shell脚本编写

#!/bin/bash
yum install epel-release -y
yum install nginx -y
ps aux |grep nginx |grep -v ‘grep‘
if [ $? -ne 0 ]
    then
        systemctl start nginx
fi
sed -ri ‘/^http/a upstream xzhweb\{‘ /etc/nginx/nginx.conf
sed -ri ‘/^upstream/a server 192.168.16.99‘ /etc/nginx/nginx.conf
sed -ri ‘/^server/a }‘ /etc/nginx/nginx.conf
sed -ri ‘/^server/a server 192.168.16.175‘ /etc/nginx/nginx.conf
sed -ri ‘/^\ +location \/ /a proxy_pass http://xzhweb;‘ /etc/nginx/nginx.conf
systemctl stop firewalld
setenforce 0
systemctl restart nginx
if [ $? -ne 0 ]
    then
       echo wellcome to congratulation
fi

#！/bin/bash
mem_used=`free | awk ‘NR==2{print $3}‘`
mem_total=`free | awk ‘NR==2{print $2}‘`
x=`expr "scale=2; $mem_used/$mem_total" |bc -l |cut -d. -f2`
if ((x>70)); then
        echo "Your memory is using $x\%, please handle as soon as possible."
    else
        echo "Your memory usage is $x%, can be at ease use!"
fi