For the longest time I did not know what everything meant in htop.

I knew that load average 1.0 on my two core machine means that the CPU usage is at 50%. But why does it say 1.0?

I decided to look everything up and document it here.

They also say that the best way to learn something is to try to teach it.

Here is a screenshot of htop that I am going to describe.

Uptime shows how long the system has been running.

You can see the same information by running uptime:

$ uptime
 12:17:58 up 111 days, 31 min,  1 user,  load average: 0.00, 0.01, 0.05

How does the uptime program know that?

It reads the information from the file /proc/uptime.

9592411.58 9566042.33

The first number is the total number of seconds the system has been up. The second number is how much of that time the machine has spent idle, in seconds

Source: htop explained