The uptime command is very handy to get a snapshot of info about the servers time since last reboot, and load.

Command:

$ uptime

Sample Results:

20:43:04 up 40 days, 13:43,  6 users,  load average: 2.03, 1.68, 1.5

Breakdown of results:
• The current time (20:43:04)
• How long the system has been running in days and hours (up 40 days 13:43)
• How many users are currently logged on (6 users)
• The system load averages for the past 1, 5, and 15 minutes (2.03, 1.68, 1.5)

This is the same information contained in the header line displayed by w and top command:

$ w
$ top

Note that w displays who is logged on and what they are doing.
The top command provides a dynamic real-time view of a running Linux/UNIX/BSD system.