Jared B. - 2012-03-04

Agreed. I just encountered this problem as well. Most of the Linux compression-only formats preserve the original date modified timestamp across compression and decompression. This even includes the newish xz utilities. Eg.:

$ ls -l Axelay.sfc
<SNIP> 2010-12-19 16:49 Axelay.sfc

$ xz Axelay.sfc
$ ls -l Axelay.sfc.xz
<SNIP> 2010-12-19 16:49 Axelay.sfc.xz

$ unxz Axelay.sfc.xz
$ ls -l Axelay.sfc
<SNIP> 2010-12-19 16:49 Axelay.sfc

However, I prefer using p7zip for my XZ-compression needs because it's a good 50% faster (which is awesome, btw). Unfortunately, it does not preserve the timestamp of the original file:

$ ls -l Axelay.sfc
<SNIP> 2010-12-19 16:49 Axelay.sfc

$ 7z a -txz -ms=on -mx=9 -mmt=7 Axelay.sfc.xz Axelay.sfc && tp Axelay.sfc
$ ls -l Axelay.sfc.xz
<SNIP> 2012-03-04 14:29 Axelay.sfc.xz

$ 7z x Axelay.sfc.xz
$ ls -l Axelay.sfc
<SNIP> 2012-03-04 14:30 Axelay.sfc

It could be that I"m just not passing the correct options, but I've been unable to find anything about preserving dates or timestamps.

Would definitely appreciate if you could look into addressing this in a future release.

Thanks.