sleep(1) [freebsd man page]

SLEEP(1)						    BSD General Commands Manual 						  SLEEP(1)

NAME

     sleep -- suspend execution for an interval of time

SYNOPSIS

     sleep seconds

DESCRIPTION

     The sleep command suspends execution for a minimum of seconds.

     If the sleep command receives a signal, it takes the standard action.  When the SIGINFO signal is received, the estimate of the amount of
     seconds left to sleep is printed on the standard output.

IMPLEMENTATION NOTES

     The SIGALRM signal is not handled specially by this implementation.

     The sleep command allows and honors a non-integer number of seconds to sleep in any form acceptable by strtod(3).	This is a non-portable
     extension, and its use will nearly guarantee that a shell script will not execute properly on another system.

EXIT STATUS

     The sleep utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

     To schedule the execution of a command for x number seconds later (with csh(1)):

	   (sleep 1800; sh command_file >& errors)&

     This incantation would wait a half hour before running the script command_file.  (See the at(1) utility.)

     To reiteratively run a command (with the csh(1)):

	   while (1)
		   if (! -r zzz.rawdata) then
			   sleep 300
		   else
			   foreach i (`ls *.rawdata`)
				   sleep 70
				   awk -f collapse_data $i >> results
			   end
			   break
		   endif
	   end

     The scenario for a script such as this might be: a program currently running is taking longer than expected to process a series of files, and
     it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata
     is created).  The script checks every five minutes for the file zzz.rawdata, when the file is found, then another portion processing is done
     courteously by sleeping for 70 seconds in between each awk job.

SEE ALSO

     nanosleep(2), sleep(3)

STANDARDS

     The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

HISTORY

     A sleep command appeared in Version 4 AT&T UNIX.

BSD
								  April 18, 1994							       BSD

sleep(1)						      General Commands Manual							  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 industry standards and associated tags.

OPTIONS

       None

OPERANDS

       Non-negative integer specifying the number of seconds for which execution 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:  Terminates  normally
       with a 0 (zero) exit status.  (See the sleep(3) reference page for more information.)  Ignores the signal Performs default processing

EXIT STATUS

       The  following  exit  values  are  returned: Execution was successfully suspended for at least the requested time, or a SIGALARM signal was
       received.  An error occurred.

EXAMPLES

       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' To run a command at regular intervals,
	      create a shell script containing the following:

	      while true do
		      date
		      sleep 60 done

	      This  displays  the date and time once a minute.	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: 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 vari-
       ables contain an invalid setting, the utility behaves as if none of the variables had been defined.  If set to a  non-empty  string  value,
       overrides  the  values of all the other internationalization variables.	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).  Determines the locale for the  for-
       mat  and  contents  of  diagnostic messages written to standard error.  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)

																	  sleep(1)