Hints on what freedup lacks

  1. Processing directories
    some operating systems support linking of directories on some file systems with the link (not ln) command. Since the testing environment does not provide such functionality, there is no option for it. On the other hand, it would probably not significantly change the file system size.
  2. Removing empty files or directories
    With Linux this a simple command line would do it for directories:
    find ./ -type d -empty -print0 | xargs -0 rmdir
    and another one for empty files
    find ./ -type f -empty -print0 | xargs -0 rm
    Both lines allow to use line feeds within the file names, since they use zero limited strings (This hint is from the readme of dupmerge).
    With a non GNU-like OS this command line would do it for directories:
    find ./ -type d -size 0c -print | xargs rmdir
    and a similar one for empty files:
    find ./ -type f -size 0c -print | xargs rm