On Tue, 2004-05-04 at 10:06, Ben Stringer wrote: > On Sun, 2004-05-02 at 03:56, WipeOut wrote: > > How does tar handle hard links?? Is there a switch to use or does it > > handle them automatically?? > > > > I looked through the man page and only saw a reference to symlinks but > > not hard links.. > > I was surprised by the answers saying tar would "efficiently" handle > hard links, so thought I would try it out. It was easy to confirm - I > used a copy of the "ls" as the contents of my first tarfile, then the > same executable and a hardlink to it in the second tar file. The 2 > tarfiles are the same size, and a verbose table of contents on the > second tarfile shows tar is aware of the link. > > Hope this is helpful to those interested. > > Cheers, Ben > > [ben@hillary hardlinktest]$ cp /bin/ls . > [ben@hillary hardlinktest]$ ls -l > total 80 > -rwxr-xr-x 1 ben ben 76188 May 4 23:58 ls > [ben@hillary hardlinktest]$ tar cf t1.tar ls > [ben@hillary hardlinktest]$ ls -l > total 164 > -rwxr-xr-x 1 ben ben 76188 May 4 23:58 ls > -rw-rw-r-- 1 ben ben 81920 May 4 23:58 t1.tar > [ben@hillary hardlinktest]$ ln ls ls2 > [ben@hillary hardlinktest]$ tar cf t2.tar ls ls2 > [ben@hillary hardlinktest]$ ls -l > total 328 > -rwxr-xr-x 2 ben ben 76188 May 4 23:58 ls > -rwxr-xr-x 2 ben ben 76188 May 4 23:58 ls2 > -rw-rw-r-- 1 ben ben 81920 May 4 23:58 t1.tar > -rw-rw-r-- 1 ben ben 81920 May 4 23:58 t2.tar > [ben@hillary hardlinktest]$ tar tvf t2.tar > -rwxr-xr-x ben/ben 76188 2004-05-04 23:58:23 ls > -rwxr-xr-x ben/ben 0 2004-05-04 23:58:23 ls2 link to ls I think the key here is the difference between hard and soft links. Hard links point to the inode (the actual file), whereas soft links point to a given name of the file (which may have more than one name or link). -- jludwig <wralphie@xxxxxxxxxxx>
