1.\" $NetBSD: shuffle.1,v 1.8 2009/02/19 10:08:15 wiz Exp $ 2.\" 3.\" Copyright (c) 1998 4.\" Perry E. Metzger. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgment: 16.\" This product includes software developed for the NetBSD Project 17.\" by Perry E. Metzger. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.\" 33.Dd February 18, 2009 34.Dt SHUFFLE 1 35.Os 36.Sh NAME 37.Nm shuffle 38.Nd print a random permutation of the command line arguments 39.Sh SYNOPSIS 40.Nm 41.Op Fl 0 42.Op Fl f Ar filename ... 43.Op Fl n Ar number 44.Op Fl p Ar number 45.Op Ar arg 46.Op Ar ... 47.Sh DESCRIPTION 48The 49.Nm 50program prints a random permutation (or 51.Dq shuffle ) 52of its command line arguments. 53This can be useful in shell scripts for selecting a 54random order in which to do a set of tasks, view a set of files, etc. 55.Pp 56If the 57.Fl f 58option is given, the data is taken from that files' contents or if the 59filename is 60.Ar - 61.Dq stdin . 62.Pp 63If the 64.Fl n 65option is given, its argument is treated as a number, and the program 66prints a random permutation of the numbers greater than or equal to 0 67and less than the argument. 68.Pp 69If the 70.Fl p 71option is given, its argument is treated as a number, and the program 72prints that number of randomly selected lines or arguments in a random order. 73.Pp 74The 75.Fl 0 76option changes the field separator character from \en to \e0, so that 77the output is suitable to be sent to 78.Xr xargs 1 79(to handle filenames with whitespace in them). 80.Sh EXAMPLES 81.Bd -literal -offset indent 82$ shuffle a b c d 83c 84b 85d 86a 87$ shuffle -p 1 a b c d 88d 89$ shuffle -n 4 -p 2 900 913 92.Ed 93.Sh SEE ALSO 94.Xr jot 1 , 95.Xr random 6 96.Sh HISTORY 97The 98.Nm 99program first appeared in 100.Nx 1.4 . 101.Sh AUTHORS 102Written by 103.An Perry E. Metzger 104.Aq perry@piermont.com . 105