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) User Commands time(1) NAME
time - time a simple command SYNOPSIS
time [-p] utility [argument...] DESCRIPTION
The time utility invokes utility operand with argument, and writes a message to standard error that lists timing statistics for utility. The message includes the following information: o The elapsed (real) time between invocation of utility and its termination. o The User CPU time, equivalent to the sum of the tms_utime and tms_cutime fields returned by the times(2) function for the process in which utility is executed. o The System CPU time, equivalent to the sum of the tms_stime and tms_cstime fields returned by the times() function for the process in which utility is executed. When time is used as part of a pipeline, the times reported are unspecified, except when it is the sole command within a grouping command in that pipeline. For example, the commands on the left are unspecified; those on the right report on utilities a and c, respectively: time a | b | c { time a } | b | c a | b | time c a | b | (time c) OPTIONS
The following option is supported: -p Writes the timing output to standard error in the following format: real %f user %f sys %f < real seconds>, <user seconds>, <system seconds> OPERANDS
The following operands are supported: utility The name of the utility that is to be invoked. argument Any string to be supplied as an argument when invoking utility. USAGE
The time utility returns exit status 127 if an error occurs so that applications can distinguish "failure to find a utility" from "invoked utility exited with an error indication." The value 127 was chosen because it is not commonly used for other meanings. Most utilities use small values for "normal error conditions" and the values above 128 can be confused with termination due to receipt of a signal. The value 126 was chosen in a similar manner to indicate that the utility could be found, but not invoked. EXAMPLES
Example 1: Using the time command It is frequently desirable to apply time to pipelines or lists of commands. This can be done by placing pipelines and command lists in a single file. This single file can then be invoked as a utility, and the time applies to everything in the file. Alternatively, the following command can be used to apply time to a complex command: example% time sh -c 'complex-command-line' Example 2: Using time in the csh shell The following two examples show the differences between the csh version of time and the version in /usr/bin/time. These examples assume that csh is the shell in use. example% time find / -name csh.1 -print /usr/share/man/man1/csh.1 95.0u 692.0s 1:17:52 16% 0+0k 0+0io 0pf+0w See csh(1) for an explanation of the format of time output. example% /usr/bin/time find / -name csh.1 -print /usr/share/man/man1/csh.1 real 1:23:31.5 user 1:33.2 sys 11:28.2 ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of time: LANG, LC_ALL, LC_CTYPE, LC_MES- SAGES, LC_NUMERIC, NLSPATH, and PATH. EXIT STATUS
If utility is invoked, the exit status of time will be the exit status of utility. Otherwise, the time utility will exit with one of the following values: 1-125 An error occurred in the time utility. 126 utility was found but could not be invoked. 127 utility could not be found. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), shell_builtins(1), timex(1), times(2), attributes(5), environ( 5), standards(5) NOTES
When the time command is run on a multiprocessor machine, the total of the values printed for user and sys can exceed real. This is because on a multiprocessor machine it is possible to divide the task between the various processors. When the command being timed is interrupted, the timing values displayed may not always be accurate. BUGS
Elapsed time is accurate to the second, while the CPU times are measured to the 100th second. Thus the sum of the CPU times can be up to a second larger than the elapsed time. SunOS 5.10 1 Feb 1995 time(1)