Best practice for merging

Hi all,

  Sorry if this sound like a noob question, but this is something that
I am still not quite happy with (and google was not of any help). What
is the best way to handle merging in between a development branch and
a release branch.
  Here is the state of my current branches:

$ git diff -w release..master | wc
 156468  688491 5327390
$ git cherry release | wc
    707    1414   30401

Should I go over all those 707 individual commit, and cherry-pick them
one-by-one ?

I know for example that I do not want to merge anything related to a
new app, eg 'app2.cxx', how would one do something like :

git merge master --not applications/app2.cxx ?

Same question, I know I want to apply any change that happen within a
subdirectory but not another (this might be a problem if a commit
contains both). Let's say I want everything but what ever happen in
directory libB, can I do:

git checkout release
git merge master
git rm -rf libs/libB

finally, If I try to apply any change directly

git checkout release
git checkout master applications/app1.cxx

This will loose the whole git history, is this a bad practice ?

Thanks a lot !
-- 
Mathieu