118 lines
3.6 KiB
Groff
118 lines
3.6 KiB
Groff
.\" $OpenBSD: sleep.1,v 1.22 2016/08/16 18:51:25 schwarze Exp $
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.\" $NetBSD: sleep.1,v 1.9 1995/07/25 19:37:43 jtc Exp $
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.\"
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.\" Copyright (c) 1990, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the Institute of Electrical and Electronics Engineers, Inc.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94
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.\"
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.Dd $Mdocdate: August 16 2016 $
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.Dt SLEEP 1
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.Os
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.Sh NAME
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.Nm sleep
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.Nd suspend execution for an interval of time
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.Sh SYNOPSIS
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.Nm sleep
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.Ar seconds
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.Sh DESCRIPTION
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The
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.Nm
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utility
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suspends execution for a minimum of the specified number of
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.Ar seconds .
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This number must be positive and may contain a decimal fraction.
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.Nm
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is commonly used to schedule the execution of other commands (see below).
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.Sh ASYNCHRONOUS EVENTS
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.Bl -tag -width "SIGALRMXXX"
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.It Dv SIGALRM
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Terminate normally, with a zero exit status.
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.El
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.Sh EXIT STATUS
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.Ex -std sleep
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.Sh EXAMPLES
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Wait a half hour before running the script
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.Pa command_file
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(see also the
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.Xr at 1
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utility):
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.Pp
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.Dl (sleep 1800; sh command_file >& errors)&
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.Pp
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To repetitively run a command (with
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.Xr csh 1 ) :
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.Bd -literal -offset indent
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while (! -r zzz.rawdata)
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sleep 300
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end
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foreach i (*.rawdata)
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sleep 70
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awk -f collapse_data $i >> results
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end
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.Ed
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.Pp
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The scenario for such a script might be: a program currently
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running is taking longer than expected to process a series of
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files, and it would be nice to have another program start
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processing the files created by the first program as soon as it is finished
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(when
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.Pa zzz.rawdata
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is created).
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The script checks every five minutes for this file.
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When it is found, processing is done in several steps
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by sleeping 70 seconds between each
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.Xr awk 1
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job.
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.Pp
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To monitor the growth of a file without consuming too many resources:
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.Bd -literal -offset indent
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while true; do
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ls -l file
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sleep 5
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done
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.Ed
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.Sh SEE ALSO
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.Xr at 1
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.Sh STANDARDS
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The
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.Nm
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utility is compliant with the
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.St -p1003.1-2008
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specification.
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.Pp
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The handling of fractional arguments is provided as an extension to that
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specification.
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.Sh HISTORY
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A
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.Nm
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utility appeared in
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.At v4 .
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