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SLEEP(1)		     General Commands Manual			SLEEP(1)

NAME
     sleep -- suspend execution for an interval of time

SYNOPSIS
     sleep number[unit] [...]

DESCRIPTION
     The  sleep  command suspends execution for a minimum of number seconds (the
     default, or unit s), minutes (unit m), hours (unit h), or	days  (unit  d).
     Intervals can be written in any form allowed by strtod(3).  If multiple in-
     tervals  are  given,  they are added together.  If the final sum is zero or
     negative, sleep exits immediately.

     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.

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

EXAMPLES
     To run a command after half an hour:

	   (sleep 0.5h; sh command_file >out 2>err)&

     This  incantation	would  wait  half  an  hour  before  running  the script
     command_file.  See the at(1) utility for another way to do this.

     To reiteratively run a command:

	   while :; do
		   if ! [ -r zzz.rawdata ] ; then
			   sleep 5m
		   else
			   for i in *.rawdata ; do
				   sleep 70
				   awk -f collapse_data "$i"
			   done >results
			   break
		   fi
	   done

     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  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(1) job.

SEE ALSO
     nanosleep(2), sleep(3)

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

     Support  for  non-integer intervals, units other than seconds, and multiple
     intervals which are added together are non-portable extensions first intro-
     duced in GNU sh-utils 2.0a (released in 2002).

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

FreeBSD ports 15.1		 March 22, 2024 			SLEEP(1)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=sleep&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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