The BASH command umask sets the default permissions for all further file creation. This command can also use the same symbolic codes used by chmod. For example, umask u+rw means that all future files create will automatically have read/write permissions granted to the user owner.
The root can set up a skeleton folder that will be used to create all further user accounts. This folder is located at /etc/skel. The permissions of /etc/skel are cloned to new user accounts when adduser is used. As a result, one can change the permissions of /etc/skel to change the default of user home directories.
For example, you can execute the following command to disable read permission from all “other” users.