osx man page for time

time(n) 						       Tcl Built-In Commands							   time(n)

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NAME
       time - Time the execution of a script

SYNOPSIS
       time script ?count?
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DESCRIPTION
       This  command  will  call  the  Tcl  interpreter count times to evaluate script (or once if count is not specified).  It will then return a
       string of the form
	      503 microseconds per iteration
       which indicates the average amount of time required per iteration, in microseconds.  Time is measured in elapsed time, not CPU time.

EXAMPLE
       Estimate how long it takes for a simple Tcl for loop to count to a thousand:
	      time {
		  for {set i 0} {$i<1000} {incr i} {
		      # empty body
		  }
	      }

SEE ALSO
       clock(n)

KEYWORDS
       script, time

Tcl																	   time(n)