NAME
time - time a simple command or give resource usage
Format
time [options] command [arguments...]
The time command runs the specified program command with the given arguments. When command finishes, time writes a message to standard error giving timing statistics about this program run. These statistics consist of
(i) the elapsed real time between invocation and termination,
(ii) the user CPU time (the sum of the tms_utime and tms_cutime values in a struct tms as returned by times.
(iii) the system CPU time (the sum of the tms_stime and tms_cstime values in a struct tms as returned by times.
real %e
user %U
sys %S
%e - Elapsed real time (in seconds).
%U - Total number of CPU-seconds that the process spent in user mode.
%S - Total number of CPU-seconds that the process spent in kernel mode.
Ex:
[root@nsk-linux ~]# time route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.2.0 0.0.0.0 255.255.255.0 U 1 0 0 eth4
0.0.0.0 10.0.2.2 0.0.0.0 UG 0 0 0 eth4
real 0m0.001s
user 0m0.000s
sys 0m0.001s
[root@nsk-linux ~]# time uptime
08:34:58 up 57 min, 2 users, load average: 0.04, 0.12, 0.08
real 0m0.003s
user 0m0.002s
sys 0m0.001s
For more option, please read man time.