May 26, 2018
[ excerpt from developer’s site ]
SpamOracle, a.k.a. “Saint Peter”, is a tool to help detect and filter away “spam” unsolicited commercial e-mail. It proceeds by statistical analysis of the words that appear in the e-mail, comparing the frequencies of words with those found in a user-provided corpus of known spam and known legitimate e-mail. The classification algorithm is based on Bayes’ formula, and is described in Paul Graham’s paper, A plan for spam.
This program is designed to work in conjunction with procmail. The result of the analysis is output as an additional message header X-Spam, followed by yes, no or unknown, plus additional details. A procmail rule can then test this X-Spam header and deliver the e-mail to the appropriate mailbox.