chmod 634 Permission Explained
Summary: chmod 634 gives the owner read/write, the group write/execute, and everyone else read.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 6 | |||
| Group (g) | 3 | |||
| Others (o) | 4 |
chmod 634 filename
chmod 634 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 6 |
rw- |
Read and write | Can list names, cannot enter |
| Group (g) | 3 |
-wx |
Write and execute | Can enter and create/delete files, but not list |
| Others (o) | 4 |
r-- |
Read only | Can list names, but not enter |
Is chmod 634 Safe?
Moderate
- Every member of the group can modify 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
634 is uncommon in standard Linux setups. The closest widely used permission is chmod 664.
chmod 634 Command Examples
# Apply using octal mode
chmod 634 filename
# Apply using equivalent symbolic mode
chmod u=rw,g=wx,o=r filename
# Recursive command warning:
chmod -R 634 /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 634 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-rw--wxr-- 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 143 makes new directories 634. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 634 mean?
chmod 634 gives the owner read/write, the group write/execute, and everyone else read. In octal notation, the owner receives 6 (read/write), the group receives 3 (write/execute), and others receive 4 (read).
Is chmod 634 safe?
chmod 634 is classified as Moderate. Every member of the group can modify this file.
What is chmod 634 in symbolic notation?
In symbolic notation, chmod 634 is represented as rw--wxr--. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=wx,o=r filename".
Related Permissions
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