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SAFEZIP.DOC
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1991-12-30
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S A F E Z I P
Version 7.2
by Brad Carlton
SafeZip is the quick and easy way to make sure that all subdirectories,
volume labels and read-only, hidden and system files are handled properly
when using PKZIP and PKUNZIP. I don't know how many times I have had to
ask the question "Did you use PKUNZIP with the -d option?" when somebody
complains about some program not working which had subdirectories.
SafeZip will even allow you to zip your DOS boot disk. Teledisk is NOT
required for a DOS boot disk, PKZIP and PKUNZIP work just fine when you
know what parameters to use. SafeZip also does automatic virus scanning
at your option.
Version 7.2 fixes another problem with virus scanning from SHEZ when
anything less than the entire zip was extracted. SafeZip 7.1 and earlier
scanned the zip itself rather than the files extracted from it. To fix
this problem, it was necessary to enhance the way parameters are parsed
by UNZ.EXE. It is no longer necessary that the path being unzipped to
be the 2nd parameter. UNZ now allows PKUNZIP options beginning with a
dash (-) to be used in front of the zipname and/or path to be unzipped
to. ZIP.EXE has also benefitted from this enhancement in version 7.2.
Version 7.1 started using the /A option when scanning for viruses.
The Flip virus has been known to elude detection when /A was not used.
NetScan can now be used rather than SCAN by specifying SAFEZIP=NETSCAN.
Also, a virus scan is now bypassed when the -T option detected, which
was annoying if UNZ was used from SHEZ, and files were tested from SHEZ.
Version 7 of SafeZip was mostly a bug fix for version 6, which added
support for SHEZ, but failed to automatically recreate volume labels on
diskettes when used from SHEZ. Version 7 fixed this problem. To fix
this problem, it was necessary to make SafeZip extract volume labels
whenever the current drive is a floppy, which is a damn good idea anyway.
So, this fix is also an enhancement for those who don't use SHEZ. At any
rate, UNZ.EXE can now REALLY be used as a PKUNZIP front-end in SHEZ so
that it is no longer necessary to exit SHEZ before running UNZ to unzip
files with all the parameters required to reproduce volume labels,
subdirectories and files with hidden, read-only or system attributes.
Version 7 also fixes a problem when virus scanning has been enabled with
the SAFEZIP=SCAN environment variable, and UNZ was being used from within
SHEZ. The virus scan did not work under these circumstances in ver. 6.
As promised, ZIP.COM has been replaced with ZIP.EXE, which is now
compiled with Turbo Pascal 6.0, as UNZ.EXE is. ZIP.EXE now also uses
the SAFEFLOP environment variable, which was introduced in version 6.
ZIP.EXE now automatically includes the volume label when the current
drive is a floppy, which is another enhancement over version 6.
ZIP.EXE is used to call PKZIP with all the magic parameters necessary to
create zips which preserve all the attributes of things such as DOS boot
disks. UNZ.EXE calls PKUNZIP to reproduce the files zipped with ZIP.EXE.
Command format: ZIP [-opts] zipname[.ZIP] [d[:]][\subdir] [filenames]
Please note that only the drive letter being zipped from needs to be
specified. The colon (:) is optional, so either "A" or "A:" will work.
ZIP.EXE also assumes that ALL files will be added to the zip, so it is
not necessary to specify "A:*.*". Simply "A" will do. ZIP.EXE adds this
wildcard filespec (*.*) to any filespec in the second parameter which is
a single drive letter, a drive letter and a colon and any filespec ending
with a backslash (\). The *.* is necessary to ensure that PKZIP includes
all subdirectories.
Volume labels are only included when zipping from a floppy disk.
ZIP.EXE only knows that you are zipping from a floppy if the filespec,
usually the second parameter, begins with a floppy drive letter or the
current drive is a floppy. Only drives A and B are recognized as being
floppies by default, but an environment variable can be set to override
this. IBM machines sometimes have a floppy drive D, so ZIP.EXE handles
this by looking for the SAFEFLOP environment variable. If A and D are
your floppy drives, then add the following command to AUTOEXEC.BAT:
SET SAFEFLOP=AD
The parameters used are mostly the same as if you were using PKZIP and
PKUNZIP directly. SafeZip just adds the parameters that are too easily
forgotten but required to practice safe zipping. If the drive and
subdirectory are omitted, it defaults to the current directory. The
"filenames" parameter is an optional list of files to be included.
Command format: UNZ [-opts] zipname[.ZIP] [d[:]][\subdir] [filenames]
Again, the drive letter being unzipped to can be specified without the
colon (:) for compatibility with previous versions of SafeZip. UNZ.EXE
is merely a front-end to PKUNZIP.EXE, and will pass all parameters to
PKUNZIP that were specified on the command line with the exception of
appending a colon to the drive letter being unzipped to, usually the
second parameter, if it is a single letter and thus a valid drive
specification. The "magic" that UNZ does if the drive being unzipped to
is determined to be a FLOPPY drive, is add the -$ option to the PKUNZIP
command line to ensure that any volume labels, if present, are recreated
on the floppy disk. Version 7 has added an exception to this rule,
however. Now, if the current drive is a floppy drive, the volume label
WILL be extracted even if the drive letter was not found in the second
parameter. As mentioned above in reference to ZIP.EXE, UNZ also assumes
that only drives A and B are floppies, but UNZ also reads the SAFEFLOP
environment to override this.
The -$ option is not the only thing UNZ automatically adds to the PKUNZIP
command line. The -D and -JHSR options are also added to ensure that
subdirectories and files with hidden, system and read-only attributes are
recreated properly. These options are used on both hard and floppy
drives, unless it is determined that UNZ is being used to unzip temporary
files from within SHEZ. In this case, the command line is passed to
PKUNZIP without the -$, -D or -JHSR options. These options ARE used from
within SHEZ when appropriate for files being unzipped normally. This
support for SHEZ was the main reason UNZ was rewritten in Pascal for
version 6. To use UNZ from SHEZ, just configure SHEZ to call UNZ.EXE
rather than PKUNZIP.EXE.
UNZ also does automatic virus scanning with McAfee's SCAN.EXE. This
option is enabled by setting SAFEZIP=SCAN in AUTOEXEC.BAT. Again, UNZ
requires that the location of the unzipped files be specified as the
second parameter so that it can pass this information to SCAN. However,
if ONLY the zipname is specified, so that the files are unzipped to the
current directory, UNZ will tell SCAN to search the current directory by
using *.* as the filespec. In SafeZip version 7, UNZ now also recognizes
that it is running from SHEZ, and also uses the *.* filespec in this
case. UNZ uses the SCAN /SUB option to search subdirectories of the
directory unzipped into for viruses, so this will, of course, result in
your whole drive being scanned if you unzip into the root directory.
SCANV80 or above is required if SAFEZIP=SCAN is set because the /SUB
option was added in v80.
Starting with version 7.1, the SAFEZIP environment variable can be set
to SCAN, NETSCAN, or to whatever your copy of SCAN is named. It is not
yet possible to customize the parameters passed to SCAN without editing
UNZ.EXE with a sector editor such as Norton DiskEdit, but hopefully
SafeZip version 8 will have this capability.
Well, thats about it. SafeZip is a free utility, and the latest version
is always a free download on Mother Lode. If you don't have an account
on Mother Lode, you should! If you would like the number and NUP for
Mother Lode, please leave a message to Brad Carlton on SpamLand, The
Realm of Immortality, 10 Downing, Wastelands III or Paradise Springs.