freebsd-skq/usr.bin/caesar/caesar.6
Colin Percival 6ae1554a5d Final step of eliminating the "games" distribution: Merge src/games
(or what's left of it, at least) into src/usr.bin.

This change will not be MFCed.

Discussed at:   EuroBSDCon 2014
Committed from: EuroBSDCon 2015
2015-10-02 10:08:11 +00:00

74 lines
2.7 KiB
Groff

.\" Copyright (c) 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
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.\" @(#)caesar.6 8.2 (Berkeley) 11/16/93
.\" $FreeBSD$
.\"
.Dd November 16, 1993
.Dt CAESAR 6
.Os
.Sh NAME
.Nm caesar , rot13
.Nd decrypt caesar ciphers
.Sh SYNOPSIS
.Nm
.Op Ar rotation
.Nm rot13
.Sh DESCRIPTION
The
.Nm
utility attempts to decrypt caesar ciphers using English letter frequency
statistics.
.Nm Caesar
reads from the standard input and writes to the standard output.
.Pp
The optional numerical argument
.Ar rotation
may be used to specify a specific rotation value.
If invoked as
.Nm rot13 ,
a rotation value of 13 will be used.
.Pp
The frequency (from most common to least) of English letters is as follows:
.Bd -ragged -offset indent
ETAONRISHDLFCMUGPYWBVKXJQZ
.Ed
.Pp
Their frequencies as a percentage are as follows:
.Bd -ragged -offset indent
E(13), T(10.5), A(8.1), O(7.9), N(7.1), R(6.8), I(6.3), S(6.1), H(5.2),
D(3.8), L(3.4), F(2.9), C(2.7), M(2.5), U(2.4), G(2),
P(1.9), Y(1.9),
W(1.5), B(1.4), V(.9), K(.4), X(.15), J(.13), Q(.11), Z(.07).
.Ed
.Pp
Rotated postings to
.Tn USENET
and some of the databases used by the
.Xr fortune 6
program are rotated by 13 characters.