On a FreeBSD machine, the above:
uptime | sed 's/, *[0-9]* users.*$//'
produces the same output as:
uptime
netmin@quasar|~(ttyp0) uptime | sed 's/, *[0-9]* users.*$//'
1:46PM up 21 days, 2:23, 1 user, load averages: 0.11, 0.08, 0.04
netmin@quasar|~(ttyp0) uptime
1:46PM up 21 days, 2:23, 1 user, load averages: 0.08, 0.08, 0.04