（13.1）判断主机存活3次机会

• eg：用数组

#!/usr/bin/bash
ip_list="10.18.40.1 10.48.42.127"
for ip in $ip_list  		##循环ip
do
	for count in {1..3} 		##每个ip给3次机会
	do
		ping -c1 -W1 $ip &>/dev/null
		if [ $? -eq 0 ];then
			echo "$ip ping is ok"
			break
		else
			echo "$ip ping is failure: $count"
			fail_count[$count]=$ip
		fi
	done
	if [ ${#fail_count[*]} -eq 3 ];then
		echo "${fail_count[1]} ping is failure"
		unset fail_count[*]
		##unset 清空数组
	fi
done

• 测试：
  
• eg2：ip.txt文件

10.18.40.1
10.18.42.127
10.18.42.4

#!/usr/bin/bash

while read ip  		##循环ip
do
	for count in {1..3} 		##每个ip给3次机会
	do
		ping -c1 -W1 $ip &>/dev/null
		if [ $? -eq 0 ];then
			echo "$ip ping is ok"
			break
		else
			echo "$ip ping is failure: $count"
			fail_count[$count]=$ip
		fi
	done
	if [ ${#fail_count[*]} -eq 3 ];then
		echo "${fail_count[1]} ping is failure"
		unset fail_count[*]
		##unset 清空数组
	fi
done < ip.txt

• 测试：
  
• eg3：用变量

while read ip
do
	fail_count=0
	for i in {1..3}
	do
		ping -c1 -W1 $ip &>/dev/null
		if [ $? -eq 0 ];then
			echo "$ip ping is ok"
			break
		else
			echo "$ip ping is failure: $i"
			let fail_count++
		fi
	done
	if [ $fail_count -eq 3 ];thrn
		echo "$ip ping is failure"
	fi
done < ip.txt

• 测试：
  
• eg：使用函数

ping_success()
{
	ping -c1 -W1 $ip &>/dev/null
	if [ $? -eq 0 ];then
		echo "$ip is ok"
		continue
	fi
}


while read ip
do
	ping_success		##若ping通，则不会走后面的2个ping_success，因为ping通continue了，continue是跳过后面的循环
	ping_success
	ping_success
	echo "$ip ping is failure"
done < ip.txt

• 测试