1.\" Copyright (c) 1990 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)sleep.1 6.3 (Berkeley) 07/24/90 7.\" 8.Dd 9.Dt SLEEP 1 10.Os BSD 4.4 11.Sh NAME 12.Nm sleep 13.Nd suspend execution for an interval of time 14.Sh SYNOPSIS 15.Nm sleep 16.Ar seconds 17.Sh DESCRIPTION 18The 19.Nm sleep 20command 21suspends execution for a minimum of 22.Ar seconds . 23.Nm Sleep 24is used to schedule the execution of other commands (see 25EXAMPLES below). 26.Pp 27The 28.Nm Sleep 29utility exits with one of the following values: 30.Tw Ds 31.Tp Li \&0 32On successful completetion, or if the signal SIGALRM was received. 33.Tp Li \&>\&0 34An error occurred. 35.Tp 36.Sh EXAMPLES 37To schedule the execution of a command for 38.Va x 39number seconds later: 40.Pp 41.Dl (sleep 1800; sh command_file >& errors)& 42.Pp 43This incantation would wait a half hour before 44running the script command_file. (See the 45.Xr at 1 46utility.) 47.Pp 48To reiteratively run a command (with the 49.Xr csh 1 ) : 50.Pp 51.Ds I 52while (1) 53 if (! -r zzz.rawdata) then 54 sleep 300 55 else 56 foreach i (`ls *.rawdata`) 57 sleep 70 58 awk -f collapse_data $i >> results 59 end 60 break 61 endif 62end 63.De 64.Pp 65The scenario for a script such as this might be: a program currently 66running is taking longer than expected to process a series of 67files, and it would be nice to have 68another program start processing the files created by the first 69program as soon as it is finished (when zzz.rawdata is created). 70The script checks every five minutes for the file zzz.rawdata, 71when the file is found, then another portion processing 72is done curteously by sleeping for 70 seconds in between each 73awk job. 74.Sh SEE ALSO 75.Xr setitimer 2 , 76.Xr alarm 3 , 77.Xr sleep 3 , 78.Xr at 1 79.Sh STANDARDS 80The sleep function is expected to be POSIX 1003.2 compatible. 81