What is octal used for?

Octal is commonly used in Unix/Linux file permissions and computing.

How do I read octal file permissions?

Each digit represents permissions: 7=rwx, 6=rw-, 5=r-x, 4=r--, 0=---.

Yes, the tool accepts the 0o prefix.

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Octal (base 8) is a numeral system using digits 0-7, commonly used in Unix file permissions.

What is octal used for?: Octal is commonly used in Unix/Linux file permissions and computing.
How do I read octal file permissions?: Each digit represents permissions: 7=rwx, 6=rw-, 5=r-x, 4=r--, 0=---.
Can I prefix with 0o?: Yes, the tool accepts the 0o prefix.

Last updated: 2026-05-24