I couldn't find '--rsyncable` in the man page. I found some references on the mailing list, and a patch in macports, but GNU gzip 1.6 on up-to-date Arch and Gentoo Linux both respond with:
gzip: unrecognized option '--rsyncable' Try `gzip --help' for more information.
It's odd because this seems very useful, and I was surprised I hadn't heard of it.
I don't know that there's any way to identify from a .gz
file the command line "speed" option that was used when it was created/compressed. If there is, I'm not seeing it in www.gnu.org/software/gzip/manual/gzip.
You'll be surprised that this has little to do with Linux and more to do with GNU project. Since their is a GNU version for most compression apps, I imagine the project/team works closely to make tar compatible.
http://en.wikipedia.org/wiki/GNU/Linux_naming_controversy http://www.gnu.org/software/tar/ http://www.gnu.org/software/gzip/