Shell Programming and Scripting

OK, so simple question here:

Is there anyway to REMAP, while extracting with tar, specific uid's and gid's on extracted files ?

Background: The usual transfer between two servers with same literals username's names, but with different gid and uid. I would like, for example, files owned by user with uid 800 to be remapped to user with uid 900. Is that even possible in line with GNU tar ?

I would guess if this is not possible, one option would be to find those files with the specific uid and change them.

Thanks!

Hi,
You must extract your files with the destination owner.

between, you can change the uid/gid when you create your tar:

Code:

tar --numeric-owner --group=900 --owner=900 -cf file.tar file ...

Regards.

That solution only works with GNU tar.

If you are trying to extract all files from a tar archive with a given user ID (or user name) and group ID (or group name) you could use:

Code:

pax -r -ouid=UID,gid=GID -f tarfile
                     or
pax -r -ouname=USER,gname=GROUP -f tarfile

where UID and GID are the desired user and group IDs and USER and GROUP are the desired user and group names.

But, if the desire is to map several different users and/or groups in the archive to different users and/or groups as they are extracted, I don't know of any standard way to do it.

You could, however, use list mode on the archive to get a list of files with the corresponding user and group recorded in the archive, create lists of files for a given user/group, and then extract files for a given user from the archive with a specified replacement for that user/group.

If you have a BSD version of pax, you could skip the list creation step and just use -G and -U options to specify the group ID(s) or name(s) and user ID(s) or name(s) of files to be extracted on that pass (but you can still only set the user and group to one value for all files extracted on a single invocation).

Thanks for the suggestion guys.

disedorgue, yeah, I assume I could do it before. In this case, I dont have that option anymore.

Don_Cragun, those options (uid,gid,uname,gname) don't seem to work with the version of pax that came with this RHEL 6.4, which is pax 3.4 (BSD). Also, wouldn't that extract and change all of the files?

Usually only root would have the ability to change UID's and GID's like that, extract as a non root user.

Yes. I did preface the suggestion with: Then I gave you suggestions that should be available on any version of the pax utility that would allow root to extract a subset of files from an archive and change the owner and group to specified values for the files extracted on that invocation.

I should have explicitly stated that none of the given suggestions would work unless you were running with appropriate privileges as Corona688 mentioned. I assumed that you already knew that unprivileged users can't create a file owned by someone else.