Linux Permissions Calculator

Visually generate Unix file permissions. Toggle the grid to calculate octal (e.g., 755) and symbolic (e.g., -rwxr-xr-x) notation instantly.

Octal Value

644

Symbolic Value

-rw-r--r--

Scope

Read (4)

Write (2)

Execute (1)

Owner

User who owns the file

Group

Users in file's group

Public

Everyone else

Common Presets

Did you know?

The chmod command stands for "change mode". The permission numbers are just sums!

Read (r) = 4
Write (w) = 2
Execute (x) = 1

Chmod & Chown Reference

Command	Description	Example
`chmod +x file`	Make file executable	`chmod +x script.sh`
`chmod u+w file`	Add write permission for owner	`chmod u+w config.json`
`chmod -R 755 dir`	Recursively set permissions for directory	`chmod -R 755 /var/www/html`
`chown user:group file`	Change file ownership	`chown john:developers app.js`
`chown -R user:group dir`	Recursively change directory ownership	`chown -R www-data:www-data /var/www`
`chmod g-w file`	Remove write permission from group	`chmod g-w secret.txt`
`chmod o-r file`	Remove read permission from others	`chmod o-r private.key`

# Master Linux File Permissions

Understanding Linux file permissions is crucial for any developer or system administrator. The file permission system determines who can access files and directories on a Unix-like operating system. Permissions are defined for three types of users: Owner, Group, and Others.

Understanding the Numbers

The octal number notation (like 755 or 644) is calculated by adding up the values for each permission type:

Read (4): Allows opening and reading the file content.
Write (2): Allows modifying the file content.
Execute (1): Allows running the file as a program or script.