.\" $NetBSD: sleep.1,v 1.11 1997/09/14 07:31:56 lukem Exp $ .\" .\" Copyright (c) 1990, 1993, 1994 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" the Institute of Electrical and Electronics Engineers, Inc. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)sleep.1 8.3 (Berkeley) 4/18/94 .\" .Dd April 18, 1994 .Dt SLEEP 1 .Os .Sh NAME .Nm sleep .Nd suspend execution for an interval of time .Sh SYNOPSIS .Nm .Ar seconds .Sh DESCRIPTION The .Nm utility suspends execution for a minimum of .Ar seconds . It is usually used to schedule the execution of other commands (see .Sx EXAMPLES below). .Pp The .Nm utility exits with one of the following values: .Bl -tag -width flag .It Li \&0 On successful completion, or if the signal .Dv SIGALRM was received. .It Li \&>\&0 An error occurred. .El .Pp Note: The .Nx .Nm command will accept and honor a non-integer number of specified seconds. This is a non-portable extension, and its use will nearly guarantee that a shell script will not execute properly on another system. .Sh EXAMPLES To schedule the execution of a command for .Va x number seconds later: .Pp .Dl (sleep 1800; sh command_file >& errors)& .Pp This incantation would wait a half hour before running the script command_file. (See the .Xr at 1 utility.) .Pp To reiteratively run a command (with the .Xr csh 1 ) : .Pp .Bd -literal -offset indent -compact while (1) if (! -r zzz.rawdata) then sleep 300 else foreach i (`ls *.rawdata`) sleep 70 awk -f collapse_data $i >> results end break endif end .Ed .Pp The scenario for a script such as this might be: a program currently running is taking longer than expected to process a series of files, and it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata is created). The script checks every five minutes for the file zzz.rawdata, when the file is found, then another portion processing is done courteously by sleeping for 70 seconds in between each awk job. .Sh SEE ALSO .Xr nanosleep 2 , .Xr sleep 3 , .Xr at 1 .Sh STANDARDS The .Nm command is expected to be .St -p1003.2 compatible.