Shell notes on how to check ip addresses occupied by scripts

Modify the script to check which ip addresses are occupied.

#! /Bin/bash

For I in {1 .. 10} // assign the I variable 1-10

Do // what to do

Ping-c1-w1 192.168.7. $ I &>/dev/null // ping 192.168.7

If [$? -Eq 0]; // whether the returned value is 0

Then // If the returned value is 0, do the following output:

Echo station $ I is up!

Else // otherwise

Echo station $ I is down! // Output this step

Fi done

Grant the script executable permission: chmod + x ipadd. sh

Run the script:

[Root @ localhost shellscripts] # ipadd. sh

Station1 is up!

Station2 is down!

Station3 is up!

Station4 is down!

Station5 is down!

Station6 is down!

Station7 is down!

Station8 is down!

Station9 is down!

Station10 is down!

======================================

[Root @ localhost shellscripts] # ping 192.168.7.3

PING 192.168.7.3 (192.168.7.3) 56 (84) bytes of data. 64 bytes from 192.168.7.3:

Icmp_seq = 1 ttl = 64 time = 0.043 MS 64 bytes from 192.168.7.3:

Icmp_seq = 2 ttl = 64 time = 0.040 MS ^ C --- 192.168.7.3

Ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1791 ms rtt min/avg/max/mdev = 0.040/0.041/0.043/0.006 ms

[Root @ localhost shellscripts] # echo $? // The ping command returns 0.

0 ====================================

[Root @ localhost shellscripts] # ping 192.168.7.4

PING 192.168.7.4 (192.168.7.4) 56 (84) bytes of data.

From 192.168.7.3 icmp_seq = 1 Destination Host Unreachable From 192.168.7.3

Icmp_seq = 2 Destination Host Unreachable From 192.168.7.3

Icmp_seq = 3 Destination Host Unreachable ^ C --- 192.168.7.4

Ping statistics --- 5 packets transmitted, 0 received, + 3 errors, 100% packet loss, time 4084 ms pipe 3

[Root @ localhost shellscripts] # echo $? 1 // ping failure. The return value is not 0.