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sleep(1)							     sleep(1)



NAME

  sleep	- Suspends execution for at least the specified	time

SYNOPSIS

  sleep	seconds

STANDARDS

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

  sleep:  XCU5.0

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

OPTIONS

  None

OPERANDS

  seconds
      Non-negative integer specifying the number of seconds for	which execu-
      tion is to be suspended.

DESCRIPTION

  The sleep command suspends execution of a process for	at least the interval
  specified by seconds,	which can range	from 0 to 2,147,483,647	seconds.
  Depending on system activity,	the actual time	of suspension may be longer.
  See the sleep(3) reference page.

  [Tru64 UNIX]	seconds	can be entered as a non-negative decimal, octal, or
  hexadecimal value.

NOTES

  If sleep receives a SIGALARM signal before process execution has resumed,
  sleep	takes one of the following actions:

   1.  Terminates normally with	a 0 (zero) exit	status.	 (See the sleep(3)
       reference page for more information.)

   2.  Ignores the signal

   3.  Performs	default	processing





EXIT STATUS

  The following	exit values are	returned:

  0   Execution	was successfully suspended for at least	the requested time,
      or a SIGALARM signal was received.

  >>0  An error occurred.

EXAMPLES

   1.  To display a message at 4-minute	intervals for 20 minutes, create a
       shell script called remind containing the following:


	    for	i
	    do
	    sleep 240; echo $i
	    sleep 240; echo $i
	    sleep 240; echo $i
	    sleep 240; echo $i
	    sleep 240; echo $i
	    done

       To display the message Try calling NHK at 4-minute intervals, enter:
	    remind 'Try	calling	NHK'

   2.  To run a	command	at regular intervals, create a shell script contain-
       ing the following:


	    while true
	    do
		    date
		    sleep 60
	    done

       This displays the date and time once a minute.

   3.  To execute a command after a specified interval,	enter the following;
	    (sleep 3600; echo Time\'s up) &&

       This displays the message "Time's up" after one hour.

ENVIRONMENT VARIABLES

  The following	environment variables affect the execution of sleep:

  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.

SEE ALSO

  Commands:  wait(1)

  Functions:  alarm(3),	pause(3), sigaction(2),	sleep(3)

  Standards:  standards(5)