How to execute nohup cmd

Hi,

nohup sar -u 10 $COUNT |  awk 'NR>2 {$2=$4=$7="";}1' | tr -s '  ' '\t' 2>/dev/null >sar.out &

i have execute above line from shell script .. but sar.out is created with ZERO bite size..

Help on that what is the problem here

Thx,
Mani