440
Octal
r--r-----
Symbolic
Safe
Security
What does chmod 440 mean?
chmod 440 gives read-only for owner and group. Owner and group can read, nobody can write. /etc/sudoers ships with 440 (owned by root) so it cannot be edited accidentally; use visudo to change it.
| Who | Digit | Symbolic | Permissions |
|---|---|---|---|
| Owner (user) | 4 | r-- | read |
| Group | 4 | r-- | read |
| Others | 0 | --- | no access |
Each digit is the sum of read (4), write (2) and execute (1). In ls -l the file shows as -r--r-----.
How to use chmod 440
# one file or directory
chmod 440 filename
# the same permissions in symbolic form
chmod u=r,g=r,o= filename
# a directory and everything inside it
chmod -R 440 directory/
# only regular files
find path/ -type f -exec chmod 440 {} +Need a different combination? Tick the boxes in the chmod calculator to get the octal and symbolic values instantly.
Chmod calculatorToggle read, write and execute for owner, group and others to build any permission.
Open the calculator Câu hỏi thường gặp
What does chmod 440 do?
It sets the permissions to r--r-----: the owner gets read, the group read and others no access.
What is 440 in symbolic notation?
r--r-----, or chmod u=r,g=r,o= as a symbolic chmod command.Is chmod 440 safe?
Yes, 440 does not give write access to other users.