chmod 450 Permission Explained
Summary: chmod 450 gives the owner read, the group read/execute, and everyone else no access.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 4 | |||
| Group (g) | 5 | |||
| Others (o) | 0 |
chmod 450 filename
chmod 450 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 4 |
r-- |
Read only | Can list names, but not enter |
| Group (g) | 5 |
r-x |
Read and execute | Can list and enter |
| Others (o) | 0 |
--- |
No access | Cannot list, enter, or modify |
Is chmod 450 Safe?
Low Risk
- Even the owner cannot modify this file without changing permissions first.
- Unusual: a lower class has permissions the class above it lacks.
Common Use Cases
450 is uncommon in standard Linux setups. The closest widely used permission is chmod 440.
chmod 450 Command Examples
# Apply using octal mode
chmod 450 filename
# Apply using equivalent symbolic mode
chmod u=r,g=rx,o= filename
# Recursive command warning:
chmod -R 450 /path/to/dir
# Note: -R applies the same mode to files and directories. Use find to treat them separately:
find /path/to/dir -type f -exec chmod 450 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-r--r-x--- 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 327 makes new directories 450. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 450 mean?
chmod 450 gives the owner read, the group read/execute, and everyone else no access. In octal notation, the owner receives 4 (read), the group receives 5 (read/execute), and others receive 0 (no access).
Is chmod 450 safe?
chmod 450 is classified as Low Risk. Even the owner cannot modify this file without changing permissions first.
What is chmod 450 in symbolic notation?
In symbolic notation, chmod 450 is represented as r--r-x---. You can apply this permission using the equivalent symbolic command "chmod u=r,g=rx,o= filename".
Related Permissions
Change one bit: