🔑 Extended Chmod Permissions Calculator (4-Bit)
| Category / Role | Read (4) / SUID (4) | Write (2) / SGID (2) | Execute (1) / Sticky (1) |
|---|---|---|---|
| Special Bits | |||
| Owner (u) | |||
| Group (g) | |||
| Other (o) |
Octal Notation
0744
Symbolic Notation
-rwxr--r--
Command
chmod 0744 file
Special Permissions
4 SUID (Set User ID)
Executes the file with the permissions of the file owner, rather than the user who ran it. (Commonly used for programs like passwd so regular users can temporarily act as root to change their password).
2 SGID (Set Group ID)
• On a file: Runs the file with the privileges of the file's group.
• On a directory: Forces any new file created inside to inherit the directory's group, rather than the creator's group (great for shared team folders).
1 Sticky Bit
Primarily used on directories. Restricts file deletion so that only the file's owner (or root) can delete or rename a file inside that directory, even if other users have write access. (Commonly used on the public /tmp folder).