def guess_chimera_path(search_all=False):
    paths = _search_chimera(CHIMERA_BINARY, CHIMERA_LOCATIONS, CHIMERA_PREFIX,
                            search_all=search_all)
    if not paths and search_all:
        headless = '{0[0]}{1}{0[1]}'.format(os.path.split(CHIMERA_BINARY), '-headless')
        paths = _search_chimera(headless, CHIMERA_LOCATIONS, CHIMERA_PREFIX,
                                search_all=search_all)
    if not paths:
        sys.exit("Could not find UCSF Chimera.\n{}".format(_INSTRUCTIONS))
    return paths