For example:
[alice@localhost cs253]$ time sleep 4 real 0m4.020s user 0m0.000s sys 0m0.000s [alice@localhost cs253]$
The command time gives the “real” (elapsed) time followed by time spent by the CPU in user mode as well in system mode. Due to programs potentially waiting for input and due to multiple users on a system the user plus system time is usually less than the real time reported by thetime command.