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.\" 38.Dd April 18, 1994 39.Dt SLEEP 1 40.Os 41.Sh NAME 42.Nm sleep 43.Nd suspend execution for an interval of time 44.Sh SYNOPSIS 45.Nm 46.Ar seconds 47.Sh DESCRIPTION 48The 49.Nm 50command 51suspends execution for a minimum of 52.Ar seconds . 53.Pp 54If the 55.Nm 56command receives a signal, it takes the standard action. 57.Sh IMPLEMENTATION NOTES 58The 59.Dv SIGALRM 60signal is not handled specially by this implementation. 61.Pp 62The 63.Nm 64command will accept and honor a non-integer number of specified seconds 65(with a 66.Ql .\& 67character as a decimal point). 68.Bf Sy 69This is a non-portable extension, and its use will nearly guarantee that 70a shell script will not execute properly on another system. 71.Ef 72.Sh EXAMPLES 73To schedule the execution of a command for 74.Va x 75number seconds later (with 76.Xr csh 1 ) : 77.Pp 78.Dl (sleep 1800; sh command_file >& errors)& 79.Pp 80This incantation would wait a half hour before 81running the script command_file. 82(See the 83.Xr at 1 84utility.) 85.Pp 86To reiteratively run a command (with the 87.Xr csh 1 ) : 88.Pp 89.Bd -literal -offset indent -compact 90while (1) 91 if (! -r zzz.rawdata) then 92 sleep 300 93 else 94 foreach i (`ls *.rawdata`) 95 sleep 70 96 awk -f collapse_data $i >> results 97 end 98 break 99 endif 100end 101.Ed 102.Pp 103The scenario for a script such as this might be: a program currently 104running is taking longer than expected to process a series of 105files, and it would be nice to have 106another program start processing the files created by the first 107program as soon as it is finished (when zzz.rawdata is created). 108The script checks every five minutes for the file zzz.rawdata, 109when the file is found, then another portion processing 110is done courteously by sleeping for 70 seconds in between each 111awk job. 112.Sh DIAGNOSTICS 113.Ex -std 114.Sh SEE ALSO 115.Xr nanosleep 2 , 116.Xr sleep 3 117.Sh STANDARDS 118The 119.Nm 120command is expected to be 121.St -p1003.2 122compatible. 123.Sh HISTORY 124A 125.Nm 126command appeared in 127.At v4 . 128