There is a simple command in Linux that tells you how long your system has been running. The name of the command is uptime.

Uptime command gives a one line display that offers the following information -

The current time,

How long the system has been running,

How many users are currently logged on, and

The system load averages for the past 1, 5, and 15 minutes.

System load averages is the average number of processes that are either in a runnable or un-interruptable state.

When I ran the uptime command on my Ubuntu machine, I got the following output.

$ uptime
08:25:48 up 1:21, 2 users, load average: 1.00, 1.01, 1.03

From the output, we can infer that the current time is 8:25 AM, the machine has been running continuously without a reboot for 1 hr and 21 minutes, and there are 2 users currently logged in to the system.

The load average for the past 1, 5 and 15 minutes is 1.00, 1.01, and 1.03 respectively.

Uptime is a simple command that offers useful information to the system administrator.