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OpenSolaris 2009.06 - man page for time (opensolaris section 1)

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  infor-
       mation:

	   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 com-
       mands on the left are unspecified; those on the right report on utilities a and c, respec-
       tively:

	 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\nuser %f\nsys %f\n < 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 dis-
       tinguish "failure to find a utility" from "invoked utility exited with  an  error  indica-
       tion."  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 simi-
       lar 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_MESSAGES, LC_NUMERIC,  NLSPATH, and PATH.

EXIT STATUS
       If utility is invoked, the exit status of time will be the exit status of utility.  Other-
       wise, 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  pos-
       sible 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 sec-
       ond. Thus the sum of the CPU times can be up to a second larger than the elapsed time.

SunOS 5.11				    1 Feb 1995					  time(1)


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