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.\" %sccs.include.redist.roff% 8.\" 9.\" @(#)sleep.1 8.3 (Berkeley) 04/18/94 10.\" 11.Dd 12.Dt SLEEP 1 13.Os 14.Sh NAME 15.Nm sleep 16.Nd suspend execution for an interval of time 17.Sh SYNOPSIS 18.Nm sleep 19.Ar seconds 20.Sh DESCRIPTION 21The 22.Nm sleep 23command 24suspends execution for a minimum of 25.Ar seconds . 26.Nm Sleep 27is used to schedule the execution of other commands (see 28.Sx EXAMPLES 29below). 30.Pp 31The 32.Nm Sleep 33utility exits with one of the following values: 34.Bl -tag -width flag 35.It Li \&0 36On successful completion, or if the signal 37.Dv SIGALRM 38was received. 39.It Li \&>\&0 40An error occurred. 41.El 42.Sh EXAMPLES 43To schedule the execution of a command for 44.Va x 45number seconds later: 46.Pp 47.Dl (sleep 1800; sh command_file >& errors)& 48.Pp 49This incantation would wait a half hour before 50running the script command_file. (See the 51.Xr at 1 52utility.) 53.Pp 54To reiteratively run a command (with the 55.Xr csh 1 ) : 56.Pp 57.Bd -literal -offset indent -compact 58while (1) 59 if (! -r zzz.rawdata) then 60 sleep 300 61 else 62 foreach i (`ls *.rawdata`) 63 sleep 70 64 awk -f collapse_data $i >> results 65 end 66 break 67 endif 68end 69.Ed 70.Pp 71The scenario for a script such as this might be: a program currently 72running is taking longer than expected to process a series of 73files, and it would be nice to have 74another program start processing the files created by the first 75program as soon as it is finished (when zzz.rawdata is created). 76The script checks every five minutes for the file zzz.rawdata, 77when the file is found, then another portion processing 78is done courteously by sleeping for 70 seconds in between each 79awk job. 80.Sh SEE ALSO 81.Xr setitimer 2 , 82.Xr alarm 3 , 83.Xr sleep 3 , 84.Xr at 1 85.Sh STANDARDS 86The 87.Nm sleep 88command is expected to be 89.St -p1003.2 90compatible. 91