procmailsc man page on BSDi

Man page or keyword search:  
man Server   6284 pages
apropos Keyword Search (all sections)
Output format
BSDi logo
[printable version]



PROCMAILSC(5)					    PROCMAILSC(5)

NAME
       procmailsc - procmail weighted scoring techique

SYNOPSIS
       [*] w^x condition

DESCRIPTION
       In  addition  to	 the traditional true or false conditions
       you can specify on a recipe, you can use a weighted  scor-
       ing  technique  to  decide  if a certain recipe matches or
       not.  When weighted scoring is used in a recipe, then  the
       final  score  for  that	recipe must be positive for it to
       match.

       A certain condition can contribute to  the  score  if  you
       allocate	 it a `weight' (w) and an `exponent' (x).  You do
       this by preceding the condition (on the same line) with:
	      w^x
       Whereas	both  w	 and   x   are	 real	numbers	  between
       -2147483647.0 and 2147483647.0 inclusive.

Weighted regular expression conditions
       The  first  time	 the regular expression is found, it will
       add w to the score.  The second time it is found, w*x will
       be  added.   The	 third	time  it  is found, w*x*x will be
       added.  The fourth time w*x*x*x will  be	 added.	  And  so
       forth.

       This can be described by the following concise formula:

				   n
		   n   k-1	  x - 1
	      w * Sum x	   = w * -------
		  k=1		  x - 1

       It  represents the total added score for this condition if
       n matches are found.

       Note that the following case distinctions can be made:

       x=0     Only the first match  will  contribute  w  to  the
	       score.  Any subsequent matches are ignored.

       x=1     Every  match  will  contribute  the  same w to the
	       score.  The score grows linearly with  the  number
	       of matches found.

BuGless			    2000/06/21				1

PROCMAILSC(5)					    PROCMAILSC(5)

       0<x<1   Every match will contribute less to the score than
	       the previous one.  The score  will  asymptotically
	       approach	 a  certain  value (see the NOTES section
	       below).

       1<x     Every match will contribute more to the score than
	       the  previous  one.   The score will grow exponen-
	       tionally.

       x<0     Can be utilised to favour odd or	 even  number  of
	       matches.

       If  the	regular expression is negated (i.e. matches if it
       isn't found), then n obviously can either be zero or  one.

Weighted program conditions
       If  the	program returns an exitcode of EXIT_SUCCESS (=0),
       then the total added score will be w.  If it  returns  any
       other exitcode (indicating failure), the total added score
       will be x.

       If the exitcode of the program is negated, then, the exit-
       code  will be considered as if it were a virtual number of
       matches.	 Calculation of the added score then proceeds  as
       if  it  had been a normal regular expression with n=`exit-
       code' matches.

Weighted length conditions
       If the length of the actual mail is M then:

	      * w^x  > L

       will generate an additional score of:

			 x
		  /  M	\
	      w * | --- |
		  \  L	/

       And:

	      * w^x  < L

       will generate an additional score of:

			 x
		  /  L	\
	      w * | --- |
		  \  M	/

       In both cases, if L=M, this will add w to the  score.   In
       the former case however, larger mails will be favoured, in
       the latter case, smaller mails will be favoured.	 Although

BuGless			    2000/06/21				2

PROCMAILSC(5)					    PROCMAILSC(5)

       x  can  be  varied to fine-tune the steepness of the func-
       tion, typical usage sets x=1.

MISCELLANEOUS
       You can query the final score of all the conditions  on	a
       recipe from the environment variable $=.	 This variable is
       set every time just after procmail has parsed  all  condi-
       tions  on  a  recipe (even if the recipe is not being exe-
       cuted).

EXAMPLES
       The following recipe will ditch all mails having more than
       150  lines  in  the body.  The first condition contains an
       empty regular expression which, because it always matches,
       is  used	 to give our score a negative offset.  The second
       condition then matches every line in the	 mail,	and  con-
       sumes  up  the previous negative offset we gave (one point
       per line).  In the end, the score will only be positive if
       the mail contained more than 150 lines.

	      :0 Bh
	      * -150^0
	      *	   1^1	^.*$
	      /dev/null

       Suppose	you  have a priority folder which you always read
       first.  The next recipe picks out the  priority	mail  and
       files them in this special folder.  The first condition is
       a regular one, i.e. it doesn't contribute  to  the  score,
       but  simply  has	 to  be	 satisfied.  The other conditions
       describe things like: john and claire usually  have  some-
       thing  important	 to  say, meetings are usually important,
       replies are favoured a bit, mails  about	 Elvis	(this  is
       merely  an  example  :-) are favoured (the more he is men-
       tioned, the more the mail is  favoured,	but  the  maximum
       extra score due to Elvis will be 4000, no matter how often
       he is mentioned), lots of quoted lines are disliked,  smi-
       leys  are  appreciated  (the  score for those will reach a
       maximum of 3500), those three people  usually  don't  send
       interesting  mails,  the	 mails should preferably be small
       (e.g. 2000 bytes long mails will score  -100,  4000  bytes
       long  mails do -800).  As you see, if some of the uninter-
       esting people send mail, then the mail still has a  chance
       of  landing  in the priority folder, e.g. if it is about a
       meeting, or if it contains at least two smileys.

BuGless			    2000/06/21				3

PROCMAILSC(5)					    PROCMAILSC(5)

	      :0 HB
	      *		!^Precedence:.*(junk|bulk)
	      * 2000^0	 ^From:.*(john@home|claire@work)
	      * 2000^0	 ^Subject:.*meeting
	      *	 300^0	 ^Subject:.*Re:
	      * 1000^.75 elvis|presley
	      * -100^1	 ^>
	      *	 350^.9	 :-\)
	      * -500^0	 ^From:.*(boss|jane|henry)@work
	      * -100^3	 > 2000
	      priority_folder

       If you are subscribed to a  mailinglist,	 and  just  would
       like to read the quality mails, then the following recipes
       could do the trick.  First we make sure that the	 mail  is
       coming  from the mailinglist.  Then we check if it is from
       certain persons of whom we value the opinion, or	 about	a
       subject	we  absolutely want to know everything about.  If
       it is, file it.	Otherwise, check if the ratio  of  quoted
       lines  to  original  lines  is at most 1:2.  If it exceeds
       that, ditch the mail.  Everything that survived the previ-
       ous test, is filed.

	      :0
	      ^From mailinglist-request@some.where
	      {
		:0:
		* ^(From:.*(paula|bill)|Subject:.*skiing)
		mailinglist

		:0 Bh
		*  20^1 ^>
		* -10^1 ^[^>]
		/dev/null

		:0:
		mailinglist
	      }

       For  further examples you should look in the procmailex(5)
       man page.

CAVEATS
       Because this speeds up the search by an	order  of  magni-
       tude,  the  procmail internal egrep will always search for
       the leftmost shortest match, unless it is determining what
       to assign to MATCH, in which case it searches the leftmost
       longest match.  E.g. for the leftmost shortest  match,  by
       itself, the regular expression:

BuGless			    2000/06/21				4

PROCMAILSC(5)					    PROCMAILSC(5)

       .*     will  always match a zero length string at the same
	      spot.

       .+     will always match one character (except newlines of
	      course).

SEE ALSO
       procmail(1), procmailrc(5), procmailex(5), sh(1), csh(1),
       egrep(1), grep(1),

BUGS
       If, in a length condition, you specify an x that causes an
       overflow,  procmail is at the mercy of the pow(3) function
       in your mathematical library.

       Floating point numbers in `engineering' format (e.g. 12e5)
       are not accepted.

MISCELLANEOUS
       As  soon	 as  `plus infinity' (2147483647) is reached, any
       subsequent weighted conditions will simply be skipped.

       As soon as `minus infinity' (-2147483647) is reached,  the
       condition  will be considered as `no match' and the recipe
       will terminate early.

NOTES
       If in a regular expression weighted formula 0<x<1, the to-
       tal added score for this condition will asymptotically ap-
       proach:

		 w
	      -------
	       1 - x

       In order to reach half the maximum value you need

		   - ln 2
	      n = --------
		     ln x

       matches.

AUTHORS
       Stephen R. van den Berg
	      <srb@cuci.nl>
       Philip A. Guenther
	      <guenther@sendmail.com>

BuGless			    2000/06/21				5

[top]

List of man pages available for BSDi

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net