Shell if else语句实战案例

判断文件，目录是否存在

-d filename 如果 filename为目录，则为真 
-f filename 如果 filename为常规文件，则为真 

目录：

path="/home"
#if [ ! -d ${path} ];then
if [ -d ${path} ];then
    echo dir ${path} exist!
else
    echo dir ${path} not exist!
fi

文件：

file="/home/log.txt"
if [ -f ${file} ];then
    echo file ${file} exist!
else
    echo file ${file} not exist!
fi

Nginx日志切割

#!/bin/bash
#auto mv nginx log shell
#by author test
S_LOG=/usr/local/nginx/logs/access.log
D_LOG=/data/backup/`date +%Y%m%d`
echo -e "\033[32mPlease wait start cut shell scripts...\033[1m"
sleep 2
if [ ! -d $D_LOG ];then
        mkdir -p  $D_LOG
fi
mv $S_LOG  $D_LOG
kill  -USR1  `cat /usr/local/nginx/logs/nginx.pid`
echo "-------------------------------------------"
echo "The Nginx log Cutting Successfully!"
echo "You can access backup nginx log $D_LOG/access.log files."

shell脚本检测Nginx服务是否正常启动，如果宕机，那么就设置邮箱报警 

#!/bin/bash
nx=`netstat -tpln | grep nginx | wc -l` #用这条命令也可以ps -ef | grep nginx | grep -v grep | grep master | wc -l

if [ $nx -eq 0 ];then
        /usr/local/nginx/sbin/nginx
fi

if [ $? -ne 0 ];then
echo "nginx is down send mail"  #如果nginx启动失败发送邮件，这里邮件可以自己配置
fi