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2295cae7e6
Program: * Add a dummy getopt(3) loop to handle `--`. * Move interval parsing out into a separate function. * Print a diagnostic for every invalid interval. * Check for NaN and infinity. * Improve bounds checks. Manual page: * Miscellaneous markup fixes. * Reword DESCRIPTION section. * Move text about GNU compatibility to STANDARDS section. * Convert examples from csh to sh. Sponsored by: Klara, Inc. Reviewed by: kevans Differential Revision: https://reviews.freebsd.org/D44471
134 lines
3.9 KiB
Groff
134 lines
3.9 KiB
Groff
.\"-
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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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.Dd March 22, 2024
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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
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.Ar number Ns Op Ar unit
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.Op ...
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.Sh DESCRIPTION
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The
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.Nm
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command suspends execution for a minimum of
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.Ar number
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seconds (the default, or unit
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.Li s ) ,
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minutes (unit
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.Li m ) ,
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hours (unit
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.Li h ) ,
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or days (unit
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.Li d ) .
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Intervals can be written in any form allowed by
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.Xr strtod 3 .
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If multiple intervals are given, they are added together.
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If the final sum is zero or negative,
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.Nm
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exits immediately.
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.Pp
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If the
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.Nm
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command receives a signal, it takes the standard action.
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When the
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.Dv SIGINFO
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signal is received, the estimate of the amount of seconds left to
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sleep is printed on the standard output.
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.Sh IMPLEMENTATION NOTES
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The
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.Dv SIGALRM
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signal is not handled specially by this implementation.
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.Sh EXIT STATUS
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.Ex -std
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.Sh EXAMPLES
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To run a command after half an hour:
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.Pp
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.Dl (sleep 0.5h; sh command_file >out 2>err)&
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.Pp
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This incantation would wait half an hour before
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running the script
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.Pa command_file .
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See the
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.Xr at 1
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utility for another way to do this.
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.Pp
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To reiteratively run a command:
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.Pp
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.Bd -literal -offset indent -compact
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while :; do
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if ! [ -r zzz.rawdata ] ; then
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sleep 5m
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else
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for i in *.rawdata ; do
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sleep 70
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awk -f collapse_data "$i"
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done >results
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break
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fi
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done
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.Ed
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.Pp
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The scenario for a script such as this 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
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another program start processing the files created by the first
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program as soon as it is finished (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 the file
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.Pa zzz.rawdata ,
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when the file is found, then another portion processing
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is done courteously by sleeping for 70 seconds in between each
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.Xr awk 1
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job.
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.Sh SEE ALSO
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.Xr nanosleep 2 ,
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.Xr sleep 3
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.Sh STANDARDS
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The
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.Nm
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command is expected to be
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.St -p1003.2
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compatible.
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.Pp
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Support for non-integer intervals, units other than seconds, and
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multiple intervals which are added together are non-portable
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extensions first introduced in GNU sh-utils 2.0a (released in 2002).
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.Sh HISTORY
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A
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.Nm
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command appeared in
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.At v4 .
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