chmod 661 Permission Explained
Summary: chmod 661 gives the owner read/write, the group read/write, and everyone else execute.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 6 | |||
| Group (g) | 6 | |||
| Others (o) | 1 |
chmod 661 filename
chmod 661 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 6 |
rw- |
Read and write | Can list names, cannot enter |
| Group (g) | 6 |
rw- |
Read and write | Can list names, cannot enter |
| Others (o) | 1 |
--x |
Execute only | Can enter (cd) but not list contents |
Is chmod 661 Safe?
Moderate
- Every member of the group can modify this file.
- Unusual: a lower class has permissions the class above it lacks.
Common Use Cases
661 is uncommon in standard Linux setups. The closest widely used permission is chmod 660.
chmod 661 Command Examples
# Apply using octal mode
chmod 661 filename
# Apply using equivalent symbolic mode
chmod u=rw,g=rw,o=x filename
# Recursive command warning:
chmod -R 661 /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 661 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-rw-rw---x 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 116 makes new directories 661. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 661 mean?
chmod 661 gives the owner read/write, the group read/write, and everyone else execute. In octal notation, the owner receives 6 (read/write), the group receives 6 (read/write), and others receive 1 (execute).
Is chmod 661 safe?
chmod 661 is classified as Moderate. Every member of the group can modify this file.
What is chmod 661 in symbolic notation?
In symbolic notation, chmod 661 is represented as rw-rw---x. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=rw,o=x filename".
Related Permissions
Change one bit: