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.Dd March 22, 2024 33.Dt SLEEP 1 34.Os 35.Sh NAME 36.Nm sleep 37.Nd suspend execution for an interval of time 38.Sh SYNOPSIS 39.Nm 40.Ar number Ns Op Ar unit 41.Op ... 42.Sh DESCRIPTION 43The 44.Nm 45command suspends execution for a minimum of 46.Ar number 47seconds (the default, or unit 48.Li s ) , 49minutes (unit 50.Li m ) , 51hours (unit 52.Li h ) , 53or days (unit 54.Li d ) . 55Intervals can be written in any form allowed by 56.Xr strtod 3 . 57If multiple intervals are given, they are added together. 58If the final sum is zero or negative, 59.Nm 60exits immediately. 61.Pp 62If the 63.Nm 64command receives a signal, it takes the standard action. 65When the 66.Dv SIGINFO 67signal is received, the estimate of the amount of seconds left to 68sleep is printed on the standard output. 69.Sh IMPLEMENTATION NOTES 70The 71.Dv SIGALRM 72signal is not handled specially by this implementation. 73.Sh EXIT STATUS 74.Ex -std 75.Sh EXAMPLES 76To run a command after half an hour: 77.Pp 78.Dl (sleep 0.5h; sh command_file >out 2>err)& 79.Pp 80This incantation would wait half an hour before 81running the script 82.Pa command_file . 83See the 84.Xr at 1 85utility for another way to do this. 86.Pp 87To reiteratively run a command: 88.Pp 89.Bd -literal -offset indent -compact 90while :; do 91 if ! [ -r zzz.rawdata ] ; then 92 sleep 5m 93 else 94 for i in *.rawdata ; do 95 sleep 70 96 awk -f collapse_data "$i" 97 done >results 98 break 99 fi 100done 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 108.Pa zzz.rawdata 109is created). 110The script checks every five minutes for the file 111.Pa zzz.rawdata , 112when the file is found, then another portion processing 113is done courteously by sleeping for 70 seconds in between each 114.Xr awk 1 115job. 116.Sh SEE ALSO 117.Xr nanosleep 2 , 118.Xr sleep 3 119.Sh STANDARDS 120The 121.Nm 122command is expected to be 123.St -p1003.2 124compatible. 125.Pp 126Support for non-integer intervals, units other than seconds, and 127multiple intervals which are added together are non-portable 128extensions first introduced in GNU sh-utils 2.0a (released in 2002). 129.Sh HISTORY 130A 131.Nm 132command appeared in 133.At v4 . 134