Merge branch 'vendor/GCC50'
[dragonfly.git] / bin / sleep / sleep.1
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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.
dc71b7ab 15.\" 3. Neither the name of the University nor the names of its contributors
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16.\" may be used to endorse or promote products derived from this software
17.\" without specific prior written permission.
18.\"
19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29.\" SUCH DAMAGE.
30.\"
31.\" @(#)sleep.1 8.3 (Berkeley) 4/18/94
32.\" $FreeBSD: src/bin/sleep/sleep.1,v 1.15.2.3 2003/01/24 02:44:43 keramida Exp $
1de703da 33.\" $DragonFly: src/bin/sleep/sleep.1,v 1.2 2003/06/17 04:22:50 dillon Exp $
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34.\"
35.Dd April 18, 1994
36.Dt SLEEP 1
37.Os
38.Sh NAME
39.Nm sleep
40.Nd suspend execution for an interval of time
41.Sh SYNOPSIS
42.Nm
43.Ar seconds
44.Sh DESCRIPTION
45The
46.Nm
47command
48suspends execution for a minimum of
49.Ar seconds .
50.Pp
51If the
52.Nm
53command receives a signal, it takes the standard action.
54.Sh IMPLEMENTATION NOTES
55The
56.Dv SIGALRM
57signal is not handled specially by this implementation.
58.Pp
59The
60.Nm
61command will accept and honor a non-integer number of specified seconds
62(with a
63.Ql .\&
64character as a decimal point).
65.Bf Sy
66This is a non-portable extension, and its use will nearly guarantee that
67a shell script will not execute properly on another system.
68.Ef
19fe1c42
SW
69.Sh EXIT STATUS
70.Ex -std
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71.Sh EXAMPLES
72To schedule the execution of a command for
73.Va x
74number seconds later (with
75.Xr csh 1 ) :
76.Pp
77.Dl (sleep 1800; sh command_file >& errors)&
78.Pp
79This incantation would wait a half hour before
80running the script command_file.
81(See the
82.Xr at 1
83utility.)
84.Pp
85To reiteratively run a command (with the
86.Xr csh 1 ) :
87.Pp
88.Bd -literal -offset indent -compact
89while (1)
90 if (! -r zzz.rawdata) then
91 sleep 300
92 else
93 foreach i (`ls *.rawdata`)
94 sleep 70
95 awk -f collapse_data $i >> results
96 end
97 break
98 endif
99end
100.Ed
101.Pp
102The scenario for a script such as this might be: a program currently
103running is taking longer than expected to process a series of
104files, and it would be nice to have
105another program start processing the files created by the first
106program as soon as it is finished (when zzz.rawdata is created).
107The script checks every five minutes for the file zzz.rawdata,
108when the file is found, then another portion processing
109is done courteously by sleeping for 70 seconds in between each
110awk job.
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111.Sh SEE ALSO
112.Xr nanosleep 2 ,
113.Xr sleep 3
114.Sh STANDARDS
115The
116.Nm
117command is expected to be
118.St -p1003.2
119compatible.
120.Sh HISTORY
121A
122.Nm
123command appeared in
124.At v4 .