check_mem

#!/bin/bash
#This Nagios plugin can be check you system memory status
USAGE_Method="$(basename $0) [-w|--warning] <Free Percent> [-c|--critical] <Free Percent>"
USAGE_Value="WARNING value must be large than CRITICAL value: `basename $0` $*"
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3
#设置Nagios 要求的状态
if [ $# -lt 4 ];then
echo
echo "Usage: $USAGE_Method"
echo
exit 0
fi
while [ $# -gt 0 ];do
case "$1" in
-w|--warning)
shift
WARNING=$1
;;
-c|--critical)
shift
CRITICAL=$1
;;
esac
shift
done
if [[ $WARNING -eq $CRITICAL || $WARNING -lt $CRITICAL ]]
then
echo
echo "$USAGE_Value"
echo
echo "Usage: $USAGE_Method"
echo
exit 0
fi
FREE_MEM=$(free -m | grep - | awk -F ' ' '{print $4}') #取当前未使用的内存，注意是未使用！
TOTAL_MEM=$(free -m | grep Mem | awk -F ' ' '{print $2}') #取当前系统总内存
PERCENT=$(bc <<< "scale=2;$FREE_MEM/$TOTAL_MEM" | tr '^.' ' ') #使用bc 输出百分比
if [ "$PERCENT" -le "$CRITICAL" ] #如果监测百分比小于等于用户设置的严重错误值，返回2
then
echo "CRITICAL - $FREE_MEM MB ($PERCENT%) Free Memory"
exit 2
fi
if [ "$PERCENT" -le "$WARNING" ] #如果百分比小于等于用户设置的警告值就警告并返回1
then
echo "WARNING - $FREE_MEM MB ($PERCENT%) Free Memory"
exit 1
fi
if [ "$PERCENT" -gt "$WARNING" ] #如果百分比大于用户设置的警告值就输出OK 返回0
then
echo "OK - $FREE_MEM MB ($PERCENT%) Free Memory"
exit 0
fi