chmod 400

Only the owner can read. Nobody can write, including the owner (without changing the mode).

Octal Symbolic

File Directory

Permissions
	Read	Write	Execute
Owner	owner read	owner write	owner execute
Group	group read	group write	group execute
Others	others read	others write	others execute

Special bits: setuid setgid sticky

Path

Calculated on your device.

What chmod 400 means

400 (r--------) protects a secret from accidental edits as well as from other users. AWS, for example, asks for downloaded .pem key files to be set to 400 before using them with SSH.

Adjust the checkboxes above to see how a different mode compares, or go back to the chmod calculator.

Other common values

644 — Standard file
755 — Directories and programs
777 — Everyone can do everything
600 — Private file
700 — Private directory
775 — Shared team directory
664 — Group-editable file
2775 — Shared directory with setgid
1777 — Shared temp directory (sticky)