Umask setting (cont)

Umask is slightly more confusing in the octal world

 $ umask -S
 u=rwx,g=rx,o=

 $ umask
 027

                               user   group  other
                                rwx    rwx    rwx

         if umask is 027        000    010    111
      then ~umask is            111    101    000


      directory default perms   111    111    111  == rwx rwx rwx
 bitwise AND with ~umask above  111    101    000  == rwx r-x ---
                                -----------------
                      yields    111    101    000  == rwx r-x ---