getcost, version 3.0
			    Sun May  4, 1997

==============================================================================
Forward by RAM:

	This version of getcost CANNOT be redistributed separately from the
mailagent it came with. As part of the mailagent distribution, it may be
copied freely.

	Darryl Okahata kindly granted me the permission to redistribute it as
well as a stripped-out sample of the spamconfig file. This is what lies
within this directory, along with the README file.
==============================================================================

     Getcost is a (somewhat kludgy) Perl script designed to detect SPAM.
It reads in a single, incoming mail message from standard input, and
prints a "cost", or message score, to stdout.  Its purpose is to assign
a "cost" to the mail message; if the cost is less than zero, it's
considered to be SPAM.  If the cost is greater than or equal to be zero,
it's not considered to be SPAM.

     Getcost is designed to be used in conjunction with mail filtering
programs like deliver(8) or procmail(1).  Basically, if getcost returns
a negative number, the message is considered to be SPAM, and deliver(8)
or procmail(1) should file the message into a "junkmail" folder.  It is
recommended that the message *NOT* be deleted, as getcost can
incorrectly classify a valid message as SPAM (this is known as a "false
positive").

     The cost is computed from various "scores", which are stored in a
configuration file in the user's $HOME directory.  The configuration
file contains a list of pattern/score pairs.  Basically, if an header
field or line in the message body matches a pattern, the corresponding
score is added to the "cost".  After processing all of the header and
body lines (body scanning can stop prematurely, to help with long
messages), the total cost is printed to stdout.

     Patterns can be matched against the following headers:

	From: & Reply-To:
	Sender:
	To: & Cc:
	Received
	Subject:

In addition, special kludgy code exists to handle the headers:

	X-Openmail-Hops:
	Newsgroups: & Xref:
	References: & In-Reply-To:\s/i & X-Also-Posted-To:

     Also, if 10 or more all-uppercase lines exist in the body, a score
of -10000 is added to the cost.  Each all-uppercase line must be more
than 10 characters long, *AND* no patterns must have matched for this
line, in order for it to be counted.  [ Yes, this is a bit kludgy, but,
believe it or not, the code has greatly improved since it was first
conceived. ]

     Questionable code also exists to automatically mark the message as
SPAM if the To: header is more than 1000 characters long.  This code
should probably be deleted/modified.

     Scanning stops as soon as the cost goes above 1000000 or below
-100000.

     This distribution includes three files:

	getcost		-- The SPAM-detecting engine.
	getcost.README	-- This file.
	spamconfig	-- A sample configuration file, with comments.
			   To use this file, either copy it to
			   $HOME/.spamconfig, or use getcost with the
			   "-f" option (see below).

     For debugging a configuration file, "-d" and "-D" options are
provided (see below).

     Note that $HOME should be set when this script is executed, so that
getcost can locate its config file.  If $HOME is not set, the "-f"
option (see below) must be used.


***** Options:

	-a	Apply all body rules, i.e. do not stop scoring for a body line
	    at the first match.  Scoring always stops when the delta cost
		associated with a pattern match is 0.

	-B	Penalize binary characters.  Each line that contains a
		character with bit 7 set gets a score of -100.  This is
		done only if no other patterns matched.

	-b	Don't do any score processing on the message body.
		Scoring is done only upon the message header.

	-c	Collect sentences and only apply patterns on full ones. This
		is useful in conjunction with -a, and also fights spam messages
		with a word on each line, to specifically defeat scoring filters
		which rely on consecutive words. This has no impact on -L, which
		still focuses on physical lines in the message, not logical ones.

	-D	(For debugging)  Dump scanner code.  For performance
		reasons, the scanner for the message body is converted
		into Perl code at runtime.  This option dumps out the
		converted Perl code, in case syntax errors occur (which
		can be common, as the regular expressions are taken
		directly from the configuration file).

	-d	(For debugging)  Debug mode.  Prints out how each line
		is assigned a score.  This option is invaluable for
		seeing how getcost arrives at a cost.

	-f  configfile
		Use "configfile" instead of $HOME/.spamconfig

	-k  Keep going applying the rules, even when the -1000000
		threshold is reached. Useful in conjunction with -d on a
		tty to debug a set of patterns.

	-L	Penalize long lines.  Lines greater than 90 characters get
		assigned a cost of: -(10 + line_length).  For example, a
		110-character long line is assigned a cost of -(10 + 110)
		or -120.  This is done only if no other patterns
		matched.

	-m	Multiple matches: apply pattern everywhere on the line, not
		just once. Useful with -c, to keep counting everything.
		NB: this re-uses the deprecated "-m" flag which was adding
		500 to the cost when your name appeared in the To: line.

	-o	If the X-Openmail-Hops: header line exists, assign a
		cost of 10000000 to the line.  Generally used to allow
		all openmail messages through.

	-S	If the To: header contains the phrase "list suppressed",
		a cost of -1000000 is assigned.  This is of questionable
		use (but, messages from spammers who use Eudora often
		have this).