xref: /freebsd/usr.bin/random/random.6 (revision 49b49cda41feabe3439f7318e8bf40e3896c7bf4)
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28.\"     @(#)random.6	8.2 (Berkeley) 3/31/94
29.\" $FreeBSD$
30.\"
31.Dd February 8, 2003
32.Dt RANDOM 6
33.Os
34.Sh NAME
35.Nm random
36.Nd random lines from a file or random numbers
37.Sh SYNOPSIS
38.Nm
39.Op Fl elrUuw
40.Op Fl f Ar filename
41.Op Ar denominator
42.Sh DESCRIPTION
43.Nm Random
44has two distinct modes of operations.
45The default is to read in lines
46from the standard input and randomly write them out
47to the standard output with a probability of
481 /
49.Ar denominator .
50The default
51.Ar denominator
52for this mode of operation is 2, giving each line a 50/50 chance of
53being displayed.
54.Pp
55The second mode of operation is to read in a file from
56.Ar filename
57and randomize the contents of the file and send it back out to
58standard output.
59The contents can be randomized based off of newlines or based off of
60space characters as determined by
61.Xr isspace 3 .
62The default
63.Ar denominator
64for this mode of operation is 1, which gives each line a chance to be
65displayed, but in a
66.Xr random 3
67order.
68.Pp
69The options are as follows:
70.Bl -tag -width Ds
71.It Fl e
72If the
73.Fl e
74option is specified,
75.Nm
76does not read or write anything, and simply exits with a random
77exit value of 0 to
78.Ar denominator
79\&- 1, inclusive.
80.It Fl f Ar filename
81The
82.Fl f
83option is used to specify the
84.Ar filename
85to read from.
86Standard input is used if
87.Ar filename
88is set to
89.Sq Fl .
90.It Fl l
91Randomize the input via newlines (the default).
92.It Fl r
93The
94.Fl r
95option guarantees that the output is unbuffered.
96.It Fl U
97Tells
98.Xr random 6
99that it is okay for it to reuse any given line or word when creating a
100randomized output.
101.It Fl u
102Tells
103.Xr random 6
104not to select the same line or word from a file more than once (the
105default).
106This does not guarantee uniqueness if there are two of the
107same tokens from the input, but it does prevent selecting the same
108token more than once.
109.It Fl w
110Randomize words separated by
111.Xr isspace 3
112instead of newlines.
113.El
114.Sh SEE ALSO
115.Xr random 3 ,
116.Xr fortune 6
117.Sh HISTORY
118The
119functionality to randomizing lines and words was added in 2003 by
120.An Sean Chittenden Aq Mt seanc@FreeBSD.org .
121.Sh BUGS
122No index is used when printing out tokens from the list which
123makes it rather slow for large files (10MB+).
124For smaller
125files, however, it should still be quite fast and efficient.
126