bashスクリプトがカップ/メモリ/ディスクの使用量を監視する方法

#! /bin/bash

#Get the memory situation
mem_total=`free | awk 'NR==2{print $2}'` #Get the total memory size
mem_use=`free | awk 'NR==2{print $3}'` #Get memory usage size

#Statistic memory usage (size used/total size)
mem_use_rate=`awk 'BEGIN{print('$mem_use'/'$mem_total')*100}'| awk '{print int($0)}'`
#echo $mem_use_rate ----------

#get disk usage rate
disk_use_rate_str=`df -h | grep /dev/vda1 | awk -F '[ %]+' '{print $5}'| awk '{print int($0)}'`

# Get cpu usage rate
cpu_use_rate=`top -n 1 | grep Cpu |awk '{print $2}'| awk '{print int($0)}'`

#Alarm time
file_log=/home/error.log #create in advance
now_time=`date '+%F %T'`

function send_mail(){

}


function check(){

        if [[ "men_use_rate" > 50 ]] || [[ "disk_use_rate" > 50 ]] || [[ "cpu_use_rate" > 50 ]];then
                echo "Alarm time: "$now_time > $file_log
                echo "cpu usage:${cpu_use_rate}% --> disk usage: ${disk_use_rate}% --> memory usage: ${men_use_rate}%"
                send_mail
        fi
}

function main(){
        check
}
main

#! /bin/bash
var1=20
var2=3.14159
var3=`echo "scale=0;$var2 - $var1 " | bc`
echo $var3

var4=`echo "$var1 < $var2"| bc`
echo $var4

ps auxw|head -1;ps auxw|sort -rn -k4|head -40

#! /bin/bash
now=`date -u -d"+8 hour" +'%Y-%m-%d %H:%M:%S'`
#cpu usage threshold
cpu_warn='85'
#mem idle threshold
mem_warn='1000'
#disk usage threshold
disk_warn='90'

#--cpu
item_cpu () {
cpu_idle=`top -b -n 1 | grep Cpu | awk '{print $8}'|cut -f 1 -d ". "`
cpu_use=`expr 100 - $cpu_idle`
echo "$now Current cpu usage is $cpu_use" >> /tmp/monitoring.log
if [ $cpu_use -gt $cpu_warn ]
    then
        echo "cpu warning!!!! "
    else
        echo "cpu ok!!!! "
fi
}
#--mem
item_mem () {
#-MB as unit
mem_free=`free -m | grep "Mem" | awk '{print $4+$6}'`
echo "$now Current memory space remaining is ${mem_free}MB" >> /tmp/monitoring.log
if [ $mem_free -lt $mem_warn ]
    then
        echo "mem warning!!!! "
    else
        echo "mem ok!!!! "
                
fi
}
#--disk
item_disk () {
disk_use=`df -P | grep /dev/vda2 | grep -v -E '(tmp|boot)' | awk '{print $5}' | cut -f 1 -d "%"`
echo "$now Current disk usage is $disk_use" >> /tmp/monitoring.log
if [ $disk_use -gt $disk_warn ]
    then
        echo "disk warning!!! "
    else
        echo "disk ok!!! "
        
fi


}

item_cpu
item_mem
item_disk

#! /bin/bash
#!
total=$(free -m | sed -n '2p' | awk '{print $2}')
used=$(free -m | sed -n '2p' | awk '{print $3}')
free=$(free -m | sed -n '2p' | awk '{print $4}')
shared=$(free -m | sed -n '2p' | awk '{print $5}')
buff=$(free -m | sed -n '2p' | awk '{print $6}')
cached=$(free -m | sed -n '2p' | awk '{print $7}')
rate=`echo "scale=2;$used/$total" | bc | awk -F. '{print $2}'`
echo -e "total\tused\tfree\tshared\tbuffer\tavailable"
echo -e "${total}M\t${used}M\t${free}M\t${shared}M\t${buff}M\t${cached}M\nrate:${rate}%"
if [ $rate -ge 80 ]
then echo "Memory Warn"
    ps aux | grep -v USER | sort -rn -k4 | head
fi

#! /bin/bash
#!
DEV=`df -hP | grep '^/dev/*' | cut -d' ' -f1 | sort`
for I in $DEV
do dev=`df -Ph | grep $I | awk '{print $1}'`
size=`df -Ph | grep $I | awk '{print $2}'`
used=`df -Ph | grep $I | awk '{print $3}'`
free=`df -Ph | grep $I | awk '{print $4}'`
rate=`df -Ph | grep $I | awk '{print $5}'`
mount=`df -Ph | grep $I | awk '{print $6}'`
echo -e "$I:\tsize:$size\tused:$used\tfree:$free\trate:$rate\tmount:$mount"
F=`echo $rate | awk -F% '{print $1}'`
if [ $F -ge 80 ]; then
    echo "$mount Warn"
    else echo "It's OK"
fi
done