freebsd-dev/games/random/random.6

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.\"     @(#)random.6	8.2 (Berkeley) 3/31/94
.\" $FreeBSD$
.\"
.Dd February 8, 2003
.Dt RANDOM 6
.Os
.Sh NAME
.Nm random
.Nd random lines from a file or random numbers
.Sh SYNOPSIS
.Nm
.Op Fl er
.Op Fl f Ar filename
.Op Ar denominator
.Sh DESCRIPTION
.Nm Random
has two distinct modes of operations.  The default is to read in lines
from stdin and randomly write them out to stdout with a probability of
1 /
.Ar denominator .
The default
.Ar denominator
for this mode of operation is 2, giving each line a 50/50 chance of
being displayed.
.Pp
The second mode of operation is to read in a file from
.Ar filename
and randomize the contents of the file and send it back out to stdout.
The contents can be randomized based off of newlines or based off of
space characters as determined by
.Xr isspace 3 .
The default
.Ar denominator
for this mode of operation is 1, which gives each line a chance to be
displayed, but in a
.Xr random 3
order.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl e
If the
.Fl e
option is specified,
.Nm
does not read or write anything, and simply exits with a random
exit value of 0 to
.Ar denominator
\&- 1, inclusive.
.It Fl f Ar filename
The
.Fl f
option is used to specify the
.Ar filename
to read from.  stdin is used if the filename is set to "-".
.It Fl l
Randomize the input via newlines (the default).
.It Fl r
The
.Fl r
option guarantees that the output is unbuffered.
.It Fl u
Tells
.Xr random 6
not to select the same line or word from a file more than once (the
default).  This does not guarantee uniqueness if there are two of the
same tokens from the input, but it does prevent selecting the same
token more than once.
.It Fl U
Tells
.Xr random 6
that it is okay for it to reuse any given line or word when creating a
randomized output.
.It Fl w
Randomize words separated by
.Xr isspace 3
instead of newlines.
.El
.Sh SEE ALSO
.Xr fortune 6 ,
.Xr random 3
.Sh BUGS
There is no index used when printing out tokens from the list which
makes rather slow for large files (10MB+).  If this were used in
performance sensitive areas, I'd do something about it.  For smaller
files, however, it should still be quite fast and efficient.
.Sh HISTORY
Original
.Xr random 6
game was brought in from BSD 4.4 Lite by jkh in 1994.  The
functionality to randomizing lines and words was added in 2003 by
seanc.