On 2013-11-10 Ernestas Lukoševičius wrote: > How do I create an XZ compressed archive, which could be compared by > md5? > > Right now, running "tar cJfp" creates a tarball, gives it a timestamp > and the rest is history, because the timestamp is always different > and I cannot compare such an archive... Is it possible to avoid it? > > gzip has -n, what about XZ and it's implementation on Tar?
GNU gzip has -n because by default gzip saves timestamp and other metadata to the .gz header. xz doesn't do such things. In fact xz doesn't even support metadata for now (it probably will in the future, but it won't use it by default). Probably your tar implementation creates a different .tar file on each run. E.g. GNU tar 1.27 seems to do this if using --format=pax. With --format=ustar the output doesn't vary. It is also good to keep in mind that future xz versions might create different output with the same command line options e.g. if the compression engine is updated. -- Lasse Collin | IRC: Larhzu @ IRCnet & Freenode
