verbosity.