If you have a complex folder structure with lots of files in each level of folders. Something like this:
/home/usr/ | |-----/folder1/ | |-----/folder2/ | | | |----file1 | |----file2 | |-----/folder3/ | |----file3 |----file4 |----/folder4/ | |-----file5 |-----file6
Well you've got the idea. If you want to delete all files from that structure but not folders. You can use find with
-type f switch.
find /home/usr/ -type f -delete
That command is going to delete only files and not folders, and you will have an empty structure to work with.