Default Permissions: `umask`¶

Default Permissions - `umask`¶

The U-Mask …

Bit field
Subtracted from default permissions at file/directory creation
Process attribute ⟶ inherited

umask in action¶

$ umask
0022
$ touch /tmp/file
$ ls -l /tmp/file

`umask`: How Does it Work?¶

umask subtracted from default permissions
umask is an (inherited) process attribute
Default permissions at file creation: rw-rw-rw-

Default permissions	`rw-rw-rw-`	`110 110 110`	`0666`
U-Mask	`----w--w-`	`000 010 010`	`0022`
Outcome	`rw-r--r--`	`110 100 100`	`0644`