chmod 501 Permission Explained

Notice: This is an unusual permission set: some classes have more access than the class above them. It is rarely correct in practice.

Octal

501

Symbolic

r-x-----x

Binary

101 000 001

Risk Level

Low Risk

Summary: chmod 501 gives the owner read/execute, the group no access, and everyone else execute.

Class	Read (4)	Write (2)	Execute (1)	Octal
Owner (u)				5
Group (g)				0
Others (o)				1

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

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

501

r-x-----x

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

chmod 501 filename

Low Risk Even the owner cannot modify this file without changing permissions first.

View the full chmod 501 guide →

chmod 501 Breakdown

Class	Digit	Symbolic	On a file	On a directory
Owner (u)	`5`	`r-x`	Read and execute	Can list and enter
Group (g)	`0`	`---`	No access	Cannot list, enter, or modify
Others (o)	`1`	`--x`	Execute only	Can enter (cd) but not list contents

Is chmod 501 Safe?

Low Risk

Even the owner cannot modify this file without changing permissions first.
Unusual: a lower class has permissions the class above it lacks.

Common Use Cases

501 is uncommon in standard Linux setups. The closest widely used permission is chmod 500.

chmod 501 Command Examples

# Apply using octal mode
chmod 501 filename

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

# Recursive command warning:
chmod -R 501 /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 501 {} +

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

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

umask Relationship

A umask of 276 makes new directories 501. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

What does chmod 501 mean?

chmod 501 gives the owner read/execute, the group no access, and everyone else execute. In octal notation, the owner receives 5 (read/execute), the group receives 0 (no access), and others receive 1 (execute).

Is chmod 501 safe?

chmod 501 is classified as Low Risk. Even the owner cannot modify this file without changing permissions first.

What is chmod 501 in symbolic notation?

In symbolic notation, chmod 501 is represented as r-x-----x. You can apply this permission using the equivalent symbolic command "chmod u=rx,g=,o=x filename".