chmod 621 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

621

Symbolic

rw--w---x

Binary

110 010 001

Risk Level

Moderate

Summary: chmod 621 gives the owner read/write, the group write, and everyone else execute.

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

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

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

621

rw--w---x

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

chmod 621 filename

Moderate Every member of the group can modify this file.

View the full chmod 621 guide →

chmod 621 Breakdown

Class	Digit	Symbolic	On a file	On a directory
Owner (u)	`6`	`rw-`	Read and write	Can list names, cannot enter
Group (g)	`2`	`-w-`	Write only (rarely useful)	No practical effect without x
Others (o)	`1`	`--x`	Execute only	Can enter (cd) but not list contents

Is chmod 621 Safe?

Moderate

Every member of the group can modify this file.
Unusual: a lower class has permissions the class above it lacks.

Common Use Cases

621 is uncommon in standard Linux setups. The closest widely used permission is chmod 600.

chmod 621 Command Examples

# Apply using octal mode
chmod 621 filename

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

# Recursive command warning:
chmod -R 621 /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 621 {} +

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

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

umask Relationship

A umask of 156 makes new directories 621. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

What does chmod 621 mean?

chmod 621 gives the owner read/write, the group write, and everyone else execute. In octal notation, the owner receives 6 (read/write), the group receives 2 (write), and others receive 1 (execute).

Is chmod 621 safe?

chmod 621 is classified as Moderate. Every member of the group can modify this file.

What is chmod 621 in symbolic notation?

In symbolic notation, chmod 621 is represented as rw--w---x. You can apply this permission using the equivalent symbolic command "chmod u=rw,g=w,o=x filename".

Related Permissions

Change one bit:

chmod 221 remove owner read chmod 421 remove owner write chmod 721 add owner execute chmod 661 add group read chmod 601 remove group write chmod 631 add group execute chmod 625 add others read chmod 623 add others write chmod 620 remove others execute

← chmod 620 chmod 622 →

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