Home/chmod 400

Chmod 400

Owner can read. Group has no permissions. Others have no permissions.

Numeric Notation

400

Symbolic Notation

r--------

Command

chmod 400 file

Permission Breakdown

Detailed view of permissions for each user category

Owner

✓ Read✗ Write✗ Execute

Group

✗ Read✗ Write✗ Execute

Others

✗ Read✗ Write✗ Execute

For Files

chmod 400 filename.txt

Changes permissions of a single file

chmod 400 *.txt

Changes permissions of all .txt files

After applying chmod 400, files will display as:

r-------- filename.txt

For Directories

chmod 400 dirname

Changes permissions of a directory

chmod -R 400 dirname

Recursively changes all files and subdirectories

After applying chmod 400, directories will display as:

dr-------- dirname

Common Use Cases for Chmod 400

Restricted Access

Files with restricted access, not available to public users.

General Purpose

This permission set is useful when you need owner read access.

General Purpose

This permission set is useful when you need owner read access.

Related Chmod Codes

Explore similar permission configurations

Try the Interactive Calculator

Experiment with different permission combinations

Understanding Chmod 400

The chmod 400 command sets specific file permissions in Linux and Unix systems. This permission configuration owner can read. group has no permissions. others have no permissions.

In the numeric notation 400, each digit represents the permission level for different user categories. The symbolic representation r-------- provides a visual way to understand these permissions, where 'r' means read, 'w' means write, 'x' means execute, and '-' means no permission.

When you execute chmod 400 filename, you're modifying the file's access control list to match this specific permission pattern. This is essential for maintaining proper security and access control in multi-user environments.