On 9/24/16, Todd Brunhoff <to...@nvr.com> wrote:
> While writing yet another backup script using tar --listed-incremental,
> I found that there was no option to prevent archiving directories that
> had no changes. I see this as a problem because when doing an
> incremental backup of a system with 10's of thousands of directories,
> yet where only a few files have changed, all of the directories are
> archived. This makes for a huge incremental backup which is excessive
> and makes it difficult to identify what actually changed.
>
> I did try some related options such as --newer-mtime=date and
> --atime-preserve={system,replace,}, but without success: all directories
> were always archived.
>
> Eventually I settled on an external solution which really ought to be in
> tar. And that is to use --files-from=- and feed it with something like
> find <path> -newermt <date>.
>
> I should note a related irritation. If the find found no files, tar
> would archive everything in the current directory. I understand that tar
> takes targets from the command line and, optionally from the
> --files-from argument, but there is no way to say to take files only
> from the --files-from argument.
>
> Thanks,
>
> ToddCould you provide full command line or a script demonstrating the issue? If you are giving full paths (starting with '/'), then you might want to try with relative paths only. I've reported a similar issue when using -C (change directory) option. I've written bugreport ( http://lists.gnu.org/archive/html/bug-tar/2016-08/msg00003.html ), but so far I haven't gotten any reply. I'm starting to think that gnu tar is unmaintained project rigged with bugs. :( Best Regards Ivan Kalvachev.
