ubuntu install security updates

1.su to root
   su

2.Show security updates only
   apt-get -s dist-upgrade | grep "^Inst" | grep -i securi | awk -F " " {'print $2'} | xargs apt-get install

3.Install security updates only
   apt-get -s dist-upgrade | grep "^Inst" | grep -i securi | awk -F " " {'print $2'} | xargs apt-get install