time <command> [-iterations <iterations>]
This is similar but not identical to the standard Tcl time
procedure. It will run the specified command for certain number of
iterations and return the time elapsed. The default number of
iterations is 1. Unlike the Tcl procedure, the time reported is the
total for all iterations, not the time per iteration.
Four time values are reported. active is the time elapsed while the process was being executed and when the system was executing on behalf of the process. user and system break this down into the two components. real is the real time elapsed. All times are in seconds.
To time 10 iterations of the train command (each doing 200
updates):
lens> time {train 200} -i 10
...
0.720 active 0.620 user 0.100 system 2.740 real