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time(1)								      time(1)



NAME

  time - Times the execution of	a command

SYNOPSIS

  time [-p] command [argument...]

  The time command prints the elapsed time during the execution	of a command,
  the time spent in the	system,	and the	time spent in execution	of the com-
  mand on the diagnostic output	system.

				     Note

       The C shell has a built-in version of the time command.	If you are
       using the C shell, and want to guarantee	that you are using the com-
       mand described here, you	must specify the full path /usr/bin/time.
       See the csh(1) reference	page for a description of the built-in com-
       mand.

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  time:	 XCU5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

OPTIONS

  -p  Writes the timing	output to standard error.  This	is the default.

OPERANDS

  command
      The name of a command to be executed.  If	command	identifies any name
      specified	as a special built in your applicable shell reference page,
      the results are undefined	and unpredictable.

  argument
      The argument to be passed	to command.  See the appropriate reference
      pages for	these values.  This parameter may include flags	and arguments
      expected by command.









DESCRIPTION

  The time command prints the elapsed time during the execution	of a command,
  the time spent in the	system,	and the	time spent in execution	of the com-
  mand on the diagnostic output	system.	Time is	reported in seconds.

  The time command (with a different format) is	also built into	csh.

NOTES

  When time is used as part of a pipeline, the times reported are unspeci-
  fied,	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)

EXIT STATUS

  The time command returns the following exit values if	the command could not
  be invoked:

  1-125
      An error occurred	in the time command.

  126 The command specified by command was found but could not be invoked.

  127 The command specified by command could not be found.

  If the command was successfully invoked, the exit status of time is the
  exit status of command.

EXAMPLES

   1.  To measure the time required to run a program, enter:
	    time a.out

       This runs the program a.out and writes to the standard error output
       the amount of real, system, and user time that it uses:
	    real   10.5
	    user   0.3
	    sys	   3.6

   2.  To measure the time required by a complex command, enter:
	    time sh -c 'complex-cmmand-line'

       This runs all of	the commands, which may	include	pipelines, and
       returns the time	information for	the entire series of commands.

ENVIRONMENT VARIABLES

  The following	environment variables affect the execution of time:

  LANG
      Provides a default value for the internationalization variables that
      are unset	or null. If LANG is unset or null, the corresponding value
      from the default locale is used.	If any of the internationalization
      variables	contain	an invalid setting, the	utility	behaves	as if none of
      the variables had	been defined.

  LC_ALL
      If set to	a non-empty string value, overrides the	values of all the
      other internationalization variables.

  LC_CTYPE
      Determines the locale for	the interpretation of sequences	of bytes of
      text data	as characters (for example, single-byte	as opposed to multi-
      byte characters in arguments).

  LC_MESSAGES
      Determines the locale for	the format and contents	of diagnostic mes-
      sages written to standard	error.

  NLSPATH
      Determines the location of message catalogues for	the processing of
      LC_MESSAGES.

  PATH
      Determines the path used to locate command.

SEE ALSO

  Commands:  csh(1), ksh(1), Bourne shell sh(1b), POSIX	shell sh(1p)

  Functions:  times(3)

  Standards:  standards(5)