Pointer: Foiling spam and other procmail email-filter tips

Timo Salmi

The gentle readers processing their email on a Unix-system, or
getting their email through a Unix-based system, might be interested
in the following information.

Timo's procmail tips and recipes

Last-Modified: Sun 24-Jun-2007 20:20:38

1. I want to filter my email automatically. How do I get started
with procmail?

2. Building a testbench. How can I test individual procmail
recipes?

3. I know how to make "and" rules in procmail recipes, but how do I
make "or" rules?

4. How can one perform multiple shell commands on the action line?

5. How can I find out what the subject of a posting is?

6. How do I get a copy of the headers of all the incoming email
into a separate file?

7. Would you give some further hints for spam foiling recipes?

8. I have limited disk space. How can I truncate long messages?

9. How can I quickly test if my rules with regular expressions
match?

10. How can I detect if the email comes, say, from the .com domain?

11. What alternatives do I have to detect a sender all through the
various header-fields?

12. How can I extract a valid address from the Reply-To field?

13. How can I extract the address of the sender's postmaster?

14. How can I weed out an inordinately long recipient list?

15. What is this procmail scoring? How can I utilize it?

16. How can I test if the subject is empty or if the subject field
is missing altogether?

17. How can I modify the "To:" field of the email I received?

18. I have a long list of spammers in a separate file. How can I
utilize it?

19. How do I forward certain messages that I get, and preserve
myself a copy?

20. How do I forward certain messages to two different addresses?

21. How do I automatically return certain email messages?

22. My address has changed. How do I forward a copy to myself and
tell the sender?

23. How can I set variable values based on the text in the body of
the email message?

24. How can I insert some token text in front of the body of
incoming email?

25. Do you have any useful tips for regular expression matching?

26. How can I test if two procmail variables have the same contents?

27. I am having difficulties with "<". How does one match it?

28. How can I insert identification text to the beginning of the
subject line?

29. I tried out your tips, but some of them failed on my system.
What next?

30. Is there a cure for the echo and grep blues?

31. How do I know which of my many procmail recipes has been
enacted?

32. How can I detect Korean, Cyrillic, or Chinese to avoid such
frequent spam?

33. How can I change the subject line and include part of the message
body to it?

34. How can I remove the signature from the incoming email?

35. What unix manuals relating to procmail should I get?

36. Is it possible to use procmail to call the vacation program?

37. How can I avoid duplicate messages sent in rapid succession?

38. How can I skip logging a certain, matched recipe?

39. Could you please solve for me this procmail problem of mine?

40. I liked this material. Do you have anything else on programming?

41. Exercises

42. Acknowledgements for useful advice and/or feedback

All the best, Timo

--
Prof. Timo Salmi ftp & archives 193.166.120.5
Department of Accounting and Business Finance ; University of Vaasa
mailto: <http://www.uwasa.fi/~ts/> ; FIN-65101, Finland
Digital photos collection at