chmod 455 Permission Explained
Summary: chmod 455 gives the owner read, the group read/execute, and everyone else read/execute.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 4 | |||
| Group (g) | 5 | |||
| Others (o) | 5 |
chmod 455 filename
chmod 455 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) | 5 |
r-x |
Read and execute | Can list and enter |
Is chmod 455 Safe?
Low Risk
- Any user can read this file — never use it for secrets such as keys or .env files.
- 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
455 is uncommon in standard Linux setups. The closest widely used permission is chmod 555.
chmod 455 Command Examples
# Apply using octal mode
chmod 455 filename
# Apply using equivalent symbolic mode
chmod u=r,g=rx,o=rx filename
# Recursive command warning:
chmod -R 455 /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 455 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-r--r-xr-x 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 322 makes new directories 455. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 455 mean?
chmod 455 gives the owner read, the group read/execute, and everyone else read/execute. In octal notation, the owner receives 4 (read), the group receives 5 (read/execute), and others receive 5 (read/execute).
Is chmod 455 safe?
chmod 455 is classified as Low Risk. Any user can read this file — never use it for secrets such as keys or .env files.
What is chmod 455 in symbolic notation?
In symbolic notation, chmod 455 is represented as r--r-xr-x. You can apply this permission using the equivalent symbolic command "chmod u=r,g=rx,o=rx filename".
Related Permissions
Change one bit: