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On another (but related) note: Zip files

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  On another (but related) note: Zip files "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2017-08-30 01:00 +0200
    Re: On another (but related) note: Zip files Lck Ras <likcoras@riseup.net> - 2017-08-30 01:30 +0200
    Re: On another (but related) note: Zip files Darac Marjal <mailinglist@darac.org.uk> - 2017-08-30 12:20 +0200
      Re: On another (but related) note: Zip files Greg Wooledge <wooledg@eeg.ccf.org> - 2017-08-30 14:30 +0200
      Re: On another (but related) note: Zip files Mario Castelán Castro <marioxcc.MT@yandex.com> - 2017-08-30 16:30 +0200

#186163 — On another (but related) note: Zip files

I know that the tradition for Linux is GZipped tarballs, but I also know 
that, at least from the Gnome desktop, I can open a PKZip-compatible Zip 
file, and create a (presumably also) PKZip-compatible Zip file.

I don't, however, see a way to do so from the command line (or within a 
script) without doing an apt-get to install the zip package (and 
presumably also the unzip package).

Can somebody explain this? It seems a bit puzzling.

--
JHHL

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#186164

On 08/30/2017 07:57 AM, James H. H. Lampert wrote:
> I know that the tradition for Linux is GZipped tarballs, but I also know
> that, at least from the Gnome desktop, I can open a PKZip-compatible Zip
> file, and create a (presumably also) PKZip-compatible Zip file.
> 
> I don't, however, see a way to do so from the command line (or within a
> script) without doing an apt-get to install the zip package (and
> presumably also the unzip package).
> 
> Can somebody explain this? It seems a bit puzzling.
> 
> -- 
> JHHL
> 

File-roller, the gnome archive utility, depends on p7zip-full, which
provides support for quite a few formats. If you want to work with these
from the terminal, the pz7ip* packages provide various binaries like 7z,
7za, 7zr, and p7zip, which all do similar but slightly different things.

List of supported formats: (in p7zip-full)
 * Packing / unpacking: 7z, ZIP, GZIP, BZIP2, XZ and TAR
 * Unpacking only: APM, ARJ, CAB, CHM, CPIO, CramFS, DEB, DMG, FAT, HFS,
ISO, LZH, LZMA, LZMA2, MBR, MSI, MSLZ, NSIS, NTFS, RAR (only if non-free
p7zip-rar package is installed), RPM, SquashFS,
   UDF, VHD, WIM, XAR and Z.

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#186169

[Multipart message — attachments visible in raw view] — view raw

On Tue, Aug 29, 2017 at 03:57:52PM -0700, James H. H. Lampert wrote:
>I know that the tradition for Linux is GZipped tarballs, but I also 
>know that, at least from the Gnome desktop, I can open a 
>PKZip-compatible Zip file, and create a (presumably also) 
>PKZip-compatible Zip file.
>
>I don't, however, see a way to do so from the command line (or within 
>a script) without doing an apt-get to install the zip package (and 
>presumably also the unzip package).
>
>Can somebody explain this? It seems a bit puzzling.

I think it's down to the Freeness of the format. When PKZip was first 
released, it was shareware (meaning that the binary is provided free of 
charge, but there would be a "nag" message telling you to buy the 
product). GZip has always been free (probably GPL, but Wikipedia doesn't 
make that clear). Therefore, in the early days of Linux, gzip was the 
preferred format, because the compressor/decompressor was available for 
free.

So, because gzip has such a market share in the Linux world, it makes 
sense for it to be included in the debian base install (in fact, apt and 
various utilities rely on it, so it needs to be there). Zip files, 
though, are much less common in the Linux world. There is nothing in the 
base install of debian that requires zip files, so therefore the zip 
program is not installed.

As you point out, though, there *is* now a zip program which is Free 
(i.e which can be distributed by Debian), so access to zip files is just 
a command away.

>
>--
>JHHL
>

-- 
For more information, please reread.

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#186176

On Wed, Aug 30, 2017 at 11:14:59AM +0100, Darac Marjal wrote:
> I think it's down to the Freeness of the format. When PKZip was first
> released, it was shareware (meaning that the binary is provided free of
> charge, but there would be a "nag" message telling you to buy the product).
> GZip has always been free (probably GPL, but Wikipedia doesn't make that
> clear). Therefore, in the early days of Linux, gzip was the preferred
> format, because the compressor/decompressor was available for free.

Gzip implements the user interface and semantics of the proprietary
Unix compress(1) program, rather than the MS-DOS PKZIP program.
Where compress(1) placed a .Z extension on its compressed files, gzip
places a .gz extension.

Also noteworthy, gzip/gunzip can uncompress Unix .Z files.  It was
intended as a drop-in replacement for compress(1) and uncompress(1).

Your point about licenses is a bit off the mark.  It's about patents,
not software licenses.

compress(1) used the patented LZW compression algorithm (patent expired
in 2003), while gzip used the DEFLATE algorithm, which was also patented
(by PKWARE, no less!), but which can be "implemented readily in a manner
not covered by patents". <https://tools.ietf.org/html/rfc1951>

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#186189

[Multipart message — attachments visible in raw view] — view raw

On 30/08/17 05:14, Darac Marjal wrote:
> So, because gzip has such a market share in the Linux world, it makes
> sense for it to be included in the debian base install (in fact, apt and
> various utilities rely on it, so it needs to be there). Zip files,
> though, are much less common in the Linux world. There is nothing in the
> base install of debian that requires zip files, so therefore the zip
> program is not installed.

*GNU/Linux world*

Also it is worth noting that tar + gzip will do solid compression (it
compresses the archive as a whole), while zip compresses each file
independently. The zip approach gives worse compression, but extracting
a single file is faster, since only that file has to be uncompressed.

-- 
Do not eat animals, respect them as you respect people.
https://duckduckgo.com/?q=how+to+(become+OR+eat)+vegan

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