Chmod Permissions Calculator
Convert between Linux octal permissions (755, 644, 777) and symbolic notations (rwxr-xr-x) with bit breakdown and security notes. · Updated
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FAQ
What do numbers 7, 5, and 4 mean in chmod?
4 represents Read (r), 2 represents Write (w), and 1 represents Execute (x). 7 = 4+2+1 (rwx), 5 = 4+0+1 (r-x), and 4 = 4+0+0 (r--).
What permissions should I use for web files and directories?
Standard best practice is `755` (rwxr-xr-x) for directories and executable scripts, and `644` (rw-r--r--) for static files (HTML, CSS, images).
What permission should SSH private keys have?
SSH private keys (like ~/.ssh/id_rsa) must have `600` (rw-------) or `400` (r--------) so other users on the system cannot read them.
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