Updated: 2021/Apr/14

TIME(1)                     General Commands Manual                    TIME(1)

     time - time command execution

     time [-clpt] [-f fmt] command [argument ...]

     The time utility executes and times command.  After the command finishes,
     time writes the total elapsed time (wall clock time), ("real"), the CPU
     time spent executing command at user level ("user"), and the CPU time
     spent executing in the operating system kernel ("sys"), to the standard
     error stream.  Times are reported in seconds.

     Available options:

     -c      Displays information in the format used by default the time
             builtin of csh(1) uses (%Uu %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww).

     -f      Specify a time format using the csh(1) time builtin syntax.  The
             following sequences may be used in the format string:

             %U    The time the process spent in user mode in cpu seconds.
             %S    The time the process spent in kernel mode in cpu seconds.
             %E    The elapsed (wall clock) time in seconds.
             %P    The CPU percentage computed as (%U + %S) / %E.
             %W    Number of times the process was swapped.
             %X    The average amount in (shared) text space used in Kbytes.
             %D    The average amount in (unshared) data/stack space used in
             %K    The total space used (%X + %D) in Kbytes.
             %M    The maximum memory the process had in use at any time in
             %F    The number of major page faults (page needed to be brought
                   from disk).
             %R    The number of minor page faults.
             %I    The number of input operations.
             %O    The number of output operations.
             %r    The number of socket messages received.
             %s    The number of socket messages sent.
             %k    The number of signals received.
             %w    The number of voluntary context switches (waits).
             %c    The number of involuntary context switches.

     -l      Lists resource utilization information.  The contents of the
             command process's rusage structure are printed; see below.

     -p      The output is formatted as specified by IEEE Std 1003.2-1992

     -t      Displays information in the format used by default the time
             builtin of tcsh(1) uses (%Uu %Ss %E %P\t%X+%Dk %I+%Oio %Fpf+%Ww)
             with three decimal places for time values.

     Some shells, such as csh(1) and ksh(1), have their own and syntactically
     different built-in version of time.  The utility described here is
     available as /usr/bin/time to users of these shells.

   Resource Utilization
     If the -l option is given, the following resource usage information is
     displayed in addition to the timing information:
           maximum resident set size
           average shared memory size
           average unshared data size
           average unshared stack size
           page reclaims
           page faults
           block input operations
           block output operations
           messages sent
           messages received
           signals received
           voluntary context switches
           involuntary context switches
     Resource usage is the total for the execution of command and any child
     processes it spawns, as per wait4(2).


     The time utility exits with one of the following values:

     1-125   An error occurred in the time utility.

     126     The command was found but could not be invoked.

     127     The command could not be found.

     Otherwise, the exit status of time will be that of command.

     csh(1), ksh(1), clock_gettime(2), getrusage(2), wait4(2)

     The time utility conforms to IEEE Std 1003.2-1992 ("POSIX.2").

     The granularity of seconds on microprocessors is crude and can result in
     times being reported for CPU usage which are too large by a second.

NetBSD 9.99                      April 5, 2021                     NetBSD 9.99