shell创建swap交换分区

#!/bin/bash
read -p "请输入大小(单位:G):" i
o=`awk "BEGIN{printf $i*1024000}"`
dd if=/dev/zero of=/var/swapfile bs=1024 count=$o &> /dev/null
sleep 1
echo "/var/swapfile文件创建成功......"
/sbin/mkswap /var/swapfile &> /dev/null
sleep 1
echo "swapfile文件格式化并转换为swap分区......" 
/sbin/swapon /var/swapfile &> /dev/null
sleep 1
echo "挂载并激活分区......"
chmod -R 0600 /var/swapfile &> /dev/null
echo "请手动将新的swap分区添加到/etc/fstab里（/var/swapfile swap swap defaults 0 0）......"
free=`free -h | grep wap: | awk -F " " '{print $2}'`
echo "swap大小为$free"
exit 0