TIME(1) BSD General Commands Manual TIME(1)NAME
time — time command execution
SYNOPSIS
time [-clp] command [argument ...]
DESCRIPTION
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 the time builtin of
csh(1).
-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
(“POSIX.2”).
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 avail‐
able 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
swaps
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).
FILES
⟨sys/resource.h⟩
EXIT STATUS
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.
SEE ALSOcsh(1), ksh(1), clock_gettime(2), getrusage(2)STANDARDS
The time utility conforms to IEEE Std 1003.2-1992 (“POSIX.2”).
BUGS
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.
BSD November 9, 2011 BSD