On both Linux & Unix umask uses the following numbers for permissions:
0 - read, write and execute
1 - read and write
2 - read and execute
3 - read only
4 - write and execute
5 - write only
6 - execute only
7 - no permission
Enter the command umask followed by the new default permissions:
xen root # umask 027
This value would set the following permissions on all files I create going
forward:
owner - read, write and execute
group - read and execute
world - no permissions; cannot read, write or execute