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.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 36.\" $FreeBSD$ 37.\" 38.Dd April 18, 1994 39.Dt SLEEP 1 40.Os 41.Sh NAME 42.Nm sleep 43.Nd suspend execution for an interval of time 44.Sh SYNOPSIS 45.Nm 46.Ar seconds 47.Sh DESCRIPTION 48The 49.Nm 50command 51suspends execution for a minimum of 52.Ar seconds . 53.Pp 54If the 55.Nm 56command receives a signal, it takes the standard action. 57.Sh IMPLEMENTATION NOTES 58The 59.Dv SIGALRM 60signal is not handled specially by this implementation. 61.Pp 62The 63.Nm 64command will accept and honor a non-integer number of specified seconds 65.Po 66with a 67.Ql \&. 68character as a decimal point 69.Pc . 70.Bf Sy 71This is a non-portable extension, and its use will nearly guarantee that 72a shell script will not execute properly on another system. 73.Ef 74.Sh DIAGNOSTICS 75The 76.Nm 77utility exits with one of the following values: 78.Bl -tag -width flag 79.It Li \&0 80On successful completion. 81.It Li \&>\&0 82An error occurred. 83.El 84.Sh EXAMPLES 85To schedule the execution of a command for 86.Va x 87number seconds later: 88.Pp 89.Dl (sleep 1800; sh command_file >& errors)& 90.Pp 91This incantation would wait a half hour before 92running the script command_file. (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