DB prompts for input with a "db>" prompt. Typing a control-z at
    any point while entering a command will cause DB to immediately
    stop execution. The quit-program command will also cause DB to
    stop execution.

    The rest of the command line after the "PMDF DB" will be scanned
    for DB commands separated by backslashes, \; i.e.,

    $ PMDF DB command1\command2...

    Each command specified will be executed from left to right as the
    command line is scanned. Placing commands on the invocation line
    is optional; if any are specified DB will terminate after the
    last one has been executed. If no commands appear DB will operate
    by prompting the user for commands.

    When first invoked, DB will open your personal alias database
    file which is pointed at by the logical PMDF_PERSONAL_ALIAS_
    DATABASE. PMDF establishes this logical at system startup as a
    system-wide logical equated with SYS$LOGIN:ALIASES.DAT. Users
    wanting to store their alias files elsewhere must redefine this
    logical for their process. Note, however, that relocation of this
    file will interfere with the proper operation of PMDF's public
    alias features.

    While entering DB commands to the "db>" prompt, the following
    command interaction features are available:

    o  Command abbreviation: commands can be abbreviated to their
       simplest, unambiguous form.

    o  Command completion: use the <TAB> key to automatically
       complete a command. If the command is ambiguous, it will be
       completed to the fullest extent possible.

    o  Command querying: at any point while entering a command, a
       question mark, ?, can be entered to obtain immediate help on
       what to do next or what options are available.

    o  Input files: command files can be input and executed by using
       the command <INFILE with INFILE the name of the file to input.
       When two angle brackets are used, <<INFILE, the commands read
       from the input file will not be echoed as they are executed.

    o  Logging: your session can be logged to an output file by using
       the command >OUTFILE with OUTFILE the name of the log file.
       All commands you enter and information printed by DB will be
       written to the log file. To log only the commands you type,
       use the command >>OUTFILE.

    o  DCL commands: typing a single dollar sign, $, will create and
       attach you to a spawned subprocess. To issue a DCL command
       from within DB, use the command $ DCL-COMMAND with DCL-COMMAND
       the DCL command you want to execute.