• chmod u+s xyz.sh → add SetUID (user-level special permission)
• chmod g+s xyz.sh → add SetGID (group-level special permission)
• chmod u-s xyz.sh → remove SetUID
• chmod g-s xyz.sh → remove SetGID
• find / -perm /6000 -type f → find all executables with SetUID/SetGID

⚠️ SetUID/SetGID works only for C/C++ compiled binaries, not Bash scripts.

Sticky Bit

• Protects files from deletion by non-owners
• Example: ls / → shows sticky bit as t in rwxrwxrwt

• chmod +t file/dir → assign sticky bit

  • Only the creator can delete contents of that folder, even with full permissions