106 lines
3.2 KiB
Groff
106 lines
3.2 KiB
Groff
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.\" $NetBSD: shuffle.1,v 1.1 1998/09/23 21:05:59 perry Exp $
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.\"
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.\" Copyright (c) 1998
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.\" Perry E. Metzger. All rights reserved.
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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. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgment:
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.\" This product includes software developed for the NetBSD Project
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.\" by Perry E. Metzger.
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\"
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.Dd September 22, 1998
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.Dt SHUFFLE 1
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.Os
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.Sh NAME
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.Nm shuffle
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.Nd print a random permutation of the command line arguments
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.Sh SYNOPSIS
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.Nm
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.Op Fl c Ar arg ...
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.Op Fl n Ar number
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.Op Fl p Ar number
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.Op Ar file
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.Sh DESCRIPTION
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The
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.Nm
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program prints a random permutation (or
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.Dq shuffle )
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of its input lines. This can be useful in shell scripts for selecting a
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random order in which to do a set of tasks, view a set of files, etc.
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.Pp
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If a file name is given as an argument, the file is opened and used as input.
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.Pp
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If the
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.Fl c
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option is given, the rest of the arguments on the command line are
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shuffled, rather than standard input.
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.Pp
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If the
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.Fl n
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option is given, its argument is treated as a number, and the program
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prints a random permutation of the numbers greater than or equal to 0
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and less than the argument.
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.Pp
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If the
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.Fl p
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option is given, its argument is treated as a number, and the program
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prints that number of randomly selected lines or arguments in a random order.
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.Sh EXAMPLES
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.Bd -literal -offset indent
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$ shuffle -c a b c d
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c
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b
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d
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a
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$ shuffle -c a b c d
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d
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b
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a
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c
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$ shuffle -n 4
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0
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2
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1
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3
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.Ed
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.Sh SEE ALSO
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.Xr jot 1
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.Sh HISTORY
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The
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.Nm
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program first appeared in
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.Nx 1.4 .
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.Sh AUTHORS
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Written by Perry E. Metzger (perry@piermont.com).
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.Sh BUGS
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The random number generator isn't that great, and thus the
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permutations often aren't that great.
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.Pp
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The maximum size of an input line is limited to
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.Dv BUFSIZ
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from
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.Pa Aq stdio.h .
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Failures on longer lines are not likely to be pretty.
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