chmod 555 Permission Explained: Read/Execute for All, No Write

Octal

555

Symbolic

r-xr-xr-x

Binary

101 101 101

Risk Level

Low Risk

Summary: Nobody can modify it without changing permissions first.

Class	Read (4)	Write (2)	Execute (1)	Octal
Owner (u)				5
Group (g)				5
Others (o)				5

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

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

555

r-xr-xr-x

Owner: read/execute · Group: read/execute · Others: read/execute

chmod 555 filename

Low Risk Any user can read this file — never use it for secrets such as keys or .env files.

View the full chmod 555 guide →

chmod 555 Breakdown

Class	Digit	Symbolic	On a file	On a directory
Owner (u)	`5`	`r-x`	Read and execute	Can list and enter
Group (g)	`5`	`r-x`	Read and execute	Can list and enter
Others (o)	`5`	`r-x`	Read and execute	Can list and enter

Is chmod 555 Safe?

Low Risk

Any user can read this file — never use it for secrets such as keys or .env files.
Even the owner cannot modify this file without changing permissions first.

When not to use it

Working directories where files are routinely created, updated, or deleted

Common Use Cases

Locked-down system binaries and read-only media directories
Archived read-only directory snapshots

chmod 555 Command Examples

# Apply using octal mode
chmod 555 filename

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

# Recursive command warning:
chmod -R 555 /path/to/dir
# Note: -R applies the same mode to files and directories. Use find to treat them separately:
find /path/to/dir -type d -exec chmod 555 {} +

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

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

umask Relationship

A umask of 222 makes new directories 555. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

What does chmod 555 mean?

Nobody can modify it without changing permissions first. In octal notation, the owner receives 5 (read/execute), the group receives 5 (read/execute), and others receive 5 (read/execute).

Is chmod 555 safe?

chmod 555 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 555 in symbolic notation?

In symbolic notation, chmod 555 is represented as r-xr-xr-x. You can apply this permission using the equivalent symbolic command "chmod u=rx,g=rx,o=rx filename".