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David Mandelberg

Automatic List Filtering with Procmail

by 1 Comment

I’ve been using procmail for a while, filtering mailing list messages into per-list folders with one rule per list. I recently decided to try automatically sorting lists by List-Id headers. When I searched for pre-built rules to do this, I found some that came close, but none that did what I wanted. So I wrote my own compound rule and posted it here. The below code sorts a List-Id like foo.example.com or foo.lists.example.com into the Maildir folder .Lists.example-com.foo.

:0
* ^List-Id: .*\/<[a-zA-Z0-9_-]+(\.lists)?\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+>$
{
    LISTID="$MATCH"
    :0
    * LISTID ?? ^<\/[a-zA-Z0-9_-]+
    {
        LISTID_PART1="$MATCH"
        :0
        * LISTID ?? ^<[a-zA-Z0-9_-]+(\.lists)?\.\/[a-zA-Z0-9_-]+
        {
            LISTID_PART2="$MATCH"
            :0
            * LISTID ?? ^<[a-zA-Z0-9_-]+(\.lists)?\.[a-zA-Z0-9_-]+\.\/[a-zA-Z0-9_-]+
            .Lists.${LISTID_PART2}-${MATCH}.${LISTID_PART1}/
        }
    }
}

This has a few advantages over other rules I found online:

  • The entire List-Id is used, not just the part before the first dot.
  • The resulting folders are hierarchical.
  • Only a limited character set is allowed in folder names. This prevents something like List-Id: <foo/../../../etc/passwd> from causing trouble.

It also has a few disadvantages:

  • It only works as intended for List-Ids of the form list-name.domain.tld or list-name.lists.domain.tld. Other List-Ids are either incorrectly assumed to be in one of those forms, or ignored.
  • It only supports a limited character set. This has security advantages, but usability disadvantages.
  • It does not place a limit on the length of the directory name. Unfortunately, procmail makes that difficult to do.
  • It converts dots in the domain into hyphens, but hyphens are allowed in domain names. This could cause both foo.bar-baz.quux and foo.bar.baz-quux to be sorted into the same folder, .Lists.bar-baz-quux.foo.
  • It’s a bit hard to read.

Department of Survival

by 2 Comments

I wish Brandeis had an academic department that offered classes relating to surviving in unusual circumstances. There would be a slight possibility of saving the lives of Brandeis students and alumns. The research done by faculty or students could likely help save the lives of other people. Even without saving any lives, it would be an interesting thing to put in promotional material that could differentiate Brandeis from other colleges and universities.

Here are some ideas that I had for classes the new Survival Department could offer:

  • Introduction to Survival
  • Finding, Extracting, Purifying, and Storing Water
  • Introduction to Foraging
    • Edible Fungi
  • Introduction to Hunting
  • Emergency Psychology (cross-listed in Psychology)
  • Introduction to Self-Defense
    • Defense Against Humans
    • Defense Against Predatory Animals
  • Making Tools
  • Finding and Making Shelter
  • Creating and Maintaining Fire
  • Making String, Rope, and Cloth
  • Emergency Signaling
  • Emergency Medicine
    • Medicinal Herbs
  • Readjusting to Civilization (cross-listed in Psychology and Sociology)

I think even one class along these lines would make Brandeis a much more interesting place and could make a Brandeis education much more valuable. Also, if anybody even thinks that a class helped them to save their life, they might be more likely to donate money to Brandeis.