Re: gnu tar w/ --listed-incremental --files-from

[Stepan Kasal]

Hello,

On Wed, Jan 29, 2003 at 01:33:54PM +0100, Miek Gieben wrote:
> well, what I gather from your words here, is that incremental backups with tar
> are sort of broken?

I wouldn't say that.  They work if you use them the usual way.

The boundaries of what works and what doesn't are somewhat fuzzy, though.

It might be useful to try to determine the boundaries.  For example we could
say that the list of ``given files'' may not contain any regular file, if
tar is making an incremental backup.  The manual would say this and the
program would require this.
Or, alternatively, it could be fixed that regular files work.

But I see no need to rip off the incremental stuff altogether.
It can be very useful.  Consider:

tar cjf incr$date.tar.bz2 --listed-incremental=/var/adm/home.list /home

It works.  Just rm /var/adm/home.list and run it.  Full backup is created.
Next day run in again (/var/adm/home.list is still there): an incremental
backup is made.
(I have never used it, but I beleive it works.)

> 2) fix the incremental code. This would mean ripping out --incremental and

I'm afraid you cannot rip off --incremental now.  Backward compatibility...
The maintainer (Paul) is to decide this, though.

> totally rewritting --listed-incremental

Maybe.  I haven't examined the code enough to be sure about this.

> tar --listed-incremental <file-with-only-a-date>

I'm not sure what ``<file-with-only-a-date>'' mean but I beleive
--listed-incremental should get either an empty (or better: non-existing)
file, or a file created by --listed-incremental during a previous run of tar.

Anyway:
tar --listed-incremental=<empty file>  --files-from <another empty file> 
> will tar the current directory instead of complaining with: Cowardly refusing
> to create an empty archive. This is due to the addname (".") in incremen.c

and it surely is a bug which should be fixed.  I don't have time for it atm,
sorry.  Write a patch, if you have time, and post it to address@hidden .
If you don't have time, post a bug report, so that it gets archived for Paul
and for web search machines.

Thank you for all,
        Stepan Kasal