OT: about compressed tarball

[Stephen Liu]

Hi folks,

I create a tarred file then compressed with bzip with following command
line;

# tar -jcpf AAA.bz2 /home/path/to/dirA

dirA is about 2G in size.

After working several days on dirA I want to create a new compressed
tarred file. Instead of repeating the above command, is there a way
starting from the old file AAA.bz2 making use of the options -u, -N,
-G, etc. to reduce the compressing time? I looked around on man tar and
Internet and could not sort out their combination on the command line.

Could you please shed me some light. TIA

B.R.
SL