How can I recreate a directory structure, without the files?

With GNU find(1), the following is likely to be the simplest solution. The second find statement recreates the entire file tree with empty "dummy" files (empty files with the same timestamps). (Feel free to replace the \; by + if your find supports it to reduce the number of mkdir/touch forks, and thus increase the performance of the command).

Be aware, though, that according to POSIX, the behaviour of find(1) is unspecified when {} not standing alone in an argument. Because of this, the following solutions are more portable than the previous.

With the cpio program:

or with GNU tar, and more verbose syntax:

This creates a list of directory names with find, non-recursively adds just the directories to an archive, and pipes it to a second tar instance to extract it at the target location.