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