umask applies to new files, setting their permissions in
accordance with the octal value provided. Notice that the mask is
negative, i.e. it will be subtracted from the permissions. You can use
this little table for some common permissions.
umask 022 => 777 - 022 => chmod 755
umask 077 => 777 - 077 => chmod 700
umask 002 => 777 - 002 => chmod 775
umask 007 => 777 - 007 => chmod 770
umask 027 => 777 - 027 => chmod 750
umask 177 => 777 - 177 => chmod 600umask is used in fstab.