file uncompression with native Windows Emacs

[Will Parsons]

I'm confused about what I should expect for file uncompression with
native Windows Emacs. I'm running:

GNU Emacs 25.1.1 (i686-w64-mingw32)

Curiously, if I visit a file compressed with bzip2, Emacs has no
problem opening it, but if I visit a file compressed with gzip, Emacs
complains that "Uncompression program 'gzip' not found".

How is this supposed to work? I don't see any compression binaries
packages in the Emacs installation directory, but I do have an
ezwinports directory that contains bzip2 utilities, so perhaps Emacs
is using that (but how does it know?) If ezwinports is the source of
bzip2 for Emacs, I don't see similar gzip utilities, so I'm quite
confused.

--
Will

[B. T. Raven]

ezwinports is probably in your path. Type "where bzip2.exe" to see if
this is so. A couple of gzip binaries for w32 are here:

http://www.gzip.org/ ;; put them one of them in the same directory
where bzip2 is now and emacs should find it.

It looks like you need both bzip2 and bunzip2 (and maybe
bzip2recover.exe plus a dll in case something goes wrong). gzip
decompresses with the -d switch. Since gzip is older it's probably more
reliable but I don't know much about it since I use only decompression
(usually with 7-zip).

Ed

[Will Parsons]

On Friday, 9 Dec 2016 10:10 AM -0500, B. T. Raven wrote:
> On 12/8/2016 19:29, Will Parsons wrote:
>> I'm confused about what I should expect for file uncompression with
>> native Windows Emacs. I'm running:
>>
>> GNU Emacs 25.1.1 (i686-w64-mingw32)
>>
>> Curiously, if I visit a file compressed with bzip2, Emacs has no
>> problem opening it, but if I visit a file compressed with gzip, Emacs
>> complains that "Uncompression program 'gzip' not found".
>>
>> How is this supposed to work? I don't see any compression binaries
>> packages in the Emacs installation directory, but I do have an
>> ezwinports directory that contains bzip2 utilities, so perhaps Emacs
>> is using that (but how does it know?) If ezwinports is the source of
>> bzip2 for Emacs, I don't see similar gzip utilities, so I'm quite
>> confused.
>
> ezwinports is probably in your path. Type "where bzip2.exe" to see if
> this is so. A couple of gzip binaries for w32 are here:

You're absolutely right.

> http://www.gzip.org/ ;; put them one of them in the same directory
> where bzip2 is now and emacs should find it.

I downloaded a Windows version of the gzip utilities from gnuwin32 and
put them in a directory in my PATH, and now Emacs has no difficulty
opening them. I had expected a more "official" way of handling
(de)compression, but I'm happy. Thanks!

--
Will

[Gene]

Though this may look-like or seem-like something specific, if you use GNU Emacs for Windows long enough you'll discover other problems arising from unixoid development and operational environment of Emacs.
So if you'd rather fix the problem systemically rather than piecemeal as you encounter problems you might want to consider installing Cygwin then using the package cygwin-mount to point to the repository of unixoid apps/programs/filters which emacs had available to it during it's formative years and pretty much retains to date.

Here's a snippet from my package list:
cygwin-mount 20131111.2146 installed Teach EMACS about cygwin styles and mount points

Another incidental advantage of having cygwin installed is that you can run emacs under cygwin if/when you want or need to use emacs in a Unix-like environment, for example with BASH running as a shell in a buffer.

If you DO opt to install Cygwin I recommend that you follow Steve Yagi(sp)'s advice and NOT install it in c:/cygwin, but rather directly in c:/ so the executables will end up in c:/bin/

I've encountered the same problems you have with decompression.
I've often just launched GNU emacs for cygwin from cygwin's terminal then effortlessly converted those compressed files, exited cygwin, then accessed the decompressed files via GNU emacs for Windows.