Because it is 100% Java, it is available on every OS that supports Java 6 or later.
In order to follow this tutorial, you will need to have a computer that you can run JMeter on, and a web server to load test against.
You could see below output when you run your JMeter test.
It was little bit helpful & above summary gives decent amount of information you would need while the test is running.
It shows the minimum, maximum, average responses times, throughput, error count, no of active users for every 30 seconds .
But when the test runs for hours & when you have huge amount of summariser output in the console for every 30 seconds, It might be a bit difficult to understand the results.
For ex, If I would like to know the active user count at which the rate drops, I need to go through the summariser output line by line very carefully!