chmod 256 Permission Explained
Summary: chmod 256 gives the owner write, the group read/execute, and everyone else read/write.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 2 | |||
| Group (g) | 5 | |||
| Others (o) | 6 |
chmod 256 filename
chmod 256 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 2 |
-w- |
Write only (rarely useful) | No practical effect without x |
| Group (g) | 5 |
r-x |
Read and execute | Can list and enter |
| Others (o) | 6 |
rw- |
Read and write | Can list names, cannot enter |
Is chmod 256 Safe?
Critical Risk
- Anyone on the system can modify or replace this file.
- Any user can read this file — never use it for secrets such as keys or .env files.
- Unusual: a lower class has permissions the class above it lacks.
Common Use Cases
256 is uncommon in standard Linux setups. The closest widely used permission is chmod 644.
chmod 256 Command Examples
# Apply using octal mode
chmod 256 filename
# Apply using equivalent symbolic mode
chmod u=w,g=rx,o=rw filename
# Recursive command warning:
chmod -R 256 /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 256 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
--w-r-xrw- 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 521 makes new directories 256. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 256 mean?
chmod 256 gives the owner write, the group read/execute, and everyone else read/write. In octal notation, the owner receives 2 (write), the group receives 5 (read/execute), and others receive 6 (read/write).
Is chmod 256 safe?
chmod 256 is classified as Critical Risk. Anyone on the system can modify or replace this file.
What is chmod 256 in symbolic notation?
In symbolic notation, chmod 256 is represented as -w-r-xrw-. You can apply this permission using the equivalent symbolic command "chmod u=w,g=rx,o=rw filename".
Related Permissions
Change one bit: