UNIPAK/UNIUNPAK

                                    by  Douglas E. MacLean
                                        2200 Ocean Avenue Apt. 6B
                                        Brooklyn, New York 11229
                                        SysOp on the Vernon BBS
                                        (201) 827-6441
                                        1200/2400 24 hours a day





    With the advent of the ZIP compression format, many programs will
    have to be modified to recognize both ARC and ZIP file formats.
    UNIPAK and UNIUNPAK are universal programs that will decide with
    format to use and call to correct program.  For example:


                uniunpak -v qmail.qwk

    will view the files in the archive.  If qmail.qwk was compressed
    with pkzip than the command executed will be:

                pkunzip -v qmail.qwk

    If the pkpak program was used the command executed would be

                pkunpak -v qmail.qwk

    All of this is transparent to the user.  In a qmail reader, door or
    any program that uses archiving, substitute the universal command in
    the file that designates the compression program to use.  You will
    than be able to unpack any type of file.

    Since the options for compression are more complicated that unpacking
    the UNIPAK program uses three environmental variables to permit
    the user the most control possible.  If now extention (ARC or ZIP) is
    provided than the default will be to make a ZIP file.  This can be
    overriden by the use of the UNIDEF environmental variable.

                set UNIDEF=arc

    will tell UNIPAK to default to ARC format if no file type is given in
    the filename.

                unipak -a source *.c

    will process all 'C' files into a compressed file named "source".  If
    the UNIDEF variable was not set "source.zip"  will be created.  If the
    UNIDEF variable was set to arc as above the file created will be
    "source.arc".
    

    The zip format offers options to control the compression degree and
    the speed of the compression.  These options can be set in UNIPAK by
    using the UNIBIN and UNIASC variables.  UNIBIN controls the
    binary compression while the UNIASC variable controls the ascii
    compression.
    
    
                set UNIBIN=-eb4
                set UNIASC=-ea4

    This will tell UNIPAK to ZIP files using these compression parameters.

    The UNIUNPAK program will now take the default type from the UNIDEF
    variable.  COmmands like:

                uniunpak test *.txt

    will extract the txt files from whatever type of file test is.

    If the wrong file type is given to a program it will attempt to
    determine the correct file type.  For example, if an application
    forces the zip extent on a file name and you are trying to view
    the contents of the file test.arc  the command

                unipak -v test.zip

    the UNIPAK program will look to see if test.zip exists.  If it doesn't
    it will look for test.arc.  If this is found the correct routine
    is called to list the files in test.arc.