chmod 646 Permission Explained
Summary: chmod 646 gives the owner read/write, the group read, and everyone else read/write.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 6 | |||
| Group (g) | 4 | |||
| Others (o) | 6 |
chmod 646 filename
chmod 646 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 6 |
rw- |
Read and write | Can list names, cannot enter |
| Group (g) | 4 |
r-- |
Read only | Can list names, but not enter |
| Others (o) | 6 |
rw- |
Read and write | Can list names, cannot enter |
Is chmod 646 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
646 is uncommon in standard Linux setups. The closest widely used permission is chmod 644.
chmod 646 Command Examples
# Apply using octal mode
chmod 646 filename
# Apply using equivalent symbolic mode
chmod u=rw,g=r,o=rw filename
# Recursive command warning:
chmod -R 646 /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 646 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-rw-r--rw- 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 131 makes new directories 646 and new files 646. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 646 mean?
chmod 646 gives the owner read/write, the group read, and everyone else read/write. In octal notation, the owner receives 6 (read/write), the group receives 4 (read), and others receive 6 (read/write).
Is chmod 646 safe?
chmod 646 is classified as Critical Risk. Anyone on the system can modify or replace this file.
What is chmod 646 in symbolic notation?
In symbolic notation, chmod 646 is represented as rw-r--rw-. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=r,o=rw filename".
Related Permissions
Change one bit: