xref: /freebsd/usr.bin/random/random.6 (revision a2f733abcff64628b7771a47089628b7327a88bd)
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28.Dd February 15, 2020
29.Dt RANDOM 6
30.Os
31.Sh NAME
32.Nm random
33.Nd random lines from a file or random numbers
34.Sh SYNOPSIS
35.Nm
36.Op Fl elrUuw
37.Op Fl f Ar filename
38.Op Ar denominator
39.Sh DESCRIPTION
40.Nm Random
41has two distinct modes of operations.
42The default is to read lines from standard input and write them to standard
43output with a probability of 1.0 /
44.Ar denominator .
45.Ar ( denominator
46is a real number greater than or equal to 1.0.)
47The default
48.Ar denominator
49for this mode of operation is 2.0, giving each line a 50% chance of
50being displayed.
51.Pp
52The second mode of operation, selected with the
53.Fl f Ar filename
54option, reads the specified file and outputs the randomized contents to
55standard output.
56The contents can be randomized in units of lines (split on newline characters)
57or in units of words (split on space characters as determined by
58.Xr isspace 3 . )
59The default
60.Ar denominator
61for this mode of operation is 1.0, which displays every line.
62.Pp
63The options are as follows:
64.Bl -tag -width Ds
65.It Fl e
66If the
67.Fl e
68option is specified,
69.Nm
70does not read or write anything, and simply exits with a random
71exit value of 0 to
72.Ar denominator
73\&- 1, inclusive.
74In this mode,
75.Ar denominator
76must be less than or equal to 256.
77.It Fl f Ar filename
78The
79.Fl f
80option is used to specify the
81.Ar filename
82to read from.
83Standard input is used if
84.Ar filename
85is
86.Sq - .
87.It Fl l
88Randomize the input via newlines (the default).
89.It Fl r
90Do not buffer output.
91.It Fl U
92Reuse any given line or word when creating a randomized output.
93.It Fl u
94Do not select the same line or word from a file more than once (the default).
95This does not guarantee uniqueness if there are two of the
96same tokens in the input.
97.It Fl w
98Randomize words separated by
99.Xr isspace 3
100instead of newlines.
101.El
102.Sh SEE ALSO
103.Xr fortune 6
104.Sh HISTORY
105The
106functionality to randomizing lines and words was added in 2003 by
107.An Sean Chittenden Aq Mt seanc@FreeBSD.org .
108.Sh BUGS
109This tool is a remnant of the "games" collection formerly part of
110.Fx
111base.
112It probably should have been removed to ports with the rest of that collection.
113It does not have a coherent purpose and the motivation for it to be a core base
114utility is nonobvious.
115.Pp
116No index is used when printing out tokens from the list which
117makes it rather slow for large files (10MB+).
118