【shell脚本】检查内存使用情况===chenkMen.sh

检查内存使用情况，当内存可使用等于100时，释放缓存

[root@localhost thy]#  cat checkMem.sh
#!/bin/bash
#防止内存溢出问题
used=`free -m | awk 'NR==2' | awk '{print $3}'`
free=`free -m | awk 'NR==2' | awk '{print $4}'`
echo "=======================================" >> /var/log/mem.log
data >> /var/log/mem.log
echo "Memory usage | [Use: ${used}MB][Free: ${free}MB]" >> /var/log/mem.log
if [ $free -le 100 ];then
    sync && echo 1 > /proc/sys/vm/drop_caches
    sync && echo 2 > /proc/sys/vm/drop_caches
    sync && echo 3 > /proc/sys/vm/drop_caches
    echo "OK" >> /var/log/mem.log
else
    echo "Not required" >> /var/log/mem.log

循环版本

[root@localhost thy]# cat ./clear_buff_cache.sh
#!/bin/bash
USED=`free -m | awk 'NR==2' | awk '{print $3}'`
FREE=`free -m | awk 'NR==2' | awk '{print $4}'`

while true;
do
    echo "===========================" >> /var/log/check_buff_cache.log
    date >> /var/log/check_buff_cache.log
    echo "Memory usage | [Use：${USED}MB][Free：${FREE}MB]" >> /var/log/check_buff_cache.log
    if [ $FREE -le  ] ; then
                sync && echo  > /proc/sys/vm/drop_caches
                sync && echo  > /proc/sys/vm/drop_caches
                sync && echo  > /proc/sys/vm/drop_caches
                echo "OK" >> /var/log/check_buff_cache.log
    else
                echo "Not required" >> /var/log/check_buff_cache.log
    fi
    sleep
done

监控内存和磁盘容量，小于给定值时报警

#!/bin/bash
# 实时监控本机内存和硬盘剩余空间，剩余内存小于500M,根分区剩余空间小于1000M时，发送报警邮件给root管理员

# 得到根分区、内存剩余空间
disk_size=$(df / | awk '/\//{print $4}')
mem_size=$(free | awk '/Mem/{print $4}')

# PS:内存和磁盘提取的空间大小是以kb为单位
while :
do
# 判断内存和磁盘容小于等于给定值时发送报警邮件
if [ $disk_size -le 1024000 -a $mem_size -le 512000 ];
then
        mail -s "Warning" root <<EOF
        Insufficient resources,资源不足
EOF
fi
done

注意EOF：

[root@VM_0_10_centos shellScript]# ./checkMem.sh
./checkMem.sh: line 18: warning: here-document at line 14 delimited by end-of-file (wanted `EOF')
./checkMem.sh: line 19: syntax error: unexpected end of file

PS：报如上错误是因为脚本中的EOF前面有空格。EOF前后都不应该有空格或其他符号

关于内存问题参考网址：https://www.cnblogs.com/muahao/p/6531772.html