Updating a single file in a compressed tar

Question

Given a compressed archive file such as application.tar.gz which has a folder application/x/y/z.jar among others, I'd like to be able to take my most recent version of z.jar and update/refresh the archive with it.

Is there a way to do this other than something like the following?

tar -xzf application.tar.gz
cp ~/myupdatedfolder/z.jar application/x/y
tar -czf application application.tar.gz

I understand the -u switch in tar may be of use to avoid having to untar the whole thing, but I'm unsure how to use it exactly.

Answer 1

Well, I found the answer.

You can't use tar -u with a zipped archive. So the solution I used was the following. Note that I moved the z.jar file to a folder I created in the current directory called application/x/y for this purpose.

gzip -d application.tar.gz
tar -uf application.tar application/x/y/z.jar
gzip application.tar

When I did a tar -tf application.tar (after the update, before the gzip) it showed up properly.