xref: /freebsd/usr.bin/random/random.6 (revision bdcbfde31e8e9b343f113a1956384bdf30d1ed62)

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.Dd February 15, 2020
.Dt RANDOM 6
.Os
.Sh NAME
.Nm random
.Nd random lines from a file or random numbers
.Sh SYNOPSIS
.Nm
.Op Fl elrUuw
.Op Fl f Ar filename
.Op Ar denominator
.Sh DESCRIPTION
.Nm Random
has two distinct modes of operations.
The default is to read lines from standard input and write them to standard
output with a probability of 1.0 /
.Ar denominator .
.Ar ( denominator
is a real number greater than or equal to 1.0.)
The default
.Ar denominator
for this mode of operation is 2.0, giving each line a 50% chance of
being displayed.
.Pp
The second mode of operation, selected with the
.Fl f Ar filename
option, reads the specified file and outputs the randomized contents to
standard output.
The contents can be randomized in units of lines (split on newline characters)
or in units of words (split on space characters as determined by
.Xr isspace 3 . )
The default
.Ar denominator
for this mode of operation is 1.0, which displays every line.
.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.
In this mode,
.Ar denominator
must be less than or equal to 256.
.It Fl f Ar filename
The
.Fl f
option is used to specify the
.Ar filename
to read from.
Standard input is used if
.Ar filename
is
.Sq - .
.It Fl l
Randomize the input via newlines (the default).
.It Fl r
Do not buffer output.
.It Fl U
Reuse any given line or word when creating a randomized output.
.It Fl u
Do not 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 in the input.
.It Fl w
Randomize words separated by
.Xr isspace 3
instead of newlines.
.El
.Sh SEE ALSO
.Xr fortune 6
.Sh HISTORY
The
functionality to randomizing lines and words was added in 2003 by
.An Sean Chittenden Aq Mt seanc@FreeBSD.org .
.Sh BUGS
This tool is a remnant of the "games" collection formerly part of
.Fx
base.
It probably should have been removed to ports with the rest of that collection.
It does not have a coherent purpose and the motivation for it to be a core base
utility is nonobvious.
.Pp
No index is used when printing out tokens from the list which
makes it rather slow for large files (10MB+).