#create a swap image
touch /var/swap.img
chmod 600 /var/swap.img
dd if=/dev/zero of=/var/swap.img bs=1024k count=1000 #1GB size
mkswap /var/swap.img
swapon /var/swap.img
free
echo "/var/swap.img    none    swap    sw    0    0" >> /etc/fstab