Up time

Have you ever asked yourself how long your computer has been up and running?
In Linux, it is quite easy to know "up time".
In terminal type:

uptime

Here is an output example of this command:

02:44:01 up 1:23, 2 users, load average: 0.73, 1.60, 1.32

The first part shows current time, then "up time" in hh:mm format, then number of users conected to your computer, then system load averages for the past 1, 5, and 15 minutes.
Don't panic if you see more than one users are connected to your computer. If it is 2, one is your current session and the other is the terminal that you are using for "uptime" command.
If it shows more than 2 users, you may panic now!

Ok! Enough panicking!
In terminal type:

w

This is to see details of users reported by uptime command.