1.\" Copyright (c) 1990, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 36.\" $FreeBSD: src/bin/sleep/sleep.1,v 1.15.2.3 2003/01/24 02:44:43 keramida Exp $ 37.\" $DragonFly: src/bin/sleep/sleep.1,v 1.2 2003/06/17 04:22:50 dillon Exp $ 38.\" 39.Dd April 18, 1994 40.Dt SLEEP 1 41.Os 42.Sh NAME 43.Nm sleep 44.Nd suspend execution for an interval of time 45.Sh SYNOPSIS 46.Nm 47.Ar seconds 48.Sh DESCRIPTION 49The 50.Nm 51command 52suspends execution for a minimum of 53.Ar seconds . 54.Pp 55If the 56.Nm 57command receives a signal, it takes the standard action. 58.Sh IMPLEMENTATION NOTES 59The 60.Dv SIGALRM 61signal is not handled specially by this implementation. 62.Pp 63The 64.Nm 65command will accept and honor a non-integer number of specified seconds 66(with a 67.Ql .\& 68character as a decimal point). 69.Bf Sy 70This is a non-portable extension, and its use will nearly guarantee that 71a shell script will not execute properly on another system. 72.Ef 73.Sh EXIT STATUS 74.Ex -std 75.Sh EXAMPLES 76To schedule the execution of a command for 77.Va x 78number seconds later (with 79.Xr csh 1 ) : 80.Pp 81.Dl (sleep 1800; sh command_file >& errors)& 82.Pp 83This incantation would wait a half hour before 84running the script command_file. 85(See the 86.Xr at 1 87utility.) 88.Pp 89To reiteratively run a command (with the 90.Xr csh 1 ) : 91.Pp 92.Bd -literal -offset indent -compact 93while (1) 94 if (! -r zzz.rawdata) then 95 sleep 300 96 else 97 foreach i (`ls *.rawdata`) 98 sleep 70 99 awk -f collapse_data $i >> results 100 end 101 break 102 endif 103end 104.Ed 105.Pp 106The scenario for a script such as this might be: a program currently 107running is taking longer than expected to process a series of 108files, and it would be nice to have 109another program start processing the files created by the first 110program as soon as it is finished (when zzz.rawdata is created). 111The script checks every five minutes for the file zzz.rawdata, 112when the file is found, then another portion processing 113is done courteously by sleeping for 70 seconds in between each 114awk job. 115.Sh SEE ALSO 116.Xr nanosleep 2 , 117.Xr sleep 3 118.Sh STANDARDS 119The 120.Nm 121command is expected to be 122.St -p1003.2 123compatible. 124.Sh HISTORY 125A 126.Nm 127command appeared in 128.At v4 . 129