freebsd man page for rot13

CAESAR(6)							 BSD Games Manual							 CAESAR(6)

NAME
     caesar, rot13 -- decrypt caesar ciphers

SYNOPSIS
     caesar [rotation]
     rot13

DESCRIPTION
     The caesar utility attempts to decrypt caesar ciphers using English letter frequency statistics.  Caesar reads from the standard input and
     writes to the standard output.

     The optional numerical argument rotation may be used to specify a specific rotation value.  If invoked as rot13, a rotation value of 13 will
     be used.

     The frequency (from most common to least) of English letters is as follows:

	   ETAONRISHDLFCMUGPYWBVKXJQZ

     Their frequencies as a percentage are as follows:

	   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).

     Rotated postings to USENET and some of the databases used by the fortune(6) program are rotated by 13 characters.

BSD
								 November 16, 1993							       BSD