we have a file particular group(say abc) and we have a user(say def) in that group.I created file ram.txt it looked like this..
-rwxr--r-- 1 def abc 10 Oct 16 03:54 ram.txt

I changed the owner and group of the file as below
-rwxr--r-- 1 kriz test 10 Oct 16 03:58 ram.txt

when I log in as def to the machine and try to edit the file it says "read only" but when I save the file using wq!, it saves the contents and all the perm changes we did are lost and it agian goes to original settings..

Any Idea why it is happening? How to make a file readonly by chown option..