Linux command/script replacing folders/directories

Question

I have the following folder setup on an ubuntu machine:
(brackets indicate folder)

[main]
   |
   |--- [old]
   |      |
   |      |--- [thequick]
   |      |           |
   |      |           |--- [aaaa] --- some files
   |      |           |--- [bbbb] --- some files
   |      |           |--- [cccc] --- some files
   |      |           |--- [dddd] --- some files
   |      |           |--- some files
   |      |
   |      |--- [brownfox]
   |      |           |
   |      |           |--- [aaaa] --- some files
   |      |           |--- [bbbb] --- some files
   |      |           |--- [cccc] --- some files
   |      |           |--- [dddd] --- some files
   |      |           |--- some files
   |      |---  ...
   |      |
   |      |--- [lazydog]
   |                  |
   |                  |--- [aaaa] --- some files
   |                  |--- [bbbb] --- some files
   |                  |--- [cccc] --- some files
   |                  |--- [dddd] --- some files
   |                  |--- some files
   |
   |--- [new]
          |
          |--- [thequick]
          |           |
          |           |--- [aaaa] --- some files
          |           |--- [bbbb] --- some files
          |           |--- some files
          |
          |--- [brownfox]
          |           |
          |           |--- [aaaa] --- some files
          |           |--- [bbbb] --- some files
          |           |--- some files
          |---  ...
          |
          |--- [lazydog]
                      |
                      |--- [aaaa] --- some files
                      |--- [bbbb] --- some files
                      |--- some files

I need to find a quick way to replace all old [aaaa] and [bbbb] folders by their respective new [aaaa] and [bbbb] folders, without affecting any other old stuff.

Answer 1

You can do:

cd /main/old
find . -type d \( -name 'aaaa' -o -name '-bbbb' \) -exec cp -RfP {} ../new/{} \;

Answer 2

This is explicit and very standard

cd main/old
for dir in `find . \( -name aaaa -o -name bbbb \) -a -type d`
do
    (
    cd ..
    if [ -d new/$dir ]
    then
        rm -rf old/$dir
        mv new/$dir old/$dir
    fi
    )
done
cd ../..