As rozcietrzewiacz has already commented, find -L
can have unexpected consequence of expanding the search into symlinked directories, so isn't the optimal approach. What no one has mentioned yet is that
find /path/to/search -xtype l
is the more concise, and logically identical command to
find /path/to/search -type l -xtype l
None of the solutions presented so far will detect cyclic symlinks, which is another type of breakage. this question addresses portability. To summarize, the portable way to find broken symbolic links, including cyclic links, is:
find /path/to/search -type l -exec test ! -e {} \; -print
For more details, see this question or ynform.org. Of course, the definitive source for all this is the findutils documentaton.