fort循环

目录

• for
  • 基础知识
  • 批量添加用户
  • 批量删除用户
  • 批量探测主机
  • 猜字游戏
  • 跳出
  • 分库分表备份
  • 主从状态监测

张贺，多年互联网行业工作经验，担任过网络工程师、系统集成工程师、LINUX系统运维工程师
笔者微信：zhanghe15069028807,现居济南历下区

for

基础知识

for (( i=10;i>=1;i--))
do
    echo num is $i
done

[root@test2 tmp]# /bin/bash test1.sh
num is 10
num is 9
num is 8
num is 7
num is 6
num is 5
num is 4
num is 3
num is 2
num is 1

#!/usr/bin/bash

a=10
b=1

for (( a>=1;b<=10; ))
do
	echo $a $b
	let a--
	let b++
done

[root@test2 tmp]# /bin/bash test1.sh
10 1
9 2
8 3
7 4
6 5
5 6
4 7
3 8
2 9
1 10

#!/usr/bin/bash
for (( a=1,b=9;a<10;a++,b-- ))
do
	num=$(( $a + $b ))
    echo num is $a + $b = $num
done

[root@test2 tmp]# /bin/bash test1.sh
num is 1 + 9 = 10
num is 2 + 8 = 10
num is 3 + 7 = 10
num is 4 + 6 = 10
num is 5 + 5 = 10
num is 6 + 4 = 10
num is 7 + 3 = 10
num is 8 + 2 = 10
num is 9 + 1 = 10

批量添加用户

#!/usr/bin/bash

for i in $(cat user.txt)
do
	user=$(echo $i|awk -F ":" '{print $1}')
	pass=$(echo $i|awk -F ":" '{print $2}')
	
	echo "用户是 $user   密码是$pass"
	id $user &>/dev/null
	if [ $? -eq 0 ];then
		echo "$user 已存在"
	else
		useradd $user 
		echo "$pass" | passwd --stdin $user &>/dev/null
	fi
done

#!/usr/bin/bash

read -p "请输入你要创建的用户前缀: " user_qz
read -p "请输入你要创建的用户数量: " user_num
echo "你创建的用户是 ${user_qz}1 ~ ${user_qz}${user_num}"

read -p "你要创建的用户如下，你确定要创建吗？[ y|n ] " readly


case $readly in
	y)
		for i in $(seq $user_num)
		do
			user=${user_qz}${i}
			id $user &>/dev/null
			if [ $? -eq 0 ];then
				echo "useradd: user $user already exists"
			else
				useradd $user
				echo "useradd: user $user add successfully."
			fi
		done
		;;
	n)
		echo "你想好了再创建......"
		exit
		;;
	*)
		echo "请不要乱输入...."
		exit 1

esac

#!/usr/bin/bash
if [  ! $UID -eq 0 ] && [ ! $USER == "root" ];then
	echo "无权限执行......"
	exit 
fi

read -p "请输入你要创建的用户前缀: " user_qz
if [ -z $user_qz ];then
	echo "请输入有效的值....."
	exit 
fi


read -p "请输入你要创建的用户数量: " user_num
if [[ ! $user_num =~ ^[0-9]+$ ]];then
	echo "请输入整数"
	exit 
fi


echo "你创建的用户是 ${user_qz}1 ..${user_qz}${user_num}"
read -p "你要创建的用户如下，你确定要创建吗？[ y/n ] " readly

case $readly in
	y|yes|YES)
		for i in $(seq $user_num)
		do
			user=${user_qz}${i}
			id $user &>/dev/null
			if [ $? -eq 0 ];then
				echo "useradd: user $user already exists"
			else
				useradd $user
				echo "useradd: user $user add successfully."
			fi
		done

		;;
	n|no|NO)
		
		;;
	*)
		echo "你想好了再创建......"
		;;
esac

#!/usr/bin/bash
if [  ! $UID -eq 0 ] && [ ! $USER == "root" ];then
	echo "无权限执行......"
	exit 
fi

read -p "请输入你要创建的用户前缀: " user_qz
if [ -z $user_qz ];then
	echo "请输入有效的值....."
	exit 
fi


read -p "请输入你要创建的用户数量: " user_num
if [[ ! $user_num =~ ^[0-9]+$ ]];then
	echo "请输入整数"
	exit 
fi

read -p "请输入你创建用户需要的统一密码: " user_pass

echo "你创建的用户是 ${user_qz}1 ..${user_qz}${user_num}"
read -p "你要创建的用户如下，你确定要创建吗？[ y/n ] " readly

case $readly in
	y|yes|YES)
		for i in $(seq $user_num)
		do
			user=${user_qz}${i}
			id $user &>/dev/null
			if [ $? -eq 0 ];then
				echo "useradd: user $user already exists"
			else
				useradd $user
				echo "$user_pass" | passwd --stdin $user &>/dev/null
				echo "useradd: user $user add successfully."
			fi
		done

		;;
	n|no|NO)
		
		;;
	*)
		echo "你想好了再创建......"
		;;
esac

#!/usr/bin/bash
if [  ! $UID -eq 0 ] && [ ! $USER == "root" ];then
	echo "无权限执行......"
	exit 
fi

read -p "请输入你要创建的用户前缀: " user_qz
if [ -z $user_qz ];then
	echo "请输入有效的值....."
	exit 
fi


read -p "请输入你要创建的用户数量: " user_num
if [[ ! $user_num =~ ^[0-9]+$ ]];then
	echo "请输入整数"
	exit 
fi

echo "你创建的用户是 ${user_qz}1 ..${user_qz}${user_num}"
read -p "你要创建的用户如下，你确定要创建吗？[ y/n ] " readly

case $readly in
	y|yes|YES)
		for i in $(seq $user_num)
		do
			user=${user_qz}${i}
			id $user &>/dev/null
			if [ $? -eq 0 ];then
				echo "useradd: user $user already exists"
			else
				user_pass=$(echo $((RANDOM))|md5sum |cut -c 2-10)
				useradd $user
				echo "$user_pass" | passwd --stdin $user &>/dev/null
				echo "用户: $user  密码: $user_pass" >> /tmp/user.log
				echo "useradd: user $user add successfully. cat /tmp/user.log"
			fi
		done

		;;
	n|no|NO)
		
		;;
	*)
		echo "你想好了再创建......"
		;;
esac

批量删除用户

#!/usr/bin/bash
if [  ! $UID -eq 0 ] && [ ! $USER == "root" ];then
	echo "无权限执行......"
	exit 
fi

read -p "请输入你要删除的用户前缀: " del_qz
if [ -z $del_qz ];then
	echo "请输入有效的值....."
	exit 
fi


read -p "请输入你要删除的用户数量: " user_num
if [[ ! $user_num =~ ^[0-9]+$ ]];then
	echo "请输入整数"
	exit 
fi

echo "你删除的用户是 ${del_qz}1 ..${del_qz}${user_num}"
read -p "你要删除的用户如下，你确定吗？[ y/n ] " readly

case $readly in
	y|yes|YES)
		for i in $(seq $user_num)
		do
			user=${del_qz}${i}
			id $user &>/dev/null
			if [ $? -eq 0 ];then
				userdel -r $user
				echo "$user 用户删除成功....."
			else
				echo "$user 用户不存在..."
			fi
		done
		;;
	n|no|NO)
			exit
		;;
	*)
		echo "你想好了再创建......"
		;;
esac

批量探测主机

#!/usr/bin/bash
#for (( 1=1;i<=254;i++))
> /tmp/ip.log

for i in {1..254}
do
	{
	ip=172.16.1.$i
	ping -c 1 -W 1 $ip &>/dev/null
	if [ $? -eq 0 ];then
		echo "$ip is ok"
		echo "$ip is ok" >>/tmp/ip.log
	else
		echo "$ip is down"
	fi
	} &
done
	wait
	echo "Sao Miao IP is Done"

	echo "Test SSH Port Starting......"


IFS=$'
'
for i in $(cat /tmp/ip.log)
do
	port_ip=$(echo $i |awk '{print $1}')
	nmap $port_ip |grep "22" &>/dev/null
	if [ $? -eq 0  ];then
		echo "$port_ip 22 is ok!!"
		echo "$port_ip 22 is ok!!" >> /tmp/port.log
	fi
done

猜字游戏

1. 随机输出一个1--100的数字
2. 要求用户输入的必须是数字
3. 输入的必须是数字
4. 如果比随机数小则表示比随机数小了，大则提示比随机数大了
5. 正确则退出 错误则继续死循环
6. 最后统计猜对了多少次，错了多少次

#!/usr/bin/bash

sj=$(echo $((RANDOM % 100 + 1 )))
echo $sj

i=0
while true
do
	read -p "请输入一个你需要猜的数字: " cc
	if [[ ! $cc =~ ^[0-9]+$ ]];then
		echo "请输入整数"
		continue
	fi

	#将用户的输入的数字与随机数进行比较
	if [ $cc -gt $sj ];then
		echo "你猜的太大"
	elif [ $cc -lt $sj ];then
		echo "你猜的太小，继续加油"
	else
		echo "猜对了....."
		break
	fi
	#进行数值自增
	let i++
done

	echo "你总共失败了多少次 $i"
	echo "你总共猜了多少次 $(( $i + 1 ))"

跳出

当我们使用循环语句进行循环的过程当中，有时候需要在未达到循环结束条件时强制跳出循环，那么shell给我们提供了内置的方法来实现该功能：exit，break，contunue。

• exit，直接退出脚本
• break，结束当前的循环，但会执行循环之后的所有代码
• contunue，忽略本次循环剩余的所有代码，直接进行下一次循环，直到循环结束。

//exit
for i in {1..3}
do
	echo 123
	exit
	echo 456
done
	echo 789
	
//执行结果
[root@test2 tmp]# /bin/bash 1.sh
123

//break
for i in {1..3}
do
	echo 123
	break
	echo 456
done
	echo 789

//效果
[root@test2 tmp]# /bin/bash 1.sh
123
789

//continue
for i in {1..3}
do
	echo 123
	continue
	echo 456
done
	echo 789
	
//效果
[root@test2 tmp]# /bin/bash 1.sh
123
123
123
789

分库分表备份

#!/usr/bin/bash

db_name=$(mysql -uroot -p123.com -e "show databases;"|sed 1d |grep -v ".*_schema")
DB_User=root
DB_Pass=123.com
Date=$(date +%F)

for database_name in $db_name
do
	#1.准备每个库的目录
	DB_Path=/mysql_dump/$database_name
	if [ ! -d $DB_Path ];then
		mkdir -p $DB_Path
	fi
	#2.备份数据库
	mysqldump -u$DB_User -p$DB_Pass --single-transaction 
	-B $database_name > $DB_Path/${database_name}_${Date}.sql
	echo -e "33[31m $database_name 数据库 已经备份完成..... 33[0m"
	
	#3.备份数据库的每一个表
	tb_name=$(mysql -u$DB_User -p$DB_Pass -e "use ${database_name};show tables;"|sed 1d)
	
	#4.批量的备份数据库的表
	for table_name in $tb_name
	do
		#5.备份数据库的表数据
		mysqldump -u$DB_User -p$DB_Pass --single-transaction 
		$database_name $table_name > $DB_Path/${database_name}_${table_name}_tables_${Date}.sql
		echo -e "33[32m 备份$database_name 的数据库中的 $table_name 数据表,备份成功 33[0m"
	done
done

主从状态监测

#!/usr/bin/bash
IO_Status=$(mysql -uroot -p123.com -e "show slave statusG"|awk '/Slave_IO_Running/ {print $2}')
SQL_Status=$(mysql -uroot -p123.com -e "show slave statusG"|awk '/Slave_SQL_Running/ {print $2}')


slave_sql_error_message(){
	mysql -uroot -p123.com -e "show slave statusG"|grep "Last_SQL" > /tmp/sql_err.log
	mail -s "MySQL Master SLave SQL Error $(date +%F)" 552408925@qq.com < /tmp/sql_err.log
	echo "邮件通知成功......"
}


slave_io_error_message(){
	mysql -uroot -p123.com -e "show slave statusG"|grep "Last_IO" > /tmp/io_err.log
	mail -s "MySQL Master SLave IO Error $(date +%F)" 552408925@qq.com < /tmp/io_err.log
	echo "邮件通知成功......"
}



if [ $IO_Status == "Yes" ] && [ $SQL_Status == "Yes" ];then
	echo "MySQL主从正常"
else
	#1.判断IO异常
	if [ ! $IO_Status == "Yes" ];then
		slave_io_error_message
		exit 
	fi

	#2.判断SQL异常
	if [ ! $SQL_Status == "Yes" ];then
		SQL_Err=$(mysql -uroot -p123.com -e "show slave statusG"|awk '/Last_SQL_Errno/ {print $2}')
		#3.精细化判断主从不同步的问题
		case $SQL_Err in 
			1007)
				echo "主从的SQL出现问题，尝试使用set global sql_slave_skip_counter=1; 跳过错误"
				sleep 2
				mysql -uroot -p123.com -e "stop slave;set global sql_slave_skip_counter=1;start slave;"
				SQL_Err_1=$(mysql -uroot -p123.com -e "show slave statusG"|awk '/Last_SQL_Errno/ {print $2}')
				if [ $SQL_Err_1 -eq 0 ];then
					echo "尝试跳过了一次，恢复MySQL数据库成功"
				else
					slave_sql_error_message
				fi
				;;
			1032)
					slave_sql_error_message
				;;
			*)
					slave_sql_error_message
		esac
	fi
fi