1.\" $NetBSD: sleep.1,v 1.19 2007/08/18 00:41:52 hubertf Exp $ 2.\" 3.\" Copyright (c) 1990, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the Institute of Electrical and Electronics Engineers, Inc. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 34.\" 35.Dd April 18, 1994 36.Dt SLEEP 1 37.Os 38.Sh NAME 39.Nm sleep 40.Nd suspend execution for an interval of time 41.Sh SYNOPSIS 42.Nm 43.Ar seconds 44.Sh DESCRIPTION 45The 46.Nm 47utility 48suspends execution for a minimum of 49.Ar seconds . 50It is usually used to schedule the execution of other commands (see 51.Sx EXAMPLES 52below). 53.Pp 54Note: The 55.Nx 56.Nm 57command will accept and honor a non-integer number of specified seconds. 58This is a non-portable extension, and its use will nearly guarantee that 59a shell script will not execute properly on another system. 60.Sh EXIT STATUS 61The 62.Nm 63utility exits with one of the following values: 64.Bl -tag -width flag 65.It Li \&0 66On successful completion, or if the signal 67.Dv SIGALRM 68was received. 69.It Li \&\*[Gt]\&0 70An error occurred. 71.El 72.Sh EXAMPLES 73To schedule the execution of a command for 1800 seconds later: 74.Pp 75.Dl (sleep 1800; sh command_file \*[Gt]\*[Am] errors)\*[Am] 76.Pp 77This incantation would wait a half hour before 78running the script command_file. 79(See the 80.Xr at 1 81utility.) 82.Pp 83To reiteratively run a command (with the 84.Xr csh 1 ) : 85.Pp 86.Bd -literal -offset indent -compact 87while (1) 88 if (! -r zzz.rawdata) then 89 sleep 300 90 else 91 foreach i (*.rawdata) 92 sleep 70 93 awk -f collapse_data $i \*[Gt]\*[Gt] results 94 end 95 break 96 endif 97end 98.Ed 99.Pp 100The scenario for a script such as this might be: a program currently 101running is taking longer than expected to process a series of 102files, and it would be nice to have 103another program start processing the files created by the first 104program as soon as it is finished (when zzz.rawdata is created). 105The script checks every five minutes for the file zzz.rawdata, 106when the file is found, then another portion processing 107is done courteously by sleeping for 70 seconds in between each 108awk job. 109.Sh SEE ALSO 110.Xr at 1 , 111.Xr nanosleep 2 , 112.Xr sleep 3 113.Sh STANDARDS 114The 115.Nm 116command is expected to be 117.St -p1003.2 118compatible. 119