diff-ing and uniq-ing directory trees

[Rustom Mody]

Hello.

I do not know if this is exactly vcs stuff but I believe that git
should be able to do it so I am asking here.

I have a number of tgz's of my home directory taken at different
points of time.  I want to merge them.

I guess that I could write a little python script that does a walk or
'find .' on the directory trees collects SHA1s of each file and thus
isolates the commonalities and the differences.  But I am also
guessing that git can do the same thing more easily and cleanly.

Do you know whether this is possible?

Thanks

Rustom