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.\" 34.Dd December 31, 2020 35.Dt SLEEP 1 36.Os 37.Sh NAME 38.Nm sleep 39.Nd suspend execution for an interval of time 40.Sh SYNOPSIS 41.Nm 42.Ar seconds 43.Sh DESCRIPTION 44The 45.Nm 46command 47suspends execution for a minimum of 48.Ar seconds . 49.Pp 50If the 51.Nm 52command receives a signal, it takes the standard action. 53When the 54.Dv SIGINFO 55signal is received, the estimate of the amount of seconds left to 56sleep is printed on the standard output. 57.Sh IMPLEMENTATION NOTES 58The 59.Dv SIGALRM 60signal is not handled specially by this implementation. 61.Pp 62The 63.Nm 64command allows and honors a non-integer number of seconds to sleep 65in any form acceptable by 66.Xr strtod 3 . 67This is a non-portable extension, but is also implemented in GNU sh-utils 68since version 2.0a (released in 2002). 69.Sh EXIT STATUS 70.Ex -std 71.Sh EXAMPLES 72To schedule the execution of a command for 73.Va x 74number seconds later (with 75.Xr csh 1 ) : 76.Pp 77.Dl (sleep 1800; sh command_file >& errors)& 78.Pp 79This incantation would wait a half hour before 80running the script command_file. 81(See the 82.Xr at 1 83utility.) 84.Pp 85To reiteratively run a command (with the 86.Xr csh 1 ) : 87.Pp 88.Bd -literal -offset indent -compact 89while (1) 90 if (! -r zzz.rawdata) then 91 sleep 300 92 else 93 foreach i (`ls *.rawdata`) 94 sleep 70 95 awk -f collapse_data $i >> results 96 end 97 break 98 endif 99end 100.Ed 101.Pp 102The scenario for a script such as this might be: a program currently 103running is taking longer than expected to process a series of 104files, and it would be nice to have 105another program start processing the files created by the first 106program as soon as it is finished (when zzz.rawdata is created). 107The script checks every five minutes for the file zzz.rawdata, 108when the file is found, then another portion processing 109is done courteously by sleeping for 70 seconds in between each 110awk job. 111.Sh SEE ALSO 112.Xr nanosleep 2 , 113.Xr sleep 3 114.Sh STANDARDS 115The 116.Nm 117command is expected to be 118.St -p1003.2 119compatible. 120.Sh HISTORY 121A 122.Nm 123command appeared in 124.At v4 . 125