The Sonar That Named a Command

The name ping comes from the sound a submarine's sonar makes: a short, sharp "ping" sent into the water, bouncing off objects and returning as an echo. In 1983, Mike Muuss needed a tool to track down odd behavior on his lab's IP network. He wrote a program that sends a packet and waits for a reply, exactly like sonar.

The name stuck because it perfectly describes what the command does. Send a signal, wait for the echo. If it comes back, the target is there. If it doesn't, something is blocking the way. The output even uses the word "icmp_seq", a sequence number for each pulse, just like sonar pings counted one by one.

Many Unix commands are named this way: the name tells you what it does. Once you see the connection, the command sticks in your memory.