经典脚本案例－－check memory

#!/bin/bash
STAT_OK=0
STAT_WARNING=1
STAT_CRITICAL=2
STAT_UNKNOWN=3
total_mem=`free -m |awk 'NR==2{print $2}'`
used_mem=`free -m |awk 'NR==3{print $3}'`
free_mem=`free -m |awk 'NR==3{print $4}'`
use_per=`echo "scale=2;$used_mem/$total_mem"|bc|sed 's/^.//g'`
#free_per=`echo "scale=2;$free_mem/$total_mem"|bc|sed 's/^.//g'`
#echo "$use_per"
help() {
    echo "USAGE:`basename $0` [-w] <used percent> [-c] <used percent> [-h]"
    exit -1
}
while getopts ":w:c:h" opt
do
    case $opt in
        w)  warning=$OPTARG
            ;;
        c)  critical=$OPTARG
            ;;
        h)  help
            ;;
                ?)      unkown=$OPTARG
            echo "error,plase check for help,USAGE:./`basename $0` -h"
            exit $STAT_UNKNOWN
                        ;;
    esac
done
if [[ $use_per -lt $warning ]]
then
        echo "OK - total:$total_mem MB,used:$used_mem MB,free:$free_mem MB | total_mem=$total_mem used_mem=$used_mem free_mem=$free_mem"
        exit $STAT_OK
                                                                                         
elif [[ $use_per -ge $warning ]] && [[ $use_per -lt $critical ]]
then
             echo "WARNING - total:$total_mem MB,used:$used_mem MB,free:$free_mem MB | total_mem=$total_mem used_mem=$used_mem free_mem=$free_mem"
             exit $STAT_WARNING
else
         echo "CRITICAL - total:$total_mem MB,used:$used_mem MB,free:$free_mem MB | total_mem=$total_mem used_mem=$used_mem free_mem=$free_mem"
             exit $STAT_CRITICAL
    fi
fi