time(1) [opendarwin man page]
TIME(1) BSD General Commands Manual TIME(1) NAME
time -- time command execution SYNOPSIS
time [-al] [-h | -p] [-o file] utility [argument ...] DESCRIPTION
The time utility executes and times the specified utility. After the utility finishes, time writes to the standard error stream, (in sec- onds): the total time elapsed, the time used to execute the utility process and the time consumed by system overhead. Available options: -a If the -o flag is used, append to the specified file rather than overwriting it. Otherwise, this option has no effect. -h Print times in a human friendly format. Times are printed in minutes, hours, etc. as appropriate. -l The contents of the rusage structure are printed as well. -o file Write the output to file instead of stderr. If file exists and the -a flag is not specified, the file will be overwritten. -p Makes time output POSIX.2 compliant (each time is printed on its own line). Some shells may provide a builtin time command which is similar or identical to this utility. Consult the builtin(1) manual page. ENVIRONMENT
The PATH environment variable is used to locate the requested utility if the name contains no '/' characters. DIAGNOSTICS
If utility could be timed successfully, its exit status is returned. If utility terminated abnormally, a warning message is output to stderr. If the utility was found but could not be run, the exit status is 126. If no utility could be found at all, the exit status is 127. If time encounters any other error, the exit status is between 1 and 125 included. SEE ALSO
builtin(1), csh(1), getrusage(2), wait(2) STANDARDS
The time utility is expected to conform to ISO/IEC 9945-2:1993 (``POSIX''). HISTORY
A time command appeared in Version 3 AT&T UNIX. BSD
June 6, 1993 BSD
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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 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 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 ALSO
csh(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