What is the `ping` command used for? [closed]

I'm doing some ping tests.

What does ping -c 1 mean? What can use this command for? Why would I find it in a bash script?

1 Answer

That command means to ping something 1 time (1 count). Without the -c, it will keep pinging the IP address until you tell it to stop. In scripting, I like to do a count of at least 2 in case the first ping fails.

You can use it to check if an IP address is live and then check for the results.

terrance@terrance-ubuntu:~$ ping -c 1 10.0.0.254
PING 10.0.0.254 (10.0.0.254) 56(84) bytes of data.
From 10.0.0.100 icmp_seq=1 Destination Host Unreachable
--- 10.0.0.254 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
terrance@terrance-ubuntu:~$ echo $?
1

The 1 above means it was not able to ping that address.

terrance@terrance-ubuntu:~$ ping -c 1 10.0.0.253
PING 10.0.0.253 (10.0.0.253) 56(84) bytes of data.
64 bytes from 10.0.0.253: icmp_seq=1 ttl=255 time=0.584 ms
--- 10.0.0.253 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.584/0.584/0.584/0.000 ms
terrance@terrance-ubuntu:~$ echo $?
0

The 0 above means the command exited without errors.

So in a script, you can use it like so:

#!/bin/bash
ping -c 2 10.0.0.253
case $? in
0) echo "The host is alive.";;
1) echo "The host is not responding.";;
esac

Hope this helps!