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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
  command 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
       command described here, you must specify the full path /usr/bin/time.
       See the csh(1) reference page for a description of the built-in
       command.

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
  industry 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
  command 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
  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)

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
      multibyte characters in arguments).

  LC_MESSAGES
      Determines the locale for the format and contents of diagnostic
      messages 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)

Index for Section 1

Alphabetical listing for T

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