chmod 666 Permission Explained: Read/Write for Everyone

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

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

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

666

rw-rw-rw-

Owner: read/write · Group: read/write · Others: read/write

chmod 666 filename Copy

Critical Risk Anyone on the system can modify or replace this file.

View the full chmod 666 guide →

chmod 666 Breakdown

Is chmod 666 Safe?

Critical Risk

• Anyone on the system can modify or replace this file.
• 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.

When not to use it

• Regular user files, server configurations, code repositories, and application logs

Common Use Cases

• Special virtual system character devices like /dev/null (managed by the kernel)

chmod 666 Command Examples

# Apply using octal mode
chmod 666 filename

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

# Recursive command warning:
chmod -R 666 /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 666 {} +

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

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

umask Relationship

A umask of 111 makes new directories 666 and new files 666. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

Related Permissions

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