Umask defines the default permissions for files that are created on your linux system.

umask -S u=rwx,g=rw,o= umask -p 0027

You can change the permissions per user.

echo "umask 0023" >> ~/.bashrc

What the digits mean

• 0 = 7 - (4+2+1) = rwx
• 2 = 7 - (4+1) = rx
• 3 = 7 - (4) = r

Something like this. :)