LD_DEBUG: debugging ld.so on linux

David Baraff told me about this awesome way to see what ld.so is doing on linux.

    $ LD_DEBUG=help /bin/cat
    Valid options for the LD_DEBUG environment variable are:

    libs display library search paths
    reloc display relocation processing
    files display progress for input file
    symbols display symbol table processing
    bindings display information about symbol binding
    versions display version dependencies
    all all previous options combined
    statistics display relocation statistics
    unused determined unused DSOs
    help display this help message and exit

    To direct the debugging output into a file instead of standard output
    a filename can be specified using the LD_DEBUG_OUTPUT environment variable.