rot13 [options] <file1 ... fileN>
By default, only alphabetic characters are rotated. The -numrot option will also rotate numbers.
If no files are given on the command line, text on standard input will be translated. Output is usually written to standard output, but if the -replace option and a set of files are given, then the files will be translated in place.
This is a very well-known cipher and shouldn't be used for anything that must be kept secret. These days, it is often used for hiding spoilers in public postings. That's about the extent of what it should be trusted for.
A similar such program used to be standard, but it seems to have disappeared.
Copyright 2013 Wayne Morrison
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