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Re: Error while writing to ...

2003-12-16 13:20:26
On Mon, 15 Dec 2003, Professional Software Engineering wrote:

PSE> Try adding 'i' to the recipe flags.  My gut feeling is that "mell"
PSE> terminates before reading the entire message from STDIN.

That will be it.  The program terminates when a match is found.

PSE> >This is the recipe where the program "mell" checks to see if it has seen a
PSE> >500 byte token before, and returns the number of occurances on stdout. The
PSE> >token is output on stderr. More than 3 occurances and it is bit bucket
PSE> >time.
PSE>
PSE> Sound interesting.  Where do the initial 500 byte tokens come from?
PSE>

The concept is that a token is 500 consecutive characters not containing
spaces, tabs, two consecutive end-of-lines and not allowing three
consecutive characters to be the same.  So in parsing the email, the first
valid token is stored, and if no further token matches one already in the
database, it is added to the database with a count of 1.

I started thinking about this a few months ago when the swen virus started
hitting my autoresponder.  If I allow one or two through, someone can send
me, say, a photograph but if I receive repeats, then something is wrong. I
seem to remember when I was playing with it before that it caught some
repeat spams as well.


-- 
Alan


( Please do not email me AS WELL as replying to the list.  Please
  address personal email to alan+1@ as lists@ is not read. A
  password autoresponder may be invoked if this email is very old. )


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