.TH ROT13 1 "01 Sept 1994" "Linux" "Linux Programmer's Manual"
.SH NAME
rot13 \- shroud text with simple rot-13 cypher
.SH SYNOPSIS
.B rot13 
[input [output]]
.SH DESCRIPTION
This manual page
documents 
the
.BR rot13
text filter.
If no filenames are specified, 
.B rot13 
reads from stdin and writes to
stdout.  If one filename is specified, 
.B rot13 
reads from that file and writes to stdout.  If two filenames are specified, 
.B rot13 
reads from the first file and writes to the second file. You may use
.B rot13
inside the vi editor just as you would other filters, e.g. fmt.
.PP
.B Rot13
performs Usenet-standard rot-13
encryption.  This is done by taking the input letter and shifting it
left by 13 characters, so an A becomes an N, a B becomes an O, and so
forth. Applying
.B rot13
a second time restores the original text. The encrypted version of the
sentence `The quick brown fox jumps over the lazy dog.' looks like this:
.nf

\	Gur dhvpx oebja sbk whzcf bire gur ynml qbt.

.fi
.PP
Note that rot-13 is obviously not secure encryption. The main purpose of 
.B rot13
is to shield sensitive eyes from potentially offensive or disturbing
public messages. Most news readers provide a command to decode 
.B rot13 
messages.  For example, the tin news reader uses the command 'd'.
.SH AUTHOR 
The original author is Marc Unangst.  Various ways of contacting him are:
.nf
\	mju@mudos.ann-arbor.mi.us
\	...!umich!leebai!mudos!mju
\	Marc Unangst of 1:2200/129.0@fidonet.org
.fi
.PP
The 1994 update was done by Thomas McWilliams. See Changelog in the
source distribution for details.
.SH COPYING
Distribution permitted under the terms of the GNU General Public
License, version 2 (or later versions at your preference). Copies
of this agreement are available from:
.nf

\	Free Software Foundation, Inc., 
\	675 Mass Ave, 
\	Cambridge, MA 02139, USA.

.fi
