Dec 132017
 
General Unpack Shell v1.95 - unpack / test / view archive files - ARJ LZH ZIP PAK ARC SQZ UC2 RAR HA HAP ... - Shareware. Nice.

Full Description of File


General Unpack Shell (GUS) v1.95 handles 15
archive types and their self-extractors.
(ARC ARC+ ARJ DWC HA HAP HPK HYP LZH PAK RAR
SQZ UC2 ZIP ZOO & SFXs)
New in this version:
- small GUS header in case of redirection;
- virus scan of unpacked files;
- option to move bad or unknown archives
elsewhere;
- "personalized" GUS for registered users.


File GUS_195.ZIP from The Programmer’s Corner in
Category Recently Uploaded Files
General Unpack Shell v1.95 – unpack / test / view archive files – ARJ LZH ZIP PAK ARC SQZ UC2 RAR HA HAP … – Shareware. Nice.
File Name File Size Zip Size Zip Type
FILE_ID.DIZ 357 267 deflated
GUS.DOC 80328 25107 deflated
GUS.EXE 14978 14047 deflated
GUS_WCFG.PAS 7026 1590 deflated

Download File GUS_195.ZIP Here

Contents of the GUS.DOC file









General Unpack Shell
version 1.95 for DOS

Copyright (C) 1995 and written by
Johan Zwiekhorst
- ALL RIGHTS RESERVED -



T A B L E O F C O N T E N T S
*********************************

1. LEGAL STUFF
The No-Nonsense Licence Statement
Warranty
Contact
Cost and Payment
What you should have received

2. INTRODUCTION

3. USAGE
3.1. General Usage under DOS
SYSTEM REQUIREMENTS
COMMAND-LINE PARAMETERS
NOTE
EXAMPLES
EXIT CODES
3.2. Unpacking Mailarchives
3.3. Identifying Archive Types

4. BUILT-IN DEFINITIONS
4.1. Built-in Child Program Definitions
4.2. How To Define Other Unpackers

5. GUS & OTHER SHELLS

6. HOW GUS IDENTIFIES ARCHIVES
6.1. Recognition patterns as used by GUS
6.2. Record layout of ARC/ARC+/PAK
6.3. How GUS identifies SFX (self-extracting) archives
6.4. Mandatory order of scanning recognition patterns

7. RUNTIME MESSAGES
[A] General information messages
[B] Warning messages (non-fatal errors)
[C] Fatal error messages

8. ACKNOWLEDGEMENTS

9. REVISION HISTORY



1. LEGAL STUFF


This software is copyrighted (C) 1989, 1990, 1991, 1992, 1993, 1994,
1995 and written by Johan Zwiekhorst, hereafter called the Author and
Owner. All Rights Reserved.

The No-Nonsense Licence Statement
=================================
This software and everything enclosed with it are protected by both
Belgian copyright law and international treaty provisions.
It is called "shareware".

SHAREWARE software may be copied and distributed freely IF:

* NO FEE IS CHARGED FOR USE, COPYING OR DISTRIBUTION
(you may recover media and postage expenses, however)

* IT IS NOT MODIFIED IN ANY WAY.

It may be distributed ONLY in it's original, unmodified compressed
package file. ~~~~~~~~~~

This means you may not add comments to the compressed package file
(also known as an archive file or simply an archive), nor may you
delete files from or add files to the archive file, UNLESS YOU HAVE
A WRITTEN PERMISSION TO DO SO.

Converting the archive file to another compression method or another
archive file format is allowed, provided that the above conditions
are met.

The original package as released by me is a self-extracting RAR
type archive with authenticity verification. RAR is a Russian
archiver that compresses very well. I made the archive self-
extracting because I couldn't be sure that everyone would have
RAR.EXE or UNRAR.EXE.
At the time this is written, the latest version of RAR is 1.52, so
look for RAR1_52.EXE. The small freeware UNRAR program is available
in both a DOS and an OS/2 version. The DOS program can be found
inside the RAR1_52.EXE package; the OS/2 program is available as a
separate archive called UNRAR100.ZIP.
Note, that recompressing the original GUS archive could result in a
bigger archive.


Warranty
========
This software is provided AS IS without any warranty, expressed or
implied, including but not limited to fitness for a particular
purpose.
IN NO EVENT SHALL THE AUTHOR/OWNER OF THIS PRODUCT BE LIABLE FOR
ANY DIRECT OR CONSEQUENTIAL LOSS OR DAMAGES WHICH MAY HAVE ARISEN
FROM THE USE OF THIS PRODUCT.
If your local law does not permit any of the statements made above,
or if you do not agree with any of them yourself, THEN YOU ARE NOT
LICENCED TO USE THIS PROGRAM!


Contact
=======
The Author can be reached via a Bulletin Board System (BBS) and
electronic mail at the Tripod BBS.

Phone lines:

[due to a move, none are currently available]

Network addresses:


Internet [email protected]

Compuserve >INTERNET:[email protected]

FIDOnet 2:292/100
2:292/118


Main support BBS:
(please call this system while Tripod BBS is off-line)

Tornado Belgium BBS, sysop Frank Van Uffelen

Phone lines:

+32-16-640582 V.34
+32-16-640465 V.34
+32-16-640466 V.32bis

Network addresses:

Internet [email protected]

Compuserve >INTERNET:[email protected]

FIDOnet 2:292/600


The Owner can be contacted at the following address:

Johan Zwiekhorst
Dorpheidestraat 63
3590 DIEPENBEEK (Belgium)
Phone [not yet available] during office hours, Central European Time.


Cost and Payment
================

COMMERCIAL
~~~~~~~~~~
If you would like to use this product in a commercial or
governmental situation, please contact the Owner at the address
above. You will then learn the price of the product and a
Commercial Licence Statement will be made available to you.
The price of the product varies with the number of licences ordered.

NON-COMMERCIAL
~~~~~~~~~~~~~~
For all others, a small contribution is asked.
This contribution supports the Author and encourages him to write
more useful software and keep developing this product.
Note that this kind of shareware products is developed entirely in
the Author's leisure time and he receives absolutely no compensation
for it, apart from what you as a user would pay him.
I don't believe in crippling the software or otherwise annoying you
into paying. If you want to keep using it but not pay for it, so be
it. It's not a very nice attitude, but I'll live.
Any natural person who really can't afford to pay, is hereby allowed
to use it for free.
(Note: if you can afford to buy cigarettes, beer or tickets to your
local movie theatre regularly, you can also afford to pay for this
software.)
This software may also be used for free by those who have made a
substantial contribution to the Fidonet community, as Vince Perriello
and Bob Hartman have by creating the BinkleyTerm mailer. Here's to
ya, guys!
If you think you deserve to use this software for free as well, then
write to me.

You may pay whatever you feel this software is worth.
If you pay at least U.S. $15 (BEF 500, NLG 30, DEM 25), you will
receive a 3.5" floppy diskette with a personalized "registered"
version of GUS.
Immediately after receiving your payment, I will send you an acknow-
ledgement and a list of the latest versions of all freeware I wrote,
unless my postage and handling would cost me as much or more than
what you paid.

Payments to the Author can be sent in cash (no coins please!) to the
address mentioned above or transferred to the following bank account:

Bank Brussel Lambert (Belgium) - account number 335-0076382-89

People outside Belgium: the cheapest way in which you can pay is
as follows...
Go to your bank and ask for one banknote of 500 Belgian franks.
It will have a blue print. Put the banknote in an envelope together
with a nice letter expressing your immense gratitude for creating GUS
๐Ÿ™‚ and send it to me. Make sure the banknote is not visible through
the envelope!

***NOTE THAT THIS IS FOR NON-COMMERCIAL SITUATIONS ONLY!

For all payments made: please specify NAME and VERSION NUMBER of
the product!

Payments are valid for THREE sub-versions of the software.
(The number before the dot in the version number indicates the main
version, the digit right after the dot is the sub-version and the
digit after that one indicates a patch or bugfix.)
This means that if you paid for version 1.6x, your payment is valid
until version 1.90 is released - then you should renew it.

Consider this: GUS v1.00 was released in 1989 and GUS v1.95 in 1995.
So we're talking about 10 sub-versions (0 to 9) in 6 years. If this
licence had been valid from day one, you should have paid three times
for GUS in these six years. That also means that GUS would cost you
an average of about $7.50 per year. Not exactly backbreaking, is it?

Contributions received thusfar for GUS:

NON-COMMERCIAL COMMERCIAL
~~~~~~~~~~~~~~ ~~~~~~~~~~
Belgium : 8 people (none)
Canada : 1 person
Italy : 1 person
Netherlands : 1 person
United Kingdom: 1 person
United States : 2 people

Impressive, huh? :-}


What you should have received:
==============================

You should have received the file

GUS_195.EXE - (47275 bytes)

with the following contents:


filename bytes description

FILE_ID .DIZ 357 Short description for BBS sysops.
GUS .DOC 80328 This documentation.
GUS .EXE 14978 The program file. CRC/32 = d26e8d16
GUS_WCFG.PAS 7026 TP source for a program CRC/32 = b2068b2f
that writes a new configur-
ation into GUS.EXE.

While viewing, testing or unpacking this self-extracting RAR archive,
it should display the following message on your screen:

Verifying authenticity information ... Ok

Archive GUS_195.EXE
modified at 19:50:00 15 Mar 1995
by Johan Zwiekhorst


You may also use the program VALIDATE from McAfee Associates for
the purpose of checking the authenticity of the program file(s).
It should produce the following if you're using VALIDATE v0.4:

File Name: gus.exe gus_wcfg.pas
Size: 14,978 7,026
Date: 3-15-1995 3-15-1995
File Authentication:
Check Method 1 - CED2 7171
Check Method 2 - 0EF3 0A9A

and the following if you're using VALIDATE v2.00 and up:

Validate version 2.00 Copyright (c) McAfee, Inc. 1994.
All rights reserved. (408) 988-3832 EVALUATION COPY
Directory of GUS\

GUS EXE 14978 03-15-95 19:50 2D91 72E9
GUS_WCFG PAS 7026 03-15-95 19:50 4DF9 74D0

3 file(s) were validated


GUS is available for several operating systems:


system look for comment

DOS GUS_*.* current release: GUS_195.EXE
OS/2 GUS2_*.* (will be available starting with v2.00)
Win/NT GUSw_*.* (not yet available, but does anyone want this?)



2. INTRODUCTION


The General Unpack Shell, or GUS, identifies compressed file types
and calls the correct unpacker in order to extract the files from
them.
Its main purpose is, of course, to take work out of YOUR hands.
You can use GUS with its straight-forward and easy to remember
commands instead of having to learn a new set of commands each time
a new archiver sees the daylight.

GUS will also work nicely in automated tasks, where any type of
archive has to be uncompressed, or where a certain file should be
added to any given archive.

GUS was made to be command-line compatible with the ARCE.COM
unpacker program by Vernon Buerg. This makes it possible for you
to rename GUS.EXE to ARCE.COM and have it invoked by any program
that expects both ARCE and SEA's ARC-type compressed files, so that
such a program will in fact work with any archive format YOU
choose. Ben Baker's MAKENL is but one example of such a program.

GUS does not require you to fiddle with cumbersome and difficult
configuration files: it's just a single EXE file. You copy it into
your favourite utility directory and you can immediately start
using it, no hassles at all.



3. USAGE


GUS assumes you have located all archiver programs it has to invoke
somewhere in your system PATH.
GUS is small and it will only occupy about 30K while shelling out
to other programs, which should leave more than enough memory for
those archiver programs.

3.1. General Usage under DOS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SYSTEM REQUIREMENTS:
--------------------
GUS will run on any IBM PC compatible computer running DOS 3.0 or
greater, provided that at least 32K plus the memory needed by the
largest archiver program to invoke is available.

COMMAND-LINE PARAMETERS:
------------------------
As said before, GUS is command-line compatible with ARCE.
Hence, the general syntax is:

GUS compressed_filespec [filespec(s)] [target_path] [switch(es)]

(Entries enclosed within [] are optional, those within are
mandatory. The [] and signs serve to indicate this only and
should never be typed!)

compressed_filespec ::= this specifies where to find the
compressed file. If an extension

is not given, GUS will assume '.*'.
Currently, the following archive types
are supported: ARC and ARC+, ARJ, DWC,
HA, HAP, HPK, HYP, LZH (both LHarc and LHA),
PAK, RAR, SQZ, UC2, ZIP and ZOO.

[filespec(s)] ::= specifies which files should be
unpacked. You may give more than one
file specification, all of which may
contain wildcards.

[target_path] ::= specifies where to locate the unpacked
files. In order to allow GUS to be as
flexible as possible, the ordering of
the file specifications and the target
path is not important. You may define
the target path first and then the
files to be extracted. It is even
allowed to put the target path in the
middle of a number of specifications of
files to extract! If you give more
than one directory, GUS will ignore all
but the last.

[switch(es)] ::= specifies one or more of the following
switches...
/D : Delete archive after successful unpacking
/I : Identify only, don't shell out (see 3.3 below)
/M : unpack Mailarchives only (see 3.2 below)
/N : do Not use embedded path while extracting
(for the sake of compatibility with ARCE, /5 may also be
used)
/P : Print file(s) on standard output device
/Q : Quiet mode, suppresses shell output
/R : Replace existing files
/S : Scan for viruses in unpacked files
/T : Test archive integrity
/V : View archive contents
/Bdir : Bad archives will be moved to the specified directory
/Gpswd : supply password 'pswd' for Garbled archive

All parameters have to separated by at least one blank. Switches
may be joined together without spaces, but the '/' character must
be present for each switch. GUS does not support the dash '-'
instead of the slash '/'.
Options may be given in no matter what case. Only the Delete option
_has_ to be in uppercase for safety reasons.

NOTE:
-----
Consistent with ARCE's behaviour, GUS will create any directories
contained within an archive if they do not exist. Both ARCE and GUS
have a commandline switch with which you can prevent this and have
them extract to the current directory.
If you are using the /M (mail archive) switch however, use of the
/N (No embedded paths) switch is automatically assumed and unpacking
will always be done in the specified inbound mail directory.
With /M, the option /D (Delete archive after successful unpacking) is
also automatically selected.
The /N switch is equally automatically invoked with /P (print) and /T
(test).
Since SEA's XARC program cannot list the directory of an ARC+ (A7+)
archive, GUS will switch to the program configured for the regular
ARC type instead in order to execute the View Contents command.

EXAMPLES:
---------
1) Extract all files from an archive CFILE.ANY:
> GUS CFILE.ANY

2) Extract all *.COM and *.EXE files from an archive UTILS.ANY
into a target directory D:\Utils, replacing all existing ones
and performing a virus scan on the unpacked files:
> GUS UTILS.ANY *.COM *.EXE D:\UTILS /R/N/S

3) A batchfile LA.BAT which will list any text file inside any
archive:
LA.BAT: @echo off
GUS %1 %2 %3 %4 %5 %6 %7 %8 %9 /P|LIST/S

Now you can use this: LA KBUI_202 *.DOC

4) Test the integrity of all archives in the directory F:\Arcs
> GUS F:\ARCS\* /T

5) Unpack all ZIPfiles PW*.ZIP protected with password JiMmY into
the directory D:\PWS, not replacing any existing files and using
embedded paths, if any:
> GUS PW*.ZIP D:\PWS /GJiMmY

EXIT CODES:
-----------
GUS will yield an errorlevel of 0 if all operations succeeded or
if only non-fatal errors (warnings) occurred.
If something's wrong, it will pass on the errorlevel returned by
the child program invoked.
If the child program could not be started, GUS will return
errorlevel 202 = no such program file found in PATH
203 = non-existing directory
204 = too many open files (increase FILES=... parameter
in your CONFIG.SYS file)
205 = access denied
206 = invalid handle
208 = not enough memory to start the child program
210 = invalid environment
211 = invalid format
218 = no more files
If the child program could be started but something else is wrong,
GUS will return
errorlevel 1 = for all errors not reported in the list below
220 = no such (mail) directory
221 = no such file(s)
222 = the last archive file handled is bad or of
a type unknown to GUS and the unpacker program
(if at all started) returned an errorlevel of 0
255 = bad configuration data appended to GUS.EXE

Note, that GUS will not be able to search the PATH environment
variable after the 255th character, if your PATH should be that long.


3.2. Unpacking Mailarchives
~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you are a BBS SysOp or a Point connected to a Fidonet Technology
compatible electronic mail network, you receive mail packets
compressed and bundled within mailarchives. You obviously need to
unpack those mailarchives.
You can do that in two ways:

) Have your mailprocessor call GUS to unpack the mailarchives.

+ If your mailprocessor allows you to specify which unpacker it
should invoke to decompress mailarchives, have it call GUS.
Example for ConfMail:
> CM IMPORT AREAS.BBS -K -N -F Conf.Imp -A GUS
This approach has the disadvantage that GUS will create any
directories embedded in the archive, should these not exist.
Another disadvantage is, that the mailprocessor is still in memory.
This occupies a lot more memory than is necessary.

+ If your mailprocessor does not allow you to specify which
unpacker to use, it will most likely expect ARCE or PKXARC/
PKUNPAK. Rename GUS.EXE to ARCE.COM or PKXARC.EXE or
PKUNPAK.EXE, whatever your mailprocessor wants.
If your mailprocessor wants to use an unpacker that needs a
specific decompress command (like PAK E Archive), you cannot
have it call GUS, since GUS would interpret its first
command-line argument as the archive name.
Use the method described in the next paragraph to have GUS
unpack your mailarchives BEFORE your mailprocessor is started.
Since your mailprocessor will only see mail packets then and no
mailarchives, there will be no problem.

) Have GUS unpack all mailarchives BEFORE you invoke your
mailprocessor.
--> This is the preferred method. <--
You do this by starting GUS with the following command-line:

GUS Inbound_directory /M

Instead of the archive name, you specify the path to the
directory where your inbound mail is located.
Suppose your inbound directory is D:\Opus\NetFiles. GUS will
unpack all mailarchives in that directory with the following
command:
> GUS D:\OPUS\NETFILES /M

After a mailarchive has been unpacked succesfully, GUS will
delete it automatically.
If a mailarchive cannot be unpacked succesfully, then GUS will
create a subdirectory BADARC.GUS in your inbound directory and
move that mailarchive to it. This allows you to inspect the
problematic mailarchives later on while retaining their original
name. Other unpack shells always rename a faulty archive to
BADARC.001, which makes it very difficult if you would like to
restore the archive to its original name after you have
inspected and maybe repaired it. I didn't like that procedure,
so I decided to let GUS move problematic archives to a special
subdirectory instead. Let me know how you feel.


3.3. Identifying Archive Types
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
With the /I switch, you can have GUS simply report which archive
type is at hand and do nothing else.
This switch can be used just to get a list of archive types, like
this:
> GUS J:\Outbound\*.MO? /I

Type Archive Filename
---- ----------------
LZH J:\OUTBOUND\0009FE64.MO1
??? J:\OUTBOUND\8FDCB1E2.MO1
ZIP J:\OUTBOUND\8FDCB243.MO0
ARJ J:\OUTBOUND\FF24FFE9.MO0
LZH J:\OUTBOUND\8FDCB241.MO0

GUS yields something like the above list. The '???' means that GUS
was unable to determine the archive type, possibly because it isn't
an archive at all. In this case, it was a zero-length file.

A much more useful way of using this switch is to determine the
type of just one archive and act upon that. For instance, to add a
file to any archive that comes along.

If used with /I, GUS will return an errorlevel from 0 to 15,
indicating the archive type.

Archive Type: Unknown ARC ARC+ ARJ DWC HA HAP HPK HYP LZH PAK
Errorlevel : 0 1 2 3 4 5 6 7 8 9 10
Archive Type: RAR SQZ UC2 ZIP ZOO
Errorlevel : 11 12 13 14 15

ATTENTION! These errorlevels will be returned ONLY if /I is used and
~~~~~~~~~~ NO OTHER values are possible then.

Example: suppose you want to add a header text LOGO.TXT to ZIP and
ARJ files, and leave other archive types alone.
These batchfile instructions will take care of that:

GUS %1 /I
if not errorlevel 15 if errorlevel 14 goto IsZIP
if not errorlevel 4 if errorlevel 3 goto IsARJ
goto Finish
:IsZIP
PKZIP -z %1 goto Finish
:IsARJ
ARJ c -zLOGO.TXT %1
:Finish

Please be advised that the errorlevel codes assigned to each archive
type may change! If a new archive type is added to GUS, its extension
will be merged into the list shown above so that the order of the
extensions is alphabetical. If you don't like this and would rather see
new types simply be added to the end of the list, let me know. I will
comply with your wishes if enough people feel like that.
At this time, I like to have an alphabetical list and so do most of the
people I asked about this.



4. BUILT-IN DEFINITIONS


4.1. Built-In Child Program Definitions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following child programs are defined by default within GUS.EXE:

] Virus Scanner/Detector

Program Options

SCAN .EXE. /NOMEM

This is the program from McAfee, Inc. The options direct it to scan
the current directory only (which will be the target directory in
which the archive was unpacked by the time the detector is called),
but not to scan the computer's memory for viruses.

] Archive Unpackers

TypeProgram ExtractReplaceDisplayTest View Path Password

ARC PKUNPAK .EXE-n -r -c -t -v *****g
A7+ XARC .EXE /o ***** ***************/g
ARJ ARJ .EXEe -uy e -y p t l DWC DWC .EXExow xw p t v r g
HA HA .EXEet ety ***** t l HAP PAH .EXEe e ***** **** l **********
HPK HPACK .EXEx -on x -oa p t v -da -c
HYP HYPER .EXE-x -xo ***** *****-v p *****
LZH LHA .EXEe /m+ e /m+c+p /m+ t /m+l x+ *****
PAK PAK .EXEe/WO e/WA p t l /PATH/g=
RAR UNRAR .EXEe -o- e -o+ p t l SQZ SQZ .EXEe /o0 e /o1 p t l UC2 UC .EXEE E -F $PRF T V -S *****
ZIP PKUNZIP .EXE-n -o -c -t -v -d -s
ZOO ZOO .EXEe:O e:OS e:p e:N lC // *****

3 12 10 10 10 10 10 5 5

The numbers above indicate the number of characters provided for
each string.

Note that Extract, Replace, Display, Test and View are COMMANDS,
while Path and Password are OPTIONS. The difference is, that an
OPTION is always combined with a COMMAND and cannot be used alone.
If the first character of the Path option is a `<', however, it means
that the second character should be used to replace the first command
string character. This is, for instance, the case with ARJ, HA, RAR and
SQZ, who all need the `e' command to be replaced with `x' in order to
extract files while using embedded path information.

All spaces means that that particular program does not need any
parameters for that particular command.

All stars means that that particular program does not support that
command or that option.

NOTE: the $PRF command for the UC rev. 2 archiver will actually print
files to the printer and not to StdOut as we would like to have it.
The solution is easy enough, though. UC.EXE will call a batchfile
U2_PRINT.BAT to actually do the printing. Rename the current
batchfile to *.OLD and create a new U2_PRINT.BAT containing only
the following three lines:

@echo off
echo.
type %1

That's all! (Notice no space between `echo' and `.' in the second
line.) Now the output will go to StdOut.

ATTENTION! When encountering an ARC sfx made by SEA's MKSARC program,
GUS will identify it correctly, but PKUNPAK can't handle this sfx and
will therefore exit with an error. If you expect to handle a lot of
MKSARC sfx files, then you'd better replace PKUNPAK by ARC 6.02 in
GUS' configuration segment.

You may want to redefine some of those built-in definitions for
various reasons. To use another unpacker program, for instance.
Or to change some parameters.


4.2. How To Define Other Unpackers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There are two ways to modify the built-in definitions.

You can grab a hex editor and change GUS.EXE directly. (The unpacker
definitions were appended to GUS.EXE, so you'll find them at the end
of the file.)
If you do, please take note of the lengths of the strings as listed
above in section 4.1. All strings occupy the specified number of
characters. To achieve that, they were padded with spaces where
necessary. When you edit them, make sure you retain the number of
characters and do NOT change the funny looking character at the start
of each string (that's in fact the string length indicator byte).
If a particular parameter is not supported by a certain unpacker
program, then you should edit the appropriate field to contain all
stars.

If you own a Turbo Pascal compiler v5.0 or later from Borland
International, you can edit the file GUS_WCFG.PAS and re-compile it.
This small program will update the configuration information at the
end of GUS.EXE for you. Do *NOT* modify the record layout of that
information, since GUS will not recognize it anymore if you do.

Future versions of GUS may come with a complete setup program to
edit and save a new configuration, or have a text configuration file.
I haven't decided yet which way to go. If you have any comments on
the subject, I would be glad to hear them. Please write to me via
email or any other means.



5. GUS & OTHER SHELLS


Since GUS was first created, other authors have joined the club and
released their own versions of a utility that identifies archive
types and shells out to the appropriate unpacker programs.

Some of those other shell programs come with source, others don't.
Some have configuration files, others don't.
Some are large, others small.
Only one is GUS and all the others "ain't"! ๐Ÿ™‚

Why should you use GUS?


1. GUS is small and fast. Other shell programs typically use a lot
more memory than GUS does.
2. GUS provides you with all possible commands to allow not only
automatic use, but also easy DOS command-line usage.
3. While scanning a file to determine the archive type, the
identification bytes have to be investigated in a well-defined
order. Only then, the program will not be fooled by things like
archives within archives.
GUS is the only program that does this flawlessly: it will never
be fooled.
4. GUS has built-in code especially designed for archives that have
their identification code at the end of the file. If such an
archive has been transmitted by means of a protocol like
X-modem, some junk may have been appended to the file to make it
grow to the next 128 byte or even 1 K-byte boundary!
GUS is the *only* program that will recognize an archive with
appended junk because it can skip that while scanning.
(At this time, this is only needed for DWC archives, but you
never know...)
5. The HAP&PAH, HPack and DWC archivers require their compressed files
to have the respective extension '.HAP', 'HPK' and '.DWC' or else
they won't work with them. GUS knows this and will rename any such
archive that does not have the proper extension before calling
the dearchiver program and rename it back to the original name
afterwards.
(Well, actually, HPack 0.79 and higher have an option which
will allow you to use another extension but since the renaming
code was already in GUS for the previous version of HPack, I
decided not to use this option.)
6. Because *I* wrote it!



6. HOW GUS IDENTIFIES ARCHIVES


GUS recognizes archives by searching for well-defined patterns in the
archive file. Such a pattern can be from 1 to 7 bytes in length and
it is extremely important that they be checked in the PROPER ORDER!
That is what distinguishes GUS from all it's competitors: most
programs do search for the right patterns (with the exception of the
pattern for ZOO, which is almost always wrong), but don't do this in
the proper order. That can result in faulty identifications,
specifically when encountering nested archives (archives within
archives).

6.1. Recognition patterns as used by GUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ArcType Offset Pattern Comment
------- ------ ------------ -------------------------------
ARC 0 0x1A
ARC+ 0 0x1A Method byte (offset 1) of all
PAK entries needs to be scanned: if
HYP >= 0x0A then PAK;
>= 0x48 then HYP;
== 0x14 then ARC+
Note: PAK can also be recognized
by locating the byte 0xFE at offset
EOF-2, but GUS doesn't use that
because it is less accurate than
scanning the method bytes, which
has to be done anyway for identi-
fying ARC+ and HYP.
For completeness, the record layout
of an ARC archive will be given in
paragraph 6.2.
ARJ 0 0x60 0xEA
HA 0 'HA' Offset 4 binary ANDed with 0xFC should
yield 0x20. This is an additional check
that GUS performs.
DWC -3 'DWC' Offset -3 means the third LAST byte
of the archive file.
It is possible that some junk is
present at the end of an archive,
because of Xmodem transmissions for
example.
In order to avoid GUS not recognizing
the archive because of this, the last
1028 bytes (or 343 triplets) are read
into a buffer and if that buffer
contains the string 'DWC', then we
have a DWC archive.
An additional check will be done,
however. The `DWC' string will have
to be the last item in a 27 byte
structure of which the first two
items are ArcStrucSize=27 (word size:
2 bytes) and DirStrucSize=34 (byte
size) before GUS will accept the file
to be a DWC archive.
LZH 2 '-l??-' The '?' specifies a wildcard
character.
HAP 0 0x91 '3HF'
HPK 0 'HPAK'
UC2 0 'UC2' 0x1A
ZIP 0 'PK' 0x03 0x04
ZOO 20 0xDC 0xA7 0xC4 0xFD
Most other programs search for the
string 'ZOO' at the front of the
archive, but that is wrong! Only
the ZOO archives made using Rahul
Dhesi's program would be recognized
this way. ZOO archives made by an
Amiga or a computer running Unix
would not necessarily be recognized!
SQZ 0 'HLSQZ'
RAR 0 'Rar!' 0x1A 0x07 0x00


6.2. Record layout of ARC/ARC+/PAK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The record which describes each archive entry:
.--------------------------------------------------.
|var |
| ArcHeader : record |
| Marker: Byte; |
| Method: Byte; |
| Name : array [1..13] of char; |
| Size : DWord; |
| Stamp : DWord; |
| CRC : Word; |
| Length: DWord; |
| end; |
`--------------------------------------------------'

Procedure to scan all archive entries:
.--------------------------------------------------.
|begin |
| seek(F, 0); |
| Done := false; |
| YieldARC := ARC; |
| repeat |
| {$I-} |
| blockread(F, ArcHeader, sizeof(ArcHeader)); |
| {$I+} |
| if IOresult = 0 |
| then begin |
| if ArcHeader.Method >= PAKid |
| then begin |
| Done := true; |
| YieldARC := PAK; |
| if ArcHeader.Method >= HYPid |
| then YieldARC := HYP |
| else if ArcHeader.Method = ARPid|
| then YieldARC := ARp |
| end |
| else MoveFilePtr(F, ArcHeader.Size); |
| end |
| else Done := true |
| until Done |
|end; |
`--------------------------------------------------'

This is of course all in Turbo Pascal, the language in which GUS was
written. The above are in fact literal excerpts from GUS's source
code.


6.3. How GUS identifies SFX (self-extracting) archives
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The basic principle is simple. A self-extracting archive consists of an
extraction program in EXE form followed by the archive itself as
appended data.
The header of an EXE file contains information to determine the size of
the EXE portion of the file and hence the offset where the appended data
starts.
This proved to be true for all archive types, except for SFXs made by
MKSARC, the ZIP/sfx as used in PKLTE115.EXE and the ZIP/sfx for OS/2.
GUS has those offset values hardcoded.
Should you encounter other self-extracting archive types which GUS
doesn't recognize, please let me know. Don't forget to mention,
however, by which program those self-extractors were made.


6.4. Mandatory order for scanning recognition patterns
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 - RAR
2 - SQZ
3 - ZIP
4 - HPK
5 - UC2
6 - HAP
7 - ZOO
8 - LZH
9 - HA
10 - ARJ
11 - DWC
12 - ARC/ARC+/PAK/HYP

This order is mandatory because it guarantees the greatest chance
for a correct recognition.
Every other order would increase the chance for a faulty result.
This is also the reason why the archive specifications are still
built into GUS and not given in a seperate configuration file
(like the one used by Jeffrey Nonken's PolyXarc, for example):
I still haven't found a good method to have GUS determine auto-
matically in which order the patterns have to be scanned, if a
possibility exists that new patterns would be added to the list.
I can't expect the users to include new patterns in the proper
order themselves, can I? Therefore, I don't think providing GUS
with a CFG file is very important at this time. I see no problem
for providing a new GUS when a new and exciting archiver is
released.

That's it folks! If you're curious: the Borland Pascal source for
GUS is about 1100 lines in length. Those lines are `filled' in the
same way as those of the procedure quoted above.

*** NOTE: you may use the scanning and identification method as
used by GUS and as described above in your own programs, but
please be so kind and don't forget the reference indicating where
you got the information!



7. RUNTIME MESSAGES


GUS may produce a number of messages while it's working.
I will list all messages below, with an explanation what's wrong.

[A] General information messages
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MESSAGE: Child program returns exit code #
-> this message is given when the invoked unpacker program returns
control to GUS. It shows the errorlevel returned by the
unpacker program. The "#" will be replaced by the actual
exit code.

[CHILD]: unpacker_commandline
-> this is shown in Quiet mode (/Q switch) instead of the
archiver's screen output. The unpacker_commandline will be
replaced by just that.

Extract: ALL files (XARC cannot extract specific files)
-> this message is shown when the first four characters of the
unpacker program definition string are "XARC". Any files to
extract specified on the command-line will be ignored.


[B] Warning messages (non-fatal errors)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WARNING: multiple target directories defined -- will use the LAST one!
-> you have defined more than one target path on the command-line.
GUS warns you that it will ignore all paths but the last.

WARNING: you need to use /D (capital!) to have the unpacked archive
deleted.
-> you have specified "/d" in lower case. For security reasons, GUS
will only accept a capital D for the Delete switch.
The unpacked archive will not be deleted.

WARNING: unknown switch /X ignored
-> you have specified a switch that GUS doesn't know. In the above
warning message, the "X" will be replaced by the actual
character (converted to upper case) that you used.
GUS will continue but ignores this unknown switch.

WARNING: a slash by itself is not a valid option -- ignored
-> you have typed a slash "/" followed by a space or an end-of-line.
GUS will continue and ignore this.

WARNING: unknown parameter #9 X ignored
-> you have typed something on the command-line that GUS can't
decipher. The actual word you typed will be inserted instead of
"X" in the above message, and the number of that parameter on
the commandline will be shown instead of the "9" above.

WARNING: can't open NUL device -- Quiet command ignored
-> this occurs most often if the /Q (Quiet) command is used and when
one or more TSRs were loaded with their output redirected to NUL.
This yields a DOS sharing violation error, hence this message from
GUS.

WARNING: unable to determine archive type due to error
while opening file
-> for some reason, GUS can't open the file it has to investigate.
Bummer! GUS will simply skip it and continue with the next one, if
any.

WARNING: XXXXXXXXX.XXX suddenly disappeared!
-> GUS was working with an archive file which suddenly vanished.
Perhaps you're using a multitask or multiuser system and another
task deleted or moved the file? Anyway, GUS will report it and
try to continue working as best as it can.

WARNING: cannot create new filename for rename or move! (Disk full?)
-> while trying to rename (like when an archiver needs a fixed
extension) or move (like when a mailarchive couldn't be
unpacked) a file, GUS increments the filename (in case of a
fixed extension) or the extension (in case of a bad archive)
when it at first doesn't succeed with the rename or move.
If the filename or extension cannot be incremented anymore and
no other options are left, GUS issues the above error message.

WARNING: cannot erase incomplete target XXXXXXXX.XXX
WARNING: cannot erase original after successful copy XXXXXXXX.XXX
-> these warnings can occur when GUS was trying to move a file
(normally a bad archive) to another drive, when the file has to
be physically copied and after successful completion deleted.
If something goes wrong during a physical copy, GUS will abort
the copy and delete the incomplete target. If that isn't
possible, the first warning is issued.
If the copy was successful, GUS will delete the original file so
only the identical target will remain. If the original cannot be
deleted for whatever reason, GUS will issue the second warning.

WARNING: moving bad archive HHHHHHHH.XXX to d:\badarcdir\
-> in mail unpack mode (/M switch), GUS was unable to unpack an
archive and warns you that it will be moved to the BADARC.GUS
subdirectory that GUS creates in the mail inbound directory, or
to the directory specified by the /B switch.
This warning will also be shown without in normal mode, but only
if /B was used.
The actual name of the bad archive will be inserted in the
message instead of "HHHHHHHH.XXX" and "d:\badarcdir" will be
replaced by the path to the default or specified bad archive
directory.

WARNING: cannot erase unpacked archive!
-> in mail unpack mode (/M switch) or if the Delete option (/D switch)
was used, GUS is unable to delete the archive after it has been
unpacked successfully.
This more than likely means that the archive was marked
Read/Only. You will have to unlock and delete it manually.
As mailarchives are created fresh upon receipt, it is very
unlikely that they would be marked R/O.

WARNING: unsupported command -- will do normal extract instead
-> you tried to perform an action not supported by the particular
archiver defined within GUS (i.e., issue a /T [test] command
with the HYPER archiver program).
GUS warns you it will ignore that command and do a normal
extract instead.

WARNING: XXX type cannot be unpacked into embedded directories!
-> the unpacker program has no option to enable using embedded
directories or creating them, so all unpacking will be done
into the current directory, since that is the only way.

WARNING: XXX type cannot be garbled - ignoring password...
-> you supplied an extraction password for an archive whose
unpacker program does not support password-protection.
GUS will continue the command while ignoring the /G switch.
The "XXX" will be replaced by the actual archive type detected.

WARNING: the password option cannot contain a `<' character - IGNORED.
-> this warning message is of course not possible when using GUS
from the DOS commandline, since DOS will interpret all `<`, '>'
and '|' symbols first, providing GUS with arguments not
containing those symbols.
If GUS is called from another program, it is of course possible
to include this type of illicit symbols in various commands or
options. If you do, this warning will be given.

WARNING: can't rename fixed extension back to original, leaving as is...
-> GUS had to rename an archive to a name with the fixed extension
required by archivers like DWC, HAP&PAH or HPACK and now it can't
rename the file back to the original name. This can normally only
happen in a multitasking environment, for instance when the archive
file was renamed, moved or deleted before GUS could rename it back.
GUS issues this error message and leaves the file as it was.

WARNING: switching to ARC type program for directory of A7+ archive
-> if the program XARC is configured for handling A7+, GUS will
switch to the archiver program configured for the ARC type for
viewing the archive contents (directory), since XARC has no
command to do it and both PKUNPAK and SEA's ARC 6.02 will list
the directory of an ARC+ archive just fine.

WARNING: error locating directory XXX
will unpack in current directory.
-> You specified a target directory GUS was unable to find. The
target path specification will be ignored and the unpacking will
be done in the current directory.

WARNING: XXX is no archive file or a type unkown to GUS!
-> GUS encountered a file that is not one of the known archive
types. GUS will continue with the next file, if there is one.
"XXX" will be replaced by the actual archive name.
GUS will not abort, but if this was the LAST archive processed
then it will return errorlevel 222.


[C] Fatal error messages
~~~~~~~~~~~~~~~~~~~~~~~~
>ERROR<: cannot read configuration information!
MESSAGE: aborting with exit code 255...
-> GUS complains it can't find the configuration information at the
bottom of its EXE file. This means something is terribly wrong
with that EXE file. You better delete it and get the original
release archive unpacked again! (You *did* save that one,
didn't you?)

>ERROR<: DOS couldn't execute XXX due to: YYY
-> GUS was unable to load and execute the specified child program.
The path and name of that child program will be inserted in the
error message instead of "XXX" and the reason will be shown
instead of "YYY". That reason will be one of 9 possible
problems described in section 3.1. "General Usage under DOS",
EXIT CODES. If the error code returned by DOS should be unknown
to GUS, it will display "DOS ERROR" followed by the error number
instead.

>ERROR<: no such file(s)!
-> GUS was started with an archive filename specification, but no
such file could be found. GUS will abort with errorlevel 221.

>ERROR<: no such mail directory!
-> you specified a mail inbound directory (/M switch) that GUS was
unable to locate. GUS will end with errorlevel 220.



8. ACKNOWLEDGEMENTS


+ PKUNPAK FAST! Archive Extract Utility Version 3.61 08-02-88
Copyright (c) 1986-1988 PKWARE Inc. All Rights Reserved.

+ PKUNZIP (R) FAST! Extract Utility Version 2.04g 02-01-93
Copr. 1989-1993 PKWARE Inc. All Rights Reserved. Shareware Version
PKUNZIP Reg. U.S. Pat. and Tm. Off.

+ XARC - to decompress a standard ARC Format Archive, Ver 7.1,
October, 1990
Copyright 1990 by System Enhancement Associates, Inc.;
ALL RIGHTS RESERVED

+ ARJ 2.41 Copyright (c) 1990-93 Robert K Jung. Jun 03 1993
All Rights Reserved. U.S. Patent No. 5,140,321 and patent pending.

+ DWC - Archive utility, Release 5.10, Created 3/07/90
(C) Copyright 1986-90 by Dean W. Cooper; All rights reserved.

+ HA 0.999 Copyright (c) 1995 Harri Hirvola

+ Hamarsoft (R) Hap&Pah TM 3.00
Copyright (C) 1992 By Harald Feldmann.
Publicly Distributed evaluation copy.

+ HPACK - The multi-system archiver Version 0.78a0 (shareware version)
For Amiga, Archimedes, Macintosh, MSDOS, OS/2, and UNIX
Copyright (c) Peter Gutmann 1989 - 1992. Release date: 1 Sept 1992

+ Hyper - Pack Utility 2.5
Copyright (c) 1989,1990 P. Sawatzki and K.P. Nischke

+ LHA version 2.55b Copyright (c) Haruyasu Yoshizaki, 1988-92

+ Pak 2.51 Copyright 1988-90 NoGate Consulting

+ RAR 1.52 Copyright (c) 1993-94 Eugene Roshal 17 August 1994
Registered to Johan Zwiekhorst

+ SQZ -- Squeeze It(1.08.3), Jan 24 1993, Copyright J I Hammarberg

+ UltraCompressor II (tm) revision 2
"The new way of archiving."
-NL "Fast, reliable and superior compression."

(C) Copyright 1994, Ad Infinitum Programs,
all rights reserved

+ Zoo archiver, Version 2.10 (1991/07/09 02:10:34)
(C) Copyright 1991 Rahul Dhesi -- Noncommercial use permitted

+ ARCE Copyright (c) 1986-92 Vernon D. Buerg.
Extract ARC files, Version 4.1a, 4/12/92. All rights reserved.

+ Conference Mail - Revision: 4.07 by Bob Hartman, FidoNet Node 132/101
(C) Copyright 1986, 1987 by Spark Software Inc. All rights reserved.

+





Keyboard driver U.S. International

Copyright (C) 1994 and written by
Johan Zwiekhorst
ALLRIGHTSRESERVED

version 2.02

KEYBoard driver U.S. International (KEYBUI)
will allow you to type accented characters,
draw text graphic characters, blank your
screen and more! All this in a very easy way
and with a standard U.S. QWERTY keyboard.
Takes only 1.5K while resident.

+ Scan V.2.1.0 Copyright (c) McAfee, Inc. 1994. All rights reserved.



9. REVISION HISTORY


Ver. Comment
~~~~ ~~~~~~~
--> 2.00 [will be released in a few months, probably mid 1995]
or should I call it GUS'95 and keep pushing back the
release date each few months? ๐Ÿ™‚
= Please write to me and let me know what new features you would
like to see in GUS. Ideas so far:
+ archiver output in a pop-up window;
+ a full-screen version of GUS with nice colours;
+ interactive full-screen GUS with pull-down menues
(this would make it a direct competitor for SHEZ, but I'm
not sure if I want to devote my time to this since I think
SHEZ is very good);
+ OS/2 version;
+ Win/NT or Win32 version - if people want it. So far, no
requests for this.
= So let me know what you think!

1.95 [15-Mar-1995]
! This is the _LAST_ version that will run on Intel 8088 or
8086 CPUs! For all versions hereafter, you will need at
least a NEC V20 or Intel 80188 (or equivalent) CPU.
+ Some people want to redirect GUS' output to a logfile and
have asked me to provide for a more modest title screen for
GUS. So here it is. In case of redirection, the big header
will remain on screen while a small one is written to the
target device or file.
* New: people who register will now receive a "personalized"
version of GUS.
* New: /S will invoke a virus detector in order to scan
the freshly unpacked files for viruses.
* New: /Bdir will move bad or unknown archives to the specified
directory. Attention! Files resulting from an abrupted unpack
will not be deleted by GUS.
Thanks to Vic Bates (2:250/143.16) for his suggestions.
! GUS will from now on be released in another archive format.
I used LZH thusfar because it is cheap (as in free) and has a
very good compression. Unfortunately, it doesn't have
authenticity verification. So I waited until another archiver
appeared on the scene which would compress better than LHA,
have authenticity verification and a FREE unpack program.
RAR meets these requirements. Therefore, GUS will from now on
be released in a self-extracting RAR archive with authenticity
verification and archive lock enabled. Any tampering with the
archive will remove the authenticity OK message.
The self-extraction code will of course make the archive file
size larger than it should be, but since RAR is a very new
archiver I didn't want to assume everyone would have the
UNRAR.EXE or RAR.EXE programs in their possession. If RAR
becomes as widespread as ZIP or LZH, I will release future
versions of GUS in a non-sfx RAR archive.

1.91 [05-Oct-1994]
- While unpacking mailarchives, GUS would return errorlevel 0 if
the archive type could not be detected or if there was
something else wrong and the unpacker program didn't report
it. This could cause the mailprocessor to delete an
unprocessed file. Fixed. GUS will now return errorlevel 222 if
the _last_ file encountered could not be handled properly.
If GUS is dealing with mailarchives (/M switch), unknown types
will be handled the same as bad mailarchives and thus moved to
the special BADARC.GUS subdirectory.
Thanks to Gerard van der Land (2:2802/110) for pointing this
out to me.
+ Changed several messages from '>ERROR<' to 'WARNING' since
they don't cause GUS to abort.
+ Changed the licence from 'freeware' to 'shareware'. Payment
for non-commercial situations is still on a more or less
voluntary basis, though.

1.90 [07-Aug-1994]
* Supported the new Russian archiver RAR.
It performs about comparable to the Dutch UC2 archiver.
* Supported some new features of UltraCompressor II revision 2.
- A system error would occur when GUS was used in an OS/2 DOS
session and needed to shell out to one of the fixed extension
archivers (DWC/HAP/HPK). That was due to a lack of stack space
for GUS. Corrected. GUS now uses a stack of 8192 bytes.

1.80 [05-Feb-1994]
* Supported the new Dutch archiver UltraCompressor II (UC2).
It performs consistently better than either PKZIP or ARJ, but HA
and HPACK are still the best compressors around (albeit very
slow).
* Added the '/V' (View archive contents) command. Originally, I
wanted to implement my own archive lister. However, since I still
don't have the exact layout for a couple of archive types, I
didn't want to keep you waiting any longer and provided the lister
by shelling out to the appropriate archiver.
+ The GUS help screen will now also be shown when the user types
GUS /?, GUS -?, GUS /h, GUS -h, GUS /H or GUS -H.
Suggested by Hans Siemons (2:512/149).
- If the drive is full (0 bytes free), GUS is unable to move
a bad mailarchive away. GUS v1.70 would check the drive space
and abort the move if less than 32 bytes would be free.
32 bytes is indeed what's needed to create a new directory entry,
but unfortunately this doesn't help much since DOS always needs
the size of one cluster to allocate new space.
This version of GUS will therefore check if at least the size of
one cluster (or 256 bytes for HPFS volumes) is free.
Error reported by Peter Smink (2:285/1).
- GUS file /I will yield errorlevel 221 if the file doesn't exist,
instead of errorlevel 1 reported by the previous version which was
confusing (since it could also mean GUS found an ARC archive).
Changed two errorlevels:
ERROR ErrLev v1.70 ErrLev NOW
^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^ ^^^^^^^^^^
No Such Mail Directory! 0 220
No Such File(s)! 1 221
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Problem reported by Kianusch Sayah-Karadji (2:310/3.80) and
Alex Cleynhens (2:292/500).
! Just in case you were wondering: I'm using Borlands BPwO v7.0
these days for compiling GUS. No, the sourcecode for GUS doesn't
contain any OOP. I wanted to keep GUS small and OOP has a tendency
to blow the size of EXE files to huge proportions.

1.70 [14-Apr-1993]
* Added support for the Dutch HAP archive format, which compresses
at least 10% better than PKZIP v2.04.
* Added support for the Finnish HA archiver, which beats PKZIP
v2.04 by more than 20%!
* Added the "/D" or Delete option.
* Added detection of SFX (self-extracting) archives.
GUS will recognize all EXE variants of the known archive types.
Note: GUS can't handle COM self-extractors made by LHarc 1.xx,
only the EXE sfx version.
- If the drive is full (0 bytes free), GUS is unable to move
a bad mailarchive away. It would take quite some time before
GUS would give up trying, though. Fixed: GUS will check
the drive space and abort the move if less than 32 bytes are
free. (32 bytes is what's needed to create a new directory entry.)
- If a file could not be opened for the purpose of determining
the archive type, a runtime error 103 resulted. Fixed.
Added a message: WARNING: unable to determine archive type due
to error while opening file.
- Some people experienced strange `runtime 162' errors.
Here's what happened...
GUS tried to open the NUL device and create it. Some environments
may have objected to that.
I changed the code so that the NUL device is opened for writing
only (no creation) and only if the /Q option is used, not always
like before.
This still caused some systems to yield that runtime error, so I
added an error check and disabled the Quiet mode in case the NUL
device cannot be opened. That should solve the `runtime 162'
problem once and for all...
Added a message: WARNING: can't open NUL device -- Quiet command
ignored.
(This problem appeared mostly with systems that loaded TSRs and
redirected their output to the NUL device. That causes DOS to
open but never close the NUL device, so when GUS tries to open
it, a sharing violation (runtime 162) occurs.)
Thanks to Wim Van Sebroeck, 292/862 and Bert Hubert, 2:281/506.40
for assisting me in finding a fix for this.

1.61 [21-Sep-1992]
- Fixed a bug which caused GUS to use the wrong archive name
when operating with an archiver that requires a fixed archive
extension (DWC and HPK at this time).

1.60 [20-Sep-1992]
* Added support for the HPACK archiver from Peter Gutmann, which
makes the absolutely smallest archives at this time.
* Added support for the Swedish SQZ archiver, which compresses
better than ARJ 2.30 or the new PKZIP 1.93a!
+ Previously, the first three archive types were: ARC (#1), ARJ
(#2) and ARC+ (#3). From now on, ARC+ will be #2 and ARJ #3.
This is more logical. (The reason for the previous order was
that GUS uses the abbreviation ARp internally for ARC+, and
ARp comes after ARJ alphabetically.)
- Due to a string length mismatch, GUS couldn't tell whether
UsePath or UsePassword options were supported or not. The
UsePath problem was reported by Wim Van Sebroeck (2:292/862)
and by checking that, I discovered that the same was true for
the UsePassword option. Corrected.
+ Added code to allow the Path option to replace a command
instead of being added to it. (Indicated by `<' as the first
character in the Path option in GUS_WCFG.PAS)
Only needed for ARJ and SQZ at this time. (The previously used
`e -jf' for ARJ doesn't seem to work equal to `x', so that was
changed.)
- GUS `forgot' about the specification indicating which files had
to be extracted, once an ARC+ type archive had been worked on.
Reported by Wim Van Sebroeck (2:292/862) and fixed.
- If the specified target directory ended with a backslash (\),
GUS wouldn't recognize it as the target directory. Reported by
Wim Van Sebroeck (2:292/862) and fixed.
+ Extract command for ARJ changed from `e -n' to `e -uy' and
modified some other archiver parameters in order to make the
behaviour of various archiver programs more homogenious.
GUS without /R option:
(1) XARC and HYPER will ask you if they should overwrite older
files. Unfortunately, these programs have no command
options to work in batchmode and avoid this.
(2) HPACK will never overwrite older files because it doesn't
have an option for this.
(3) all other archivers will overwrite older files and skip
the rest.
GUS with /R will cause existing files always to be
overwritten.
+ If someone would combine several real commands on the GUS
commandline, the effects might not be what one desires.
Example: GUS * /T /R would start unpacking when one would
expect it to ignore the replace command and do a test only.
So I have changed the behaviour. The /T command now has priority
over all other commands. This means that if you specify multiple
commands, the /T (test) command will be executed and all others
ignored. If you specify /P and /R, the /P has a higher priority
and will be executed. The /R will be ignored. The priority of a
command increases if it can do less damage. So the priority order
for the GUS commands is in descending order: /I /T /P /R
(remember: the other switches are options, not commands!).
This problem was discovered after a tip by Alex Cleynhens
(2:292/500).
+ Additional check for DWC archives. Apart from the string `DWC'
in the last 1K of the file, it is now required that this string
is the last item in a 27 byte structure for the file to be
identified as a DWC archive.
- GUS reported a runtime error when trying to rename an archive to
a fixed extension and if the new name existed already. Reported
by Wim Van Sebroeck (2:292/862). Fixed: the name is now
incremented. Modified the routine which moves bad mailarchives
to the BADARC.GUS subdirectory as well: if a file with the
same name already exists in the BADARC.GUS subdirectory, the
extension of the file to be moved is incremented.
- GUS had a problem if the target directory was a root directory.
In that case, it specified only the drive instead of the root
directory. Reported by Wim Van Sebroeck (2:292/862). Fixed.
- HPACK seems to require that its archives have a fixed extension
of .HPK (like DWC does). GUS directory /M /T doesn't move bad
archives into the BAD_ARC.GUS directory. Reported by Peter Smink
(2:285/1). Fixed.
! Various changes to the documentation.

1.50 [15-Feb-1992]
* Added the /N (/5) switch to prevent GUS using or creating
paths embedded within archives.
+ Made this switch automatic while working with mail archives
(/M). Thanks to John Lots (2:512/[email protected]) and Eef
Hartman (2:281/603.5) for suggesting this and detecting the
problem with this in GUS 1.40.
/N is now also automatically invoked with /P and /T.
+ Changed the way the configuration information is stored a bit,
since there was a useless amount of space being reserved for
the "Unknown" type, which of course shouldn't have been saved.
- Fixed a minor problem which caused a runtime error when
GUS.EXE was given a read/only attribute. Thanks to Rob
Essers (2:283/406.2) for reporting this.
! Cleaned up the batchfile listing in section 3.3 a bit.
Thanks to Roelof Heuvel (27:3331/[email protected]) for the
suggestion.
- Fixed a minor problem which caused GUS to not append '.*'
to a filename given without an extension when the pathame
would contain a dot somewhere. Thanks to Hans Siemons
(2:285/[email protected]) for reporting it.
- Because of a space inserted between the appropriate switch to
supply a password to an unarchiver and the actual password it-
self, encrypted archives could never be unpacked. This is now
fixed.
! Made minor modifications for PKUNZIP 2.00, due to some changes
in the way that one handles its command options.
- The `use path' option was always supplied with the ZOO unpack
commands. Corrected.

1.40 [25-Jun-1991]
+ Removed MDCD archive support again, since nobody was likely
to use it -- unless you're looking for the worst performing
archiver ever, of course.
* Added support for the new LHA version 2 archiver from Yoshi,
which succeeds LHARC. The previous version of GUS could
already handle the new compression, but I didn't expect the
name of the program to be changed.
* Added support for the ARJ archiver program from Robert K.
Jung, which yields nearly always the best compression and
has a lot of features.
* Added support for the HYPER archiver program from Germany,
which seems to outperform every other archiver on 600..800K
logfiles ONLY. Weird.
* Added support for ARCfiles made by the new ARC version 7
compressor from SEA. At this time, only one public domain
extractor is available, which unfortunately lacks almost
every feature GUS has to offer.
My thanks to Donn Bly (1:236/[email protected]) and Jeffrey
Nonken (1:273/[email protected]) for providing me with all the
information on the ARC7+ archive format and the XARC
program.
! GUS is now fully commandline compatible with Vernon Buerg's
ARCE program. All of ARCE's switches are supported - except
for /5, which prevents ARCE from creating subdirectories
contained within ARCfile entries.
* GUS provides two extra options: /I will identify an archive
type by means of the exitcode (errorlevel) and /M will
unpack and delete mailarchives in Fidonet Technology
Networks.
- BUGFIXES:
= cleaned up handling zero-length and read/only files.
From now on, GUS won't abort with a runtime error on
those.
= you could only specify one single file to extract on GUS's
commandline, although the help screen and manual suggested
you could give more than one filespec.
That's also corrected now, so you can indeed specify
multiple files.
* OTHER IMPROVEMENTS:
= the code which detects the archive type has been completely
re-written and now is a *lot* faster than before!

1.31 [1990]
! This version was never released, but mentioned in the
documentation of the ARCA*Simulator v2.31 (ASIM_231.LZH).

1.30 [1989]
! This version was never released, but mentioned in the "Latest
Software Versions" column of the FidoNews magazine.

1.20M [1989]
* Added MDCD archives, corrected an error which made GUS not
recognize uncompressed file entries in an LZH archive, made sure
the new compression method of PAK is supported, added features to
allow selection of files and target directory for unpacking.
This is a maintenance release, hence the 'M' behind the version
number.

1.10 [1989]
* Added LZH archives, and changed the way DWC archives are
identified in order to identify them even if up to 1K of rubbish
is appended to the end of a DWC archive. This is useful for DWC
archives which have been transferred by means of an Xmodem
protocol.

1.00 [1989]
! Base version. (Turbo Pascal 5.0)
_______________________________________________________________________(eof)__


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