Copy and rename on collision

Finally I can do this with cp from GNU coreutils and its --backup flag.

cp --backup=numbered */*.txt new_directory/ 

The following command-line loop will copy the (top-level) contents of every folder named "folder*" in your current directory into a directory named "new_directory". The /* glob will, by default, not match "dot files"; use shopt -s dotglob if you want to change that behavior. If the same (base) filename already exists in new_directory, then it prefixes the destination file with the originating folder (and an underscore), in order to make it unique.

All in one line:

for f in folder*/*; do [ ! -e "new_directory/$(basename "$f")" ] && { cp "$f" new_directory/; continue; }; [ -e "new_directory/$(basename "$f")" ] && cp "$f" "new_directory/$(dirname "$f")_$(basename "$f")"; done 

Broken out for readability:

for f in folder*/* do [ ! -e "new_directory/$(basename "$f")" ] && { cp "$f" new_directory/; continue; } [ -e "new_directory/$(basename "$f")" ] && cp "$f" "new_directory/$(dirname "$f")_$(basename "$f")" done 

If you intent instead to move the files from their original locations, simply change the cp's to mv's.

Thank you @Ghilas Belhadj ! One could end up here trying to do that: copy all files from a file hierarchy to a unique directory, knowing some files may have the same name (ie: files which differ only by their absolute name):

find /dir1 -type f -exec cp "{}" --backup=numbered /dir2 \; 

But I don’t know if it works with mv.

NB: it does not bother with file content in any way, but if there are a /dir1/foo/name and a /dir1/bar/name it will end up with /dir2/name and /dir2/name~1~ and so on.