[Spambayes] updating x-spambayes-classification on already trained mail?

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    Alex> For my test, I reran sb_filter.py on each message (maildir
    Alex> format, but not sure it matters) and discovered the following:

    Alex>   a) sb_filter.py doesn't seem to change the header if it already
    Alex>   exists in the message

Hmmm...  works for me.  spam.multi is an mbox message dating from Oct
2006 that already has classification and evidence headers:

    % egrep -i x-spam spam.multi
    X-Spambayes-Evidence: '*H*': 0.16; '*S*': 0.74; 'content-type:image/jpeg': 0.16;
    X-Spambayes-Classification: spam; 0.79
    % sb_filter.py < spam.multi | egrep -i x-spam
    X-Spambayes-Classification: spam; 0.99
    X-Spambayes-Evidence: '*H*': 0.00; '*S*': 0.98; 'received:70.86': 0.16;

    Alex>   b) using sed to remove X-Spambayes-Classification from the
    Alex>   messages, and rerunning sb_filter.py doesn't seem to reinsert
    Alex>   the header with a new score

If you need to fiddle with message headers you'll be much happier using
formail instead of sed.

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