Systems Administration
Radiography: chmod 4755
Special bits: SUID, SGID, and Sticky Bit
4
100
Special (s/t)
SUID + - + -
7
111
User (u)
r + w + x
5
101
Group (g)
r + - + x
5
101
Others (o)
r + - + x
SUID (4)
Executes as file owner.
SGID (2)
Inherits group or executes as group.
Sticky (1)
Only owner can delete.
When to use?
Essential for files requiring elevated privileges (sudo, passwd) or shared directories.
Visual Impact
Displayed as s (SUID/SGID) or t (Sticky) instead of x.
4755
rwsr-xr-x. Common in system binaries.
2775
rwxrwsr-x. Useful for group collaboration.
1777
rwxrwxrwt. Standard for /tmp for security.
Warning!
Misuse can lead to critical security risks.
xeland314 S (4) • G (2) • T (1)