CHMOD CALCULATOR
Calculate Unix file permissions interactively. Toggle read, write, execute for owner, group, and others. Generates the octal code and chmod command instantly.
COMMON PRESETS
PERMISSIONS
Read
Write
Execute
OCTAL
OWNER
6
GROUP
4
OTHERS
4
SPECIAL BITS
OCTAL VALUE
SYMBOLIC rw-r--r--
DESCRIPTION
Owner: can read, write; Group: can read; Others: can read
CHMOD COMMAND
chmod 644 filename About chmod
chmod (change mode) is a Unix command that sets the permissions of files and directories. Permissions are defined for three entities: the owner, the group, and others.
Each entity can have read (r=4), write (w=2), and execute (x=1) permissions. The octal value is the sum of active bits per entity (e.g., read+write = 4+2 = 6).
Special bits: SetUID (4xxx) runs the file as the owner; SetGID (2xxx) inherits group; Sticky (1xxx) on directories prevents others from deleting files they don't own.