What in the heck is it? How does it work? The umask is a way to determine for a given user what the permissions of newly created files and directories have. Supposedly Linux wants 666 and 777 to be default perms for files and directories, respectively. Notice when you make a file, it’s set to 644, and directories to 755 though. That’s because this umask value is taking effect. On my machine anyway, the default umask is 022 (—-w–w-).

Because I always need to refer to this for some reason 4 - r 2 - w 1 - x Note: execute is required to change to a directory 4 - setuid 2 - setgid 1 - sticky