[Ask] About awk

[Morning Star <morning.star.crew@gmail.com>]

Hi guys,

I have some string and numeric data in like this format (one line):

1 2 3 4 5 6 7 8 9 10 11 12

and i want the output like this:

1 2 3

4 5 6

7 8 9

10 11 12

How do I do that in awk? 

Thanks in advance.

Greetings,

Marco