How can I list all files, but only in directories that have no subdirectories?

Question

I have a directory tree that I want to search recursively for all files of a certain type (for example all .jpg's), but I only want to list these files if they are at the bottom of a directory tree.

As an example if my tree looks like:

                          home
                          root
                   f1     f2     f3
                   f11    f22    f33
                   f111   f222   f333

and all folders have .jpg's, I only want to list the .jpg's in f111/f222/f333, and so on, and ignore the ones in the higher up folders.

I know that I can use a find command (like find . -name "*.jpg") to get a listing of all .jpg's in the entire tree, but I'm not sure how to limit it to only the bottom most folders without doing something like grep'ing the results to filter for 111/222/333's which isn't really feasible as I have hundreds of folders and I don't know what the last level folders might be named for all of them individually.

Answer 1

You can do this in two steps:

find . -type d -links 2 -print0 | xargs -0 -I{} find {} -name \*.jpg

The first command lists all directories without any subdirectories (since each subdirectory adds one to the link count, while an empty directory has two). The second invokes find manually on each of these results.

Answer 2

A POSIX equivalent of @TomHunt's solution.

find . -type d -links 2 -exec sh -c '
  find "$@" -type f -name "*.jpg"' sh {} +

The -links 2 relies on the property of some file systems that the link count of directories (initially 2 for the entry in their parent and the . entry in themselves) increases by one for every subdir (because of the .. entry in them). Some modern filesystems like btrfs or nilfs whose structures are radically different don't have such a property though.

With zsh, you could do something like:

has_subdirs() {
  local l
  l=($REPLY/*(/DNoN[1]))
  (($#l))
}
dirs_without_subdirs=(**/*(DN^+has_subdirs))
jpgs=($^dirs_without_subdirs/*.jpg(ND.))
(($#jpgs)) && printf '%s\n' $jpgs