set user id and set group id

when we give chmod 0777 file first no is for suid sgid n sticky bit n their combination
rest three are for ugo

111 left most for suid
middle for sgid
lst right for sticky

0 000 none
1 001 sticky
2 010 sgid
3 011 sgid + stick
4 100 suid
5 101 suid + stick
6 110 suid + sgid
7 111 suid + sgid + sticky bit


so chmod 4644 file result in 100 110 100 100 i.e rwSr--r--
chmod 6654 file result in 110 110 101 100 i.e rwSr-Sr--
chmod 3646 file result in 011 110 100 110 i.e rw-r-SrwT