renaming a directory and its subdirs without affecting their files

Question

I have to rename directories under the root directory with prefix "ms_PF" and then rename their subdirectories with the modified name of the main directory with an extra "_", and then copy all directories and their subs to root as follows:

root
   maindir1
   maindir2
           subdir1
           subdir2
           subdir3

maindir1 and maindir2 to be renamed with prefix "ms_PF_" and copied direct to root, because maindir2 has subdirectories they will carry the new name of maindir2 which is ms_PF_maindir2 plus and underscor (_) then all subs will be copied to root as follows:

ms_PF_maindir1
ms_PF_maindir2_subdir1
ms_PF_maindir2_subdir2
ms_PF_maindir2_subdir3

Assistance in this matter is highly appreciated. My attempted solution is something like this, but it actually needs fixing:

root_dir="/dwn/icbu_dwn/LL"
prefix="ms_PF_"
do_it () {
awk '{ print "mv $root_dir $prefix ${root_dir/\//_}" }' | sh
}
find "$root_dir" -depth -type d | do_it

Answer 1

If it is only a few directories, do it by hand (anything else will be more work in writing/debugging than in doing).

If it is a largeish set, use find(1) to create a list of the affected files, and use your favorite editor to transform that into a script doing the moving. Check it for mistakes, and fire away.

If even larger/repetitive, I'd do essentially the same as the above, but do the "edit the path into the new name" by sed(1) on-the-fly. Perhaps even called directly from find. Would make a nice one-liner to scare newbies witless...

Answer 2

This will do the renaming in the right order. Note the trailing slash in the first pattern limits the matches to directories.

cd root
for dir in maindir*/*/ maindir*; do
    echo mv $dir ms_PF_${dir/\//_}
done

outputs

mv maindir2/subdir1/ ms_PF_maindir2_subdir1/
mv maindir2/subdir2/ ms_PF_maindir2_subdir2/
mv maindir2/subdir3/ ms_PF_maindir2_subdir3/
mv maindir1 ms_PF_maindir1
mv maindir2 ms_PF_maindir2