1.\" $OpenBSD: sleep.1,v 1.19 2010/09/03 09:53:20 jmc Exp $ 2.\" $NetBSD: sleep.1,v 1.9 1995/07/25 19:37:43 jtc Exp $ 3.\" 4.\" Copyright (c) 1990, 1993, 1994 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the Institute of Electrical and Electronics Engineers, Inc. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 35.\" 36.Dd $Mdocdate: September 3 2010 $ 37.Dt SLEEP 1 38.Os 39.Sh NAME 40.Nm sleep 41.Nd suspend execution for an interval of time 42.Sh SYNOPSIS 43.Nm sleep 44.Ar seconds 45.Sh DESCRIPTION 46The 47.Nm 48utility 49suspends execution for a minimum of the specified number of 50.Ar seconds . 51This number must be positive and may contain a decimal fraction. 52.Nm 53is commonly used to schedule the execution of other commands (see below). 54.Sh EXIT STATUS 55The 56.Nm 57utility exits with one of the following values: 58.Pp 59.Bl -tag -width Ds -offset indent -compact 60.It 0 61On successful completion, or if the signal 62.Dv SIGALRM 63was received. 64.It \*(Gt0 65An error occurred. 66.El 67.Sh EXAMPLES 68Wait a half hour before running the script 69.Pa command_file 70(see also the 71.Xr at 1 72utility): 73.Pp 74.Dl (sleep 1800; sh command_file >& errors)& 75.Pp 76To repetitively run a command (with 77.Xr csh 1 ) : 78.Bd -literal -offset indent 79while (! -r zzz.rawdata) 80 sleep 300 81end 82foreach i (*.rawdata) 83 sleep 70 84 awk -f collapse_data $i >> results 85end 86.Ed 87.Pp 88The scenario for such a script might be: a program currently 89running is taking longer than expected to process a series of 90files, and it would be nice to have another program start 91processing the files created by the first program as soon as it is finished 92(when 93.Pa zzz.rawdata 94is created). 95The script checks every five minutes for this file. 96When it is found, processing is done in several steps 97by sleeping 70 seconds between each 98.Xr awk 1 99job. 100.Pp 101To monitor the growth of a file without consuming too many resources: 102.Bd -literal -offset indent 103while true; do 104 ls -l file 105 sleep 5 106done 107.Ed 108.Sh SEE ALSO 109.Xr at 1 , 110.Xr nanosleep 2 , 111.Xr setitimer 2 , 112.Xr alarm 3 , 113.Xr sleep 3 , 114.Xr usleep 3 115.Sh STANDARDS 116The 117.Nm 118utility is compliant with the 119.St -p1003.1-2008 120specification. 121.Pp 122The handling of fractional arguments is provided as an extension to that 123specification. 124