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. 93(See the 94.Xr at 1 95utility.) 96.Pp 97To reiteratively run a command (with the 98.Xr csh 1 ) : 99.Pp 100.Bd -literal -offset indent -compact 101while (1) 102 if (! -r zzz.rawdata) then 103 sleep 300 104 else 105 foreach i (`ls *.rawdata`) 106 sleep 70 107 awk -f collapse_data $i >> results 108 end 109 break 110 endif 111end 112.Ed 113.Pp 114The scenario for a script such as this might be: a program currently 115running is taking longer than expected to process a series of 116files, and it would be nice to have 117another program start processing the files created by the first 118program as soon as it is finished (when zzz.rawdata is created). 119The script checks every five minutes for the file zzz.rawdata, 120when the file is found, then another portion processing 121is done courteously by sleeping for 70 seconds in between each 122awk job. 123.Sh SEE ALSO 124.Xr nanosleep 2 , 125.Xr sleep 3 126.Sh STANDARDS 127The 128.Nm 129command is expected to be 130.St -p1003.2 131compatible. 132