Dangling symlinks

On many OSs, you can have 'dangling' symlinks:

  $ ln -s nada dangling

  $ ls -l nada realfile dangling
  -rw-r--r--    1 reegen  reegen  151 Sep 17 10:00 realfile 
  lrwxrwxrwx    1 reegen  reegen   10 Sep 17 10:00 dangling -> nada
  ls: nada: No such file or directory

  $ perl -e '$_="realfile"; print "$_ Exists\n" if -e $_'
  realfile Exists

  $ perl -e '$_="nada"; print "$_ Exists\n" if -e $_'

  $ perl -e '$_="dangling"; print "$_ Exists\n" if -e $_'