1.\" Copyright (c) 1990, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 32.\" $FreeBSD$ 33.\" 34.Dd April 18, 1994 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. 53.Sh IMPLEMENTATION NOTES 54The 55.Dv SIGALRM 56signal is not handled specially by this implementation. 57.Pp 58The 59.Nm 60command will accept and honor a non-integer number of specified seconds 61(with a 62.Ql .\& 63character as a decimal point). 64.Bf Sy 65This is a non-portable extension, and its use will nearly guarantee that 66a shell script will not execute properly on another system. 67.Ef 68.Sh EXAMPLES 69To schedule the execution of a command for 70.Va x 71number seconds later (with 72.Xr csh 1 ) : 73.Pp 74.Dl (sleep 1800; sh command_file >& errors)& 75.Pp 76This incantation would wait a half hour before 77running the script command_file. 78(See the 79.Xr at 1 80utility.) 81.Pp 82To reiteratively run a command (with the 83.Xr csh 1 ) : 84.Pp 85.Bd -literal -offset indent -compact 86while (1) 87 if (! -r zzz.rawdata) then 88 sleep 300 89 else 90 foreach i (`ls *.rawdata`) 91 sleep 70 92 awk -f collapse_data $i >> results 93 end 94 break 95 endif 96end 97.Ed 98.Pp 99The scenario for a script such as this might be: a program currently 100running is taking longer than expected to process a series of 101files, and it would be nice to have 102another program start processing the files created by the first 103program as soon as it is finished (when zzz.rawdata is created). 104The script checks every five minutes for the file zzz.rawdata, 105when the file is found, then another portion processing 106is done courteously by sleeping for 70 seconds in between each 107awk job. 108.Sh DIAGNOSTICS 109.Ex -std 110.Sh SEE ALSO 111.Xr nanosleep 2 , 112.Xr sleep 3 113.Sh STANDARDS 114The 115.Nm 116command is expected to be 117.St -p1003.2 118compatible. 119.Sh HISTORY 120A 121.Nm 122command appeared in 123.At v4 . 124