[indiana-discuss] [osol-discuss] why gnu chmod in os2008.11?

[Joerg Schilling]

Tim Bray <Tim.Bray at Sun.COM> wrote:

> I've been using tar on linux since about 1996 and I've never had such  
> a failure, nor have I ever heard of anyone having one.  I'm not saying  
> that it can't happen, I'm just saying that the experience of the  
> community is that's an extremely reliable tool.

Whether your personal experiences include problems or not depends on what you 
are doing.

GNU tar did until very recently have problems with larger sparse files
and it still rejects the read back 1-5% of all continuation volumes from a
multi volume archive. Every time, I planned to reimplement an idea from 
GNU tar in star, I collected possible implementation problems and always 
found a related bug in GNU tar.

> > Roughly at the same time as GNU tar introduced -z, star introduced
> > auto-decompression. Why do you like to know about this detail if the  
> > tar
> > implementation could to this for you automagically based on the  
> > compression
> > header magic numbers?
>
> My fingers are used to typing "tar -xzf" and as long as I don't get  
> any stupid error messages and the data is unpacked, I'm happy. -T

-z is related to the outdated gzip compression.

If your archive was compressed using bzip2 or 7z, your command line fails.

Star on the other side recognizes the compression method and automagically
calls the right matching decompress program.

Jörg

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