The file ipupdate.txt should look like this:
ip.ip.ip.ip ctid
while read -r; do
ip=$REPLY
setip=`echo $ip|awk '{print $1}'`
ctid=`echo $ip|awk '{print $2}'`
echo "vzctl set $ctid --ipadd $setip --save"
vzctl set $ctid --ipadd $setip --save
done < ipupdate.txt
openvz, ip, updatethe, ipupdate, txt, ctid, reply, setip, echo, awk, quot, vzctl, ipadd,