Create a .zip file that can be opened by PKZIP 2.50 with 7-zip

Question

I need to create a .zip file that can be unzipped by a very old version of PKZIP - version 2.50. I am currently using 7-zip to try this, but I can use a different zip program so long as it has a CLI.

Using 7-zip's default settings to create a ZIP file, PKZIP 2.50 gives the error "PKZIP: (W3) Warning! requires PKZIP version 78.8 to extract: filename.ext"

Using a newer version of PKZIP is not an option.

I believe that the switch I want is the -m switch, but I've tried variations on this and none lead to a file PKZIP can deal with, for example the following:

7z a -mx=9 -mm=Deflate '/path/to/file.zip' '/path/to/file'

What command should I be running to create a backwards-compatible zip file?

Can you give us an example of the command line you're currently attempting to use? — Ƭᴇcʜιᴇ007, Feb 04 '15 at 15:38
Why not just use PKZip 2.5 to create the zip? Guaranteed compatibility. :) — Ƭᴇcʜιᴇ007, Feb 04 '15 at 15:49
I was hoping to put together something a bit more portable - the script will hopefully be running on Linux where the old PKZIP .exe won't run without mucking around in WINE or similar. Also, part of me cringes at re-deploying software last updated in 1998. — ArgumentBargument, Feb 04 '15 at 15:54
Since 7-Zip can create TAR, would that be an easier, native, format for Linux? — DrMoishe Pippik, Feb 04 '15 at 18:19

Romeo Ninov · Accepted Answer · 2015-02-04T16:57:53.067

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Try to use infozip/unzip. This software support very good old zip formats and clarifying OP answer:

# zip -v
Copyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license.
This is Zip 3.0 (July 5th 2008), by Info-ZIP.
Currently maintained by E. Gordon.  Please send bug reports to
the authors using the web page at www.info-zip.org; see README for details.

edited Feb 04 '15 at 16:57

answered Feb 04 '15 at 15:43

Romeo Ninov

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With your clarification I've added a +1 - I'm not going to accept an answer yet, in case anyone can shed any light on what exactly it is that Info-Zip does by default that 7z apparently doesn't, and whether that feature can be replicated in other zip programs. – ArgumentBargument Feb 04 '15 at 17:15
From what I know infozip keep working with original pkzip (from the time of DOS). And seems like 7-zip try to follow contemporary zip formats, used in pkzip now. As pkzip is not opensource 7-zip can support only public descriptions and documents – Romeo Ninov Feb 04 '15 at 17:24

score 0 · Answer 2 · answered Feb 04 '15 at 16:08

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It might not be totally portable, but I've just discovered that the default Linux zip program (tested in Mint 17.1) does create a .zip file that PKZIP 2.5 sees as valid. While I'd still like to know how to do this in a portable tool like 7-zip, this does solve the problem I have right now.

answered Feb 04 '15 at 16:08

ArgumentBargument

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ArgumentBargument, have you check what is exactly linux zip utility. It is infozip. So I do not deserve these negative points: zip -v Copyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license. This is Zip 3.0 (July 5th 2008), by Info-ZIP. – Romeo Ninov Feb 04 '15 at 16:54

score -2 · Answer 3 · answered Sep 11 '17 at 22:44

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I belive that using the Gzip command in 7zip will create a "zip" compatible archive, but I'm too lazy to test :o but I'm seldom wrong ;)

answered Sep 11 '17 at 22:44

King

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Create a .zip file that can be opened by PKZIP 2.50 with 7-zip

3 Answers3