chmod 600 Permission Explained: Owner Read/Write Only

Octal

600

Symbolic

rw-------

Binary

110 000 000

Risk Level

Restrictive

Summary: Only the owner can read or edit.

Class	Read (4)	Write (2)	Execute (1)	Octal
Owner (u)				6
Group (g)				0
Others (o)				0

setuid (4) setgid (2) sticky bit (1)

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

600

rw-------

Owner: read/write · Group: no access · Others: no access

chmod 600 filename

Restrictive

View the full chmod 600 guide →

chmod 600 Breakdown

Class	Digit	Symbolic	On a file	On a directory
Owner (u)	`6`	`rw-`	Read and write	Can list names, cannot enter
Group (g)	`0`	`---`	No access	Cannot list, enter, or modify
Others (o)	`0`	`---`	No access	Cannot list, enter, or modify

Is chmod 600 Safe?

Restrictive

This permission configuration follows standard Linux access control principles with no elevated risk indicators.

When not to use it

Shared team files and static web content that web server daemons must read

Common Use Cases

SSH private keys (e.g., ~/.ssh/id_ed25519, ~/.ssh/id_rsa)
SSH authorized_keys and known_hosts files
Environment files (.env) holding API tokens and database secrets

chmod 600 Command Examples

# Apply using octal mode
chmod 600 filename

# Apply using equivalent symbolic mode
chmod u=rw,g=,o= filename

# Recursive command warning:
chmod -R 600 /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 600 {} +

# Verify permissions
stat -c '%a %A %n' filename    # Linux
stat -f '%Lp %Sp %N' filename   # macOS

# Example ls -l output:
-rw------- 1 alice staff 1024 Jan 15 10:00 example.txt

umask Relationship

A umask of 177 makes new directories 600 and new files 600. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

What does chmod 600 mean?

Only the owner can read or edit. In octal notation, the owner receives 6 (read/write), the group receives 0 (no access), and others receive 0 (no access).

Is chmod 600 safe?

chmod 600 is classified as Restrictive. It follows standard Linux access patterns.

What is chmod 600 in symbolic notation?

In symbolic notation, chmod 600 is represented as rw-------. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=,o= filename".

Why does SSH reject keys that are not 600?

The SSH client checks the file mode of private key files before attempting authentication. If group or world permissions are present, SSH aborts with the message "UNPROTECTED PRIVATE KEY FILE!". This fail-closed design prevents other users or local processes from reading your private keys and compromising remote servers.