1.sticky bit : regardless of directory’s access, only directory’s owner can delete files.
(only for directories)
$> chmod 01755 dirname drwxr-xr-t
2.setuid bit: when you execute the program effective uid becomes as progams owner’s uid (such as passwd). Therefore , if execute bit is not set, this is meaningless
$> chmod 02755 exefile rwxr-sr-x $> chmod 04755 exefile rwsr-xr-x