chmod 021 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

021

Symbolic

----w---x

Binary

000 010 001

Risk Level

Moderate

Summary: chmod 021 gives the owner no access, the group write, and everyone else execute.

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

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

Octal

Symbolic

Target File / Path

-R Recursive -v Verbose

021

----w---x

Owner: no access · Group: write · Others: execute

chmod 021 filename

Moderate Every member of the group can modify this file.

View the full chmod 021 guide →

chmod 021 Breakdown

Class	Digit	Symbolic	On a file	On a directory
Owner (u)	`0`	`---`	No access	Cannot list, enter, or modify
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 021 Safe?

Moderate

Every member of the group can modify this file.
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

021 is uncommon in standard Linux setups. The closest widely used permission is chmod 000.

chmod 021 Command Examples

# Apply using octal mode
chmod 021 filename

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

# Recursive command warning:
chmod -R 021 /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 021 {} +

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

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

umask Relationship

A umask of 756 makes new directories 021. Test umask values with our interactive Umask Calculator.

Frequently Asked Questions

What does chmod 021 mean?

chmod 021 gives the owner no access, the group write, and everyone else execute. In octal notation, the owner receives 0 (no access), the group receives 2 (write), and others receive 1 (execute).

Is chmod 021 safe?

chmod 021 is classified as Moderate. Every member of the group can modify this file.

What is chmod 021 in symbolic notation?

In symbolic notation, chmod 021 is represented as ----w---x. You can apply this permission using the equivalent symbolic command "chmod u=,g=w,o=x filename".

Related Permissions

Change one bit:

chmod 421 add owner read chmod 221 add owner write chmod 121 add owner execute chmod 061 add group read chmod 001 remove group write chmod 031 add group execute chmod 025 add others read chmod 023 add others write chmod 020 remove others execute

← chmod 020 chmod 022 →

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