1.\"- 2.\" Copyright (c) 1990, 1993, 1994 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" the Institute of Electrical and Electronics Engineers, Inc. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 33.\" $FreeBSD$ 34.\" 35.Dd May 24, 2022 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 number[unit] ... 44.Sh DESCRIPTION 45The 46.Nm 47command suspends execution for a minimum of 48.Ar number 49seconds (the default, or unit 50.Ar s ) , 51minutes (unit 52.Ar m ) , 53hours (unit 54.Ar h ) , 55or days (unit 56.Ar d ) . 57If multiple arguments are passed, the delay will be the sum of all values. 58.Pp 59If the 60.Nm 61command receives a signal, it takes the standard action. 62When the 63.Dv SIGINFO 64signal is received, the estimate of the amount of seconds left to 65sleep is printed on the standard output. 66.Sh IMPLEMENTATION NOTES 67The 68.Dv SIGALRM 69signal is not handled specially by this implementation. 70.Pp 71The 72.Nm 73command supports other time units than seconds, 74honors a non-integer number of time units to sleep in any form acceptable by 75.Xr strtod 3 , 76and accepts more than one delay value. 77These are non-portable extensions, but they have also been implemented 78in GNU sh-utils since version 2.0a (released in 2002). 79.Sh EXIT STATUS 80.Ex -std 81.Sh EXAMPLES 82To schedule the execution of a command for 83.Va x 84number seconds later (with 85.Xr csh 1 ) : 86.Pp 87.Dl (sleep 1800; sh command_file >& errors)& 88.Pp 89This incantation would wait a half hour before 90running the script command_file. 91(See the 92.Xr at 1 93utility.) 94.Pp 95To reiteratively run a command (with the 96.Xr csh 1 ) : 97.Pp 98.Bd -literal -offset indent -compact 99while (1) 100 if (! -r zzz.rawdata) then 101 sleep 300 102 else 103 foreach i (`ls *.rawdata`) 104 sleep 70 105 awk -f collapse_data $i >> results 106 end 107 break 108 endif 109end 110.Ed 111.Pp 112The scenario for a script such as this might be: a program currently 113running is taking longer than expected to process a series of 114files, and it would be nice to have 115another program start processing the files created by the first 116program as soon as it is finished (when zzz.rawdata is created). 117The script checks every five minutes for the file zzz.rawdata, 118when the file is found, then another portion processing 119is done courteously by sleeping for 70 seconds in between each 120awk job. 121.Sh SEE ALSO 122.Xr nanosleep 2 , 123.Xr sleep 3 124.Sh STANDARDS 125The 126.Nm 127command is expected to be 128.St -p1003.2 129compatible. 130.Sh HISTORY 131A 132.Nm 133command appeared in 134.At v4 . 135