Hence it is clear that the maximum number of bit is used to set permission for each user is 7,
which is a combination of read (4) write (2) and execute (1) operation. For example, if you set chmod 755, then it will look like as rwxr-xr-x.
But when special permission is given to each user it becomes SUID, SGID, and sticky bits. When extra bit “4” is set to user(Owner) it becomes SUID (Set user ID)
and when bit “2” is set to group it becomesSGID (Set Group ID)
and if other users are allowed to create or delete any file inside a directory then sticky bits “1” is set to that directory.
rws rws rwt
{UID} {GID} Sticky
S=4 S=2 t=1
