df output incorrect only produces yellow instead of red.

 
One of our solaris servers has had the /var partition fill up to 100%.
This has had a knock on effect of somehow killing the df command.
 
Not although the line below is displayed and is red the actual page has
only gone yellow. 
 
  Expected strings (capacity and Mounted) not found in df output

 
How do I change this so that the page goes red when I lose disk
reporting? Thanks.

 
Regards,

 
Craig Whilding

IT Systems Contractor

Mentor Graphics

1 Edward Court

Altrincham Business Park

Altrincham

WA14 5GL