NAME    [Toc]    [Back]

     sleep -- suspend execution for an interval of time

SYNOPSIS    [Toc]    [Back]

     sleep seconds

DESCRIPTION    [Toc]    [Back]

     The sleep command suspends execution for a minimum of seconds.

     If the sleep command receives a signal, it takes the standard action.

IMPLEMENTATION NOTES    [Toc]    [Back]

     The SIGALRM signal is not handled specially by this implementation.

     The sleep command will accept and honor a non-integer number of specified
     seconds (with a `.' character as a decimal point).  This is a non-porta-
     ble extension, and its use will nearly guarantee that a shell script will
     not execute properly on another system.

EXAMPLES    [Toc]    [Back]

     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.

DIAGNOSTICS    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

     nanosleep(2), sleep(3)

STANDARDS    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

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


FreeBSD 5.2.1			April 18, 1994			 FreeBSD 5.2.1