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 25, 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 Ns Op Ar unit 44.Ar ... 45.Sh DESCRIPTION 46The 47.Nm 48command suspends execution for a minimum of 49.Ar number 50seconds (the default, or unit 51.Cm s ) , 52minutes (unit 53.Cm m ) , 54hours (unit 55.Cm h ) , 56or days (unit 57.Cm d ) . 58If multiple arguments are passed, the delay will be the sum of all values. 59.Pp 60If the 61.Nm 62command receives a signal, it takes the standard action. 63When the 64.Dv SIGINFO 65signal is received, the estimate of the amount of seconds left to 66sleep is printed on the standard output. 67.Sh IMPLEMENTATION NOTES 68The 69.Dv SIGALRM 70signal is not handled specially by this implementation. 71.Pp 72The 73.Nm 74command supports other time units than seconds, 75honors a non-integer number of time units to sleep in any form acceptable by 76.Xr strtod 3 , 77and accepts more than one delay value. 78These are non-portable extensions, but they have also been implemented 79in GNU sh-utils since version 2.0a (released in 2002). 80.Sh EXIT STATUS 81.Ex -std 82.Sh EXAMPLES 83To schedule the execution of a command for 84.Va x 85number seconds later (with 86.Xr csh 1 ) : 87.Pp 88.Dl (sleep 1800; sh command_file >& errors)& 89.Pp 90This incantation would wait a half hour before 91running the script command_file. 92(See the 93.Xr at 1 94utility.) 95.Pp 96To reiteratively run a command (with the 97.Xr csh 1 ) : 98.Pp 99.Bd -literal -offset indent -compact 100while (1) 101 if (! -r zzz.rawdata) then 102 sleep 300 103 else 104 foreach i (`ls *.rawdata`) 105 sleep 70 106 awk -f collapse_data $i >> results 107 end 108 break 109 endif 110end 111.Ed 112.Pp 113The scenario for a script such as this might be: a program currently 114running is taking longer than expected to process a series of 115files, and it would be nice to have 116another program start processing the files created by the first 117program as soon as it is finished (when zzz.rawdata is created). 118The script checks every five minutes for the file zzz.rawdata, 119when the file is found, then another portion processing 120is done courteously by sleeping for 70 seconds in between each 121awk job. 122.Sh SEE ALSO 123.Xr nanosleep 2 , 124.Xr sleep 3 125.Sh STANDARDS 126The 127.Nm 128command is expected to be 129.St -p1003.2 130compatible. 131.Sh HISTORY 132A 133.Nm 134command appeared in 135.At v4 . 136