tar stores relative paths. GNU tar even says so if you try to store an absolute path:
tar -cf foo.tar /home/foo
tar: Removing leading `/' from member names
If you need to extract a particular folder, have a look at what's in the tar file:
tar -tvf foo.tar
And note the exact filename. In the case of my
foo.tar file, I could extract
/home/foo/bar by saying:
tar -xvf foo.tar home/foo/bar # Note: no leading slash
So no, the way you posted isn't (necessarily) the correct way to do it. You have to leave out the leading slash. If you want to simulate absolute paths, do
cd / first and make sure you're the superuser.
There are very obvious, good reasons why
tar converts paths to relative ones. One is the ability to restore an archive in places other than its original source. The other is security. You could extract an archive, expect its files to appear in your current working directory, and instead overwrite system files (or your own work) elsewhere by mistake.
Note: if you use the
tar will archive absolute paths. So it always pays to check the contents of big archives before extracting.