SHELL 脚本小技巧

脚本很简单，直接上功能介绍及脚本，可以做模板使用：

1. 记录日志,记录脚本开始执行时间、结束时间
2. usage 函数，脚本需接参数执行，避免误执行，告诉用户，这个脚本的使用方法
3. 加锁，创建锁文件，脚本不允许多人同时执行，或脚本未执行结束又开始执行，尤其计划任务或数据库备份，避免这种问题
   

   #!/bin/bash
   #######################################################
   # $Version:      v1.0
   # $Function:     Shell Template Script
   # $Author:       Jerry.huang
   # $organization: http://www.cnblogs.com/Mrhuangrui
   # $Create Date:  2017-06-30 09:30
   # $Description:  You know what i mean,heiheihei
   #######################################################
   
   # Shell Env
   SHELL_DIR="/opt/shell"
   SHELL_LOG="${SHELL_DIR}/$0.log"
   LOCK_FILE="/tmp/$0.lock"
   
   #Write Log 
   shell_log(){
       LOG_INFO=$1
       echo "$(date "+%Y-%m-%d") $(date "+%H-%M-%S") : $0 : ${LOG_INFO}" >> ${SHELL_LOG}
   }
   
   # Shell Usage
   shell_usage(){
       echo $"Usage: $0 {backup}"
   }
   
   shell_lock(){
       touch ${LOCK_FILE}
   }
   
   shell_unlock(){
       rm -f ${LOCK_FILE}
   }
   
   # Backup MySQL All Database with mysqldump or innobackupex
   mysql_backup(){
       if [ -f "$LOCK_FILE" ];then
           shell_log "$0 is running"
           echo "$0" is running,exit now. && exit
       fi
       shell_log "mysql backup start"
       shell_lock
       sleep 10
       shell_log "mysql backup stop"
       shell_unlock
   }
   
   # Main Function
   main(){
       case $1 in
           backup)
               mysql_backup
               ;;
           *)
               shell_usage;
       esac
   }
   
   #Exec
   main $1