.\"	$NetBSD: shuffle.1,v 1.8 2009/02/19 10:08:15 wiz Exp $
.\"
.\" Copyright (c) 1998
.\" 	Perry E. Metzger.  All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\"    must display the following acknowledgment:
.\"	This product includes software developed for the NetBSD Project
.\"	by Perry E. Metzger.
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.Dd February 18, 2009
.Dt SHUFFLE 1
.Os
.Sh NAME
.Nm shuffle
.Nd print a random permutation of the command line arguments
.Sh SYNOPSIS
.Nm
.Op Fl 0
.Op Fl f Ar filename ...
.Op Fl n Ar number
.Op Fl p Ar number
.Op Ar arg
.Op Ar ...
.Sh DESCRIPTION
The
.Nm
program prints a random permutation (or
.Dq shuffle )
of its command line arguments.
This can be useful in shell scripts for selecting a
random order in which to do a set of tasks, view a set of files, etc.
.Pp
If the
.Fl f
option is given, the data is taken from that files' contents or if the
filename is
.Ar -
.Dq stdin .
.Pp
If the
.Fl n
option is given, its argument is treated as a number, and the program
prints a random permutation of the numbers greater than or equal to 0
and less than the argument.
.Pp
If the
.Fl p
option is given, its argument is treated as a number, and the program
prints that number of randomly selected lines or arguments in a random order.
.Pp
The
.Fl 0
option changes the field separator character from \en to \e0, so that
the output is suitable to be sent to
.Xr xargs 1
(to handle filenames with whitespace in them).
.Sh EXAMPLES
.Bd -literal -offset indent
$ shuffle a b c d
c
b
d
a
$ shuffle -p 1 a b c d
d
$ shuffle -n 4 -p 2
0
3
.Ed
.Sh SEE ALSO
.Xr jot 1 ,
.Xr random 6
.Sh HISTORY
The
.Nm
program first appeared in
.Nx 1.4 .
.Sh AUTHORS
Written by
.An Perry E. Metzger
.Aq perry@piermont.com .