Advanced Chmod Calculator

Octal & Symbolic SUID/SGID Support Recursive Mode
Anish Nath
Permission Matrix
Special Flags
Owner
Group
Public
Read (4)
Write (2)
Execute (1)
Result
chmod 0755 filename
Quick Presets
Understanding Linux Permissions
The 4 Digits Explained

Permissions are often represented by 3 or 4 octal digits (e.g., 0755).

  • 1st Digit (Special): SUID (4) + SGID (2) + Sticky (1).
  • 2nd Digit (Owner): Permissions for the file owner.
  • 3rd Digit (Group): Permissions for the file's group.
  • 4th Digit (Public): Permissions for everyone else.
Symbolic Notation
Symbol Meaning Value
r Read 4
w Write 2
x Execute 1
s SUID/SGID -
t Sticky Bit -

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