Shell script to realize memory management and email alerts when memory usage is too high

One create email alert script

1.1 Install Mail Components

Use the Xmanager Enterprise 5 tool to import the software package into the /root directory of the Linux virtual machine, and

then perform a series of operations such as decompression, copying, and permissions

[root@localhost ~]# tar -zxvf sendEmail-v1.56.tar.gz 

[root@localhost ~]# cp sendEmail-v1.56/sendEmail /usr/local/bin/

[root@localhost ~]# chmod 755 /usr/local/bin/sendEmail

[root@localhost ~]# vim /opt/sendEmail.sh

1.2 Email configuration script

Need to modify the variables username, password, from_email_address in the script, where password is the QQ mailbox authorization code

#!/bin/bash
# 脚本的日志文件
LOGFILE="/tmp/Email.log"
:>"$LOGFILE"
exec 1>"$LOGFILE"
exec 2>&1

SMTP_server='smtp.qq.com'                                     # SMTP服务器，变量值需要自行修改
username='[email protected]'                             # 用户名，变量值需要自行修改
password='xxxxxxx'                                                  # 密码(QQ邮箱用的是授权码)，变量值需要自行修改
from_email_address='[email protected]'           #### 发件人Email地址，变量值需要自行修改
to_email_address="$1"                                                   # 收件人Email地址，tang传入的第一个参数
message_subject_utf8="$2"                                        # 邮件标题，root传入的第二个参数
message_body_utf8="$3"                                                  # 邮件内容，root传入的第三个参数

# 转换邮件标题为GB2312，解决邮件标题含有中文，收到邮件显示乱码的问题。
message_subject_gb2312=`iconv -t GB2312 -f UTF-8 << EOF
$message_subject_utf8
EOF`
[ $? -eq 0 ] && message_subject="$message_subject_gb2312" || message_subject="$message_subject_utf8"

# 转换邮件内容为GB2312，解决收到邮件内容乱码
message_body_gb2312=`iconv -t GB2312 -f UTF-8 << EOF
$message_body_utf8
EOF`
[ $? -eq 0 ] && message_body="$message_body_gb2312" || message_body="$message_body_utf8"

# 发送邮件
sendEmail='/usr/local/bin/sendEmail'
set -x
$sendEmail -s "$SMTP_server" -xu "$username" -xp "$password" -f "$from_email_address" -t "$to_email_address" -u "$message_subject" -m "$message_body" -o message-content-type=text -o message-charset=gb2312

1.3 Send mail test

[root@localhost ~]# chmod +x /opt/sendEmail.sh

[root@localhost ~]# /opt/sendEmail.sh    [email protected]  warning   warning

Two memory management

Write a memory monitoring script in the shell, and send an email alert when the usage exceeds 80%.

Filter the total and used in the memory information. Here, use the awk tool

#!/bin/bash
total=`free -m |awk 'NR==2{print $2}'`
used=$[`free -m |awk 'NR==2{print $3}'`*1000]		#由于无法进行浮点数计算，所以此处把被除数和商扩大1000倍，效果一样
bi=$[$used / $total]
if [ $bi -gt 800 ];then
 /opt/sendEmail.sh    [email protected] warning warning!!!
fi

Email successfully received