脚本之ping指定网段主机查看是否在线

这个脚本用到了函数，所以用几种方法实现：

1.功能在函数体中实现，主函数中调用该函数
代码：
[root@localhost ping_shell]# cat ping_1.sh 
#!/bin/bash
# simple ping shell
PING() {
        for i in {10..16}
        do
        if ping -c 1 -W 1 122.207.210.$i &> /dev/null      #用-c和-W选项是为了不让脚本等待很长时间，并且不让ping的结果输出到屏幕
        then
                echo "122.207.210.$i is up..."
        else
                echo "122.207.210.$i is down..."
        fi
        done
}

PING

结果：
[root@localhost ping_shell]# ./ping_1.sh 
122.207.210.10 is down...
122.207.210.11 is down...
122.207.210.12 is up...
122.207.210.13 is down...
122.207.210.14 is down...
122.207.210.15 is down...
122.207.210.16 is down...

2.函数体接受参数并打印信息，主函数中多次调用函数实现功能
代码：
[root@localhost ping_shell]# vim ping_2.sh 
#!/bin/bash
# simple ping shell
PING() {
        if ping -c 1 -W 1 $1 &> /dev/null
        then
                echo "$1 is up....."
        else
                echo "$1 is down..."
        fi
}
for i in {10..15}
do
PING 122.207.210.$i
done
结果：
[root@localhost ping_shell]# ./ping_2.sh 
122.207.210.10 is down...
122.207.210.11 is down...
122.207.210.12 is up.....
122.207.210.13 is down...
122.207.210.14 is down...
122.207.210.15 is down...

3.函数体接受参数且只有该函数的状态返回值，主函数中实现Ping功能
代码：
[root@localhost ping_shell]# cat ping_3.sh 
#!/bin/bash
# simple ping shell
PING() {
        if ping -c 1 -W 1 $1 &> /dev/null
        then
                return 0
        else
                return 1
        fi
}
for i in {10..15}
do
if PING 122.207.210.$i        #这里将参数传递给函数执行后返回执行状态结果（0|1），if语句接受该状态信息，为1则up，否则down
then
        echo "122.207.210.$i is up..."
else
        echo "122.207.210.$i is down..."
fi
done
结果：
[root@localhost ping_shell]# ./ping_3.sh 
122.207.210.10 is down...
122.207.210.11 is down...
122.207.210.12 is up...
122.207.210.13 is down...
122.207.210.14 is down...
122.207.210.15 is down...


如果是ping122.207.x.y这个网段的在线主机可以使这样：
代码：
[root@localhost ping_shell]# cat ping_4.sh 
#!/bin/bash
#
PING() {
        if ping -c 1 -W 1 $1 &>/dev/null
        then 
                return 0
        else
                return 1
        fi
}

for i in 210 211
do
  for j in 10 11 12
  do
        if PING 122.207.$i.$j
        then
                echo "122.207.$i.$j id up....."
        else
                echo "122.207.$i.$j is down..."
        fi
  done
done

结果：
[root@localhost ping_shell]# ./ping_4.sh 
122.207.210.10 is down...
122.207.210.11 is down...
122.207.210.12 id up.....
122.207.211.10 is down...
122.207.211.11 is down...
122.207.211.12 is down...