Uptime

The uptime command shows the length of time since the system booted up. The output is displayed on the standard output.

break# uptime
2:49PM  up 229 days, 30 mins, 2 users, load averages: 0.00, 0.00, 0.00

The above shows that, at 2:49pm (when the command was run), the system in question had been running for 239 days and 30 minutes. It also had two users logged on. The three load averages values show the system utilisation as at 1, 5 and 15 minutes ago respectively.

Note: FreeBSD does not have an "uptime reset" issue such as most Linux and other unixlike OSes do.

See also w command.