Convert Unix permissions between checkboxes, octal (755) and symbolic (rwxr-xr-x), including setuid, setgid and sticky.

How it works

Each of owner, group and others gets three bits: read = 4, write = 2, execute = 1. Their sum is one octal digit, so rwxr-xr-x = 7, 5, 5 = 755.

An optional fourth leading digit holds the special bits:

Bit	Value	On files	On directories
setuid	4000	runs as the file’s owner	(ignored on Linux)
setgid	2000	runs with the file’s group	new files inherit the directory’s group
sticky	1000	(ignored)	only the owner can delete their files, as in `/tmp`

In ls -l, a special bit replaces the execute character: s/t when execute is also set, S/T when it isn’t (usually a mistake).

References