chmod 440 — what r--r----- means

When to use 440

A sensitive config or secrets file (API keys, credentials) that a service account's group must read but nobody should modify or world-read. A common hardening target for files that must never be 644.

Set it with chmod

Apply this permission to a file:

chmod 440 filename

Or apply it recursively to a directory and everything inside it:

chmod -R 440 directory/

Other common permissions

• chmod 777 rwxrwxrwx
• chmod 755 rwxr-xr-x
• chmod 644 rw-r--r--
• chmod 700 rwx------
• chmod 600 rw-------
• chmod 640 rw-r-----

Or build any permission with the interactive chmod calculator.