To maximize legibility, it is best not to abbreviate command
    keywords in a command procedure. Do not abbreviate command
    keywords to less than four significant characters (not counting
    the negation /NO . . . ), to avoid potential conflicts in future
    releases.

    Start a debugger command line at the left margin. (Do not start a
    command line with a dollar sign ($)  as you do when writing a DCL
    command procedure).

    The beginning of a new line ends the previous command line (the
    end-of-file character also ends the previous command line). To
    continue a command string on another line, type a hyphen (-)
    before starting the new line.

    You can enter more than one command string on one line by
    separating command strings with semicolons (;).

    To enter a comment (explanatory text that does not affect the
    execution of the command procedure), precede the comment text
    with an exclamation point (!).  If the comment wraps to another
    line, start that line with an exclamation point.