1.\" $NetBSD: sleep.1,v 1.23 2016/08/12 02:36:38 sevan 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 August 12, 2016 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.Pp 61When the 62.Dv SIGINFO 63signal is received, the estimate of the amount of seconds left to 64sleep is printed on the standard output. 65.Sh EXIT STATUS 66The 67.Nm 68utility exits with one of the following values: 69.Bl -tag -width flag 70.It Li \&0 71On successful completion, or if the signal 72.Dv SIGALRM 73was received. 74.It Li \&\*[Gt]\&0 75An error occurred. 76.El 77.Sh EXAMPLES 78To schedule the execution of a command for 1800 seconds later: 79.Pp 80.Dl (sleep 1800; sh command_file \*[Gt]\*[Am] errors)\*[Am] 81.Pp 82This incantation would wait half an hour before 83running the script command_file. 84(See the 85.Xr at 1 86utility.) 87.Pp 88To reiteratively run a command (with 89.Xr csh 1 ) : 90.Pp 91.Bd -literal -offset indent -compact 92while (1) 93 if (! -r zzz.rawdata) then 94 sleep 300 95 else 96 foreach i (*.rawdata) 97 sleep 70 98 awk -f collapse_data $i \*[Gt]\*[Gt] results 99 end 100 break 101 endif 102end 103.Ed 104.Pp 105The scenario for a script such as this might be: a program currently 106running is taking longer than expected to process a series of 107files, and it would be nice to have 108another program start processing the files created by the first 109program as soon as it is finished (when zzz.rawdata is created). 110The script checks every five minutes for the file zzz.rawdata, 111when the file is found, then another portion processing 112is done courteously by sleeping for 70 seconds in between each 113awk job. 114.Sh SEE ALSO 115.Xr at 1 , 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 127utility appeared in 128.At v4 . 129