Here is a simple bash one-liner that takes a list of hosts to check via stdin and attempts to ping a host a single time. If no response is received within 1 second, it prints that hostname and moves onto the next host. It’s designed to work with the output of another command that outputs hostnames (for example, an inventory file.)

|awk '{print $6}'| xargs -I {} sh -c 'ping -c 1 -w 1 {} | grep -B1 100% |  head -1' | awk '{print $2}'

• Prints the 6th column of the output (you may or may not need this depending on what program is outputting hostnames)
• xargs takes the output from the previous command and runs the ping command against it in a subshell
  • ping -c1 to only do it once, -w1 to wait 1 second for timeout
  • grep for 100%, grab the line before it (100% in this case means packet loss)
  • head -1 only prints the first line of the ping results
• Awk prints only the second column in the resulting ping statistics output

It takes output like this:

PING examplehost (10.13.12.12) 56(84) bytes of data.

— examplehost ping statistics —
1 packets transmitted, 0 received, 100% packet loss, time 0ms

And simply outputs this:

examplehost

but only if the ping failed. No output otherwise.

I will note that the Anthropic’s Claude Sonnet AI helped me come to this conclusion, but not directly. Its suggestions for my problem didn’t work but were enough to point me in the right direction. The grep -B1 100% | head -1 portion need to be grouped together with the ping command in a separate shell, not appended afterward.