this article speaks indeed the truth
Let’s say you want to make all files you create read writable by all other users then you would set a
umask
in unix. Well, OS X is a bit different here. What worked for me was:
sudo chmod g+w /Library/Preferences/.GlobalPreferences.plist
open $!
The plist editor should come up (if you have Xcode installed).
Select the root branch and add a child called
NSUmask
and change its type to
number
save. reboot. enjoy
if you hose your system by doing this, then let me remind you that I don’t take responsibility for that.