Linux Permissions & Chmod Calculator
Interactive Linux permission matrix. Calculate 3-digit and 4-digit octal permissions (rwx, SUID, SGID, Sticky Bit) 100% offline & client-side.
Presets:
Special Flags
Owner (User)
Group
Others (World)
Octal Notation (3-digit):
644
Octal Notation (4-digit):
0644
Symbolic String (ls -l):
-rw-r--r--
CLI Command Example:
chmod 644 filename
Frequently Asked Questions (FAQ)
What is the difference between 3-digit and 4-digit chmod octal notation?
3-digit octal notation (e.g., 755) specifies permissions for Owner, Group, and Others. 4-digit octal notation (e.g., 0755 or 4755) includes the leading special bit (SUID=4, SGID=2, Sticky Bit=1).
What is SUID and SGID in Linux permissions?
SUID (Set User ID) allows a binary file to execute with the permissions of the file owner. SGID (Set Group ID) executes the binary with group permissions or enforces default group inheritance on directory contents.