1.\" $OpenBSD: sleep.1,v 1.22 2016/08/16 18:51:25 schwarze 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: August 16 2016 $ 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 ASYNCHRONOUS EVENTS 55.Bl -tag -width "SIGALRMXXX" 56.It Dv SIGALRM 57Terminate normally, with a zero exit status. 58.El 59.Sh EXIT STATUS 60.Ex -std sleep 61.Sh EXAMPLES 62Wait a half hour before running the script 63.Pa command_file 64(see also the 65.Xr at 1 66utility): 67.Pp 68.Dl (sleep 1800; sh command_file >& errors)& 69.Pp 70To repetitively run a command (with 71.Xr csh 1 ) : 72.Bd -literal -offset indent 73while (! -r zzz.rawdata) 74 sleep 300 75end 76foreach i (*.rawdata) 77 sleep 70 78 awk -f collapse_data $i >> results 79end 80.Ed 81.Pp 82The scenario for such a script might be: a program currently 83running is taking longer than expected to process a series of 84files, and it would be nice to have another program start 85processing the files created by the first program as soon as it is finished 86(when 87.Pa zzz.rawdata 88is created). 89The script checks every five minutes for this file. 90When it is found, processing is done in several steps 91by sleeping 70 seconds between each 92.Xr awk 1 93job. 94.Pp 95To monitor the growth of a file without consuming too many resources: 96.Bd -literal -offset indent 97while true; do 98 ls -l file 99 sleep 5 100done 101.Ed 102.Sh SEE ALSO 103.Xr at 1 104.Sh STANDARDS 105The 106.Nm 107utility is compliant with the 108.St -p1003.1-2008 109specification. 110.Pp 111The handling of fractional arguments is provided as an extension to that 112specification. 113.Sh HISTORY 114A 115.Nm 116utility appeared in 117.At v4 . 118