check status and run the job

I have one unix job which can be executed using following commands:

csh
setenv HOME /data/ftpqa/ARTQ/orascripts
sudo -u artq /apps/ralocal/bin/runscript artq ../out/art_neg_item_cost_update.csh

I want to create one more script, which checks whether art_neg_item_cost_update.csh is already running or not. If its not running that start the job else exit.

Please suggest how to write the script

i=0
while [ $i -le 1 ];do
prg="art_neg_item_cost_update.csh"
match=$(ps -eaf |grep "${prg}" |grep -v grep)
if [ -z "${match}" ] ; then
echo "$prg not running. Going to start..."
$PATH/$prg
else
echo "$prg already running. Output from ps: $match"
fi
i=$(( $i + 1 ))
done