xref: /freebsd/usr.bin/random/random.6 (revision 90aad5d3e44d137ce80d2ec257de07c7c1367bd3)
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28.\"     @(#)random.6	8.2 (Berkeley) 3/31/94
29.\"
30.Dd February 15, 2020
31.Dt RANDOM 6
32.Os
33.Sh NAME
34.Nm random
35.Nd random lines from a file or random numbers
36.Sh SYNOPSIS
37.Nm
38.Op Fl elrUuw
39.Op Fl f Ar filename
40.Op Ar denominator
41.Sh DESCRIPTION
42.Nm Random
43has two distinct modes of operations.
44The default is to read lines from standard input and write them to standard
45output with a probability of 1.0 /
46.Ar denominator .
47.Ar ( denominator
48is a real number greater than or equal to 1.0.)
49The default
50.Ar denominator
51for this mode of operation is 2.0, giving each line a 50% chance of
52being displayed.
53.Pp
54The second mode of operation, selected with the
55.Fl f Ar filename
56option, reads the specified file and outputs the randomized contents to
57standard output.
58The contents can be randomized in units of lines (split on newline characters)
59or in units of words (split on space characters as determined by
60.Xr isspace 3 . )
61The default
62.Ar denominator
63for this mode of operation is 1.0, which displays every line.
64.Pp
65The options are as follows:
66.Bl -tag -width Ds
67.It Fl e
68If the
69.Fl e
70option is specified,
71.Nm
72does not read or write anything, and simply exits with a random
73exit value of 0 to
74.Ar denominator
75\&- 1, inclusive.
76In this mode,
77.Ar denominator
78must be less than or equal to 256.
79.It Fl f Ar filename
80The
81.Fl f
82option is used to specify the
83.Ar filename
84to read from.
85Standard input is used if
86.Ar filename
87is
88.Sq - .
89.It Fl l
90Randomize the input via newlines (the default).
91.It Fl r
92Do not buffer output.
93.It Fl U
94Reuse any given line or word when creating a randomized output.
95.It Fl u
96Do not select the same line or word from a file more than once (the default).
97This does not guarantee uniqueness if there are two of the
98same tokens in the input.
99.It Fl w
100Randomize words separated by
101.Xr isspace 3
102instead of newlines.
103.El
104.Sh SEE ALSO
105.Xr fortune 6
106.Sh HISTORY
107The
108functionality to randomizing lines and words was added in 2003 by
109.An Sean Chittenden Aq Mt seanc@FreeBSD.org .
110.Sh BUGS
111This tool is a remnant of the "games" collection formerly part of
112.Fx
113base.
114It probably should have been removed to ports with the rest of that collection.
115It does not have a coherent purpose and the motivation for it to be a core base
116utility is nonobvious.
117.Pp
118No index is used when printing out tokens from the list which
119makes it rather slow for large files (10MB+).
120