.tar.xz for snapshots?

Warren Young warren@etr-usa.com
Fri Aug 23 16:29:00 GMT 2013

Corinna, would you please consider moving to .tar.xz for snapshots?

Two reasons:

- tar preserves the executable bit.  I suspect this hasn't been a 
problem in the past since unpacking with, say, the 7-Zip GUI *does* set 
the executable bit, because of the archive flag hack.  But now that I 
have two Cygwins, I don't need the GUI.  I can wget and bzip2 -d a 
snapshot in one Cygwin and mv it into the other Cygwin's bin, so the 
difference between .bz2 and .tar.bz2 now matters.

- xz because it gives better compression than bzip2 -9 without any extra 
flags: 1.0 MiB down to 828 kiB.  By adding xz's x86 executable BCJ 
filter -- which has no equivalent in bzip2 -- it gets even smaller:

     $ tar cf - bin/cygwin1.dll | xz --x86 --lzma2 > $snapshot
     $ du -h $snapshot
     780K    $snapshot

The tar wrapper doesn't cost anything.  It makes no real difference to 
file size, and GNU tar first learned xz magic in 2009, so you can just 
'tar xf' it and expect it to do the right thing.

It doesn't hurt the 7-Zip die-hards, either.  7-Zip and xz are part of 
the same project, so of course the 7ZFM GUI can unpack a .tar.xz.

Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple

More information about the Cygwin mailing list