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RE: tar zxvf won't work with Redhat generated compressed tar file

> Date: Mon, 20 Apr 2015 16:38:49 -0700
> From:
> To:
> Subject: Re: tar zxvf won't work with Redhat generated compressed tar file
> On 2015-04-20, Murthy Gandikota wrote:
>>>> Then it looks like you have a DOUBLE-compressed file. That is, someone
>>>> took a .tar.gz file, and ran THAT through gzip again (which seldom does
>>>> anything except make a LARGER file - because the first round of
>>>> compression removed any redundancy). Tar cannot read a
>>>> double-compressed stream, but breaking things into two steps lets you
>>>> get back to a single compressed stream, where the tar call then
>>>> auto-decompresses because you weren't supplying an explicit 'z' the
>>>> second time around. To prove it, try:
>>>> gunzip <mytar.gz>mytar
>>>> tar zxvf mytar
>>>> and if it still untars with an explicit decompression, then you have
>>>> proven that your original file was double-compressed. Also, if I'm
>>>> right about double compression, then mytar.gz would likely be slightly
>>>> larger than mytar (rather than the usual case of the .gz being
>>>> noticeably smaller).
>>>> --
>>>> Eric Blake eblake redhat com +1-919-301-3266
>>>> Libvirt virtualization library
>>> Yes, Sir. It did untar properly. So the problem is with the
>>> server compressing during the download (I get the file from a
>>> http server)?
>>> Thanks a lot for your help
>> It would be doubly nice if cygwin handled it ;-) It seems gunzip
>> had no problem recognizing the file as double compressed.
>> Thanks all for the help.
> I think you misunderstand. Gunzip decompresses once. As Eric
> wrote, tar recognizes compressed files and will decompress them
> automatically even without specifying a compression flag such as
> 'z'. The second decompression is done by tar, not by gunzip.
> Regards,
> Gary

Got it! Thanks a ton.

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