chmod 645 Permission Explained
Summary: chmod 645 gives the owner read/write, the group read, and everyone else read/execute.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 6 | |||
| Group (g) | 4 | |||
| Others (o) | 5 |
chmod 645 filename
chmod 645 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) | 5 |
r-x |
Read and execute | Can list and enter |
Is chmod 645 Safe?
Low Risk
- 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
645 is uncommon in standard Linux setups. The closest widely used permission is chmod 644.
chmod 645 Command Examples
# Apply using octal mode
chmod 645 filename
# Apply using equivalent symbolic mode
chmod u=rw,g=r,o=rx filename
# Recursive command warning:
chmod -R 645 /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 645 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-rw-r--r-x 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 132 makes new directories 645. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 645 mean?
chmod 645 gives the owner read/write, the group read, and everyone else read/execute. In octal notation, the owner receives 6 (read/write), the group receives 4 (read), and others receive 5 (read/execute).
Is chmod 645 safe?
chmod 645 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 645 in symbolic notation?
In symbolic notation, chmod 645 is represented as rw-r--r-x. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=r,o=rx filename".
Related Permissions
Change one bit: