On Wed, 31 Dec 2003, Cameron Simpson wrote: > RTFM. The info file for tar says: > > `--update' `-u' Adds files to the end of the archive, but only if they > are newer than their counterparts already in the archive, or if they do > not already exist in the archive. see "update". Believe me, I read this manual several times and I fully understand the above. I even reproduced exactly this behavior of tar. (See my second example in my original mail). BUT "tar -uvf home.tar ~" adds each time ALL files in ~ to home.tar - NOT only the ones which have changed or which are new. So in fact the size of home.tar is doubled with the second time I call "tar -u home.tar ~", even if just 1% of the files in ~ have changed. > This about this for a moment: tar is made to work on tapes, and you > can't arbitrarily insert/delete data on a tape. In fact you can't do > that with UNIX files either (you can overwrite stuff, but not remove > things in the middle or insert things i.e. change the lengths of stuff > in the middle of a file). And this is why the above mechanism is used. Again: I did not expect tar to remove anything from the existing home.tar - all I wanted was that it adds only the files, which have changed and not all the files. In other words: "tar -u" behaves exactly like "tar -r" - but only under certain circumstances which are not clear to me. Cheers, Ingo. -- Shrike-list mailing list Shrike-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/shrike-list
