This simple function compares the current buffer with the saved file.
The function puts the result in a new buffer in the current session.
Use the `^` or `up` commands to return to the buffer.

    # Compare the current buffer with the saved file.
    # usage: <diff
    function+diff {
    db0
    H-
    ebvar+
    !true
    ebvar-
    etmp
    r+1
    W !diff -s - '_; true
    1
    }