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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.

IMPLEMENTATION NOTES

     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

     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 com-
     mand_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 run-
     ning 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 cre-
     ated).  The script checks every five minutes for the file zzz.rawdata,
     when the file is found, then another portion processing is done courte-
     ously by sleeping for 70 seconds in between each awk job.

DIAGNOSTICS

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

SEE ALSO

     nanosleep(2), sleep(3)

STANDARDS

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