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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?

ArgumentBargument
  • 651

3 Answers3

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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.
Romeo Ninov
  • 7,848
0

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.

ArgumentBargument
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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 ;)

King
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