内存使用率计算脚本

#!/bin/bash
free_M=`free  |grep '+' | awk  '{print $3}'|tr -d '\r'`
#echo $free_M
all_M=`free  |grep -i  'mem' | awk  '{print $2}'|tr -d '\r'`
#echo $all_M
#free_all=`echo "sce=2;$free_M/$all_M|bc"`
#free_all=`expr  $all_M / $free_M`
free_all=$(printf "%.6f" `echo "scale=6;$free_M/$all_M"|bc`)
echo $free_all
if_pd=`expr $free_all \> 0.6 `
if [ $if_pd -eq 1 ];then
    echo "dang"
fi