Difference: Mail-relatedFiles (17 vs. 18)

Procmail

There are two places where you can put a procmail command file: /a/mail/procmailrc/$user or ~/.procmailrc. The latter name is the standard location for a procmail file, and it's supported at Nevis. The former location is preferred, however, since the file will remain available to the mail server if your home directory becomes unavailable; e.g., if your group's server goes down.

Many mail readers (such as Thunderbird) have similar facilities. The advantages of using procmail are:

• Procmail offers more flexibility than most mail readers. For example, most mail readers cannot send an e-mail in response to a particular message you receive; procmail can.

• Procmail runs on the mail server, which means it operates on your e-mail as it receives it. A mail reader can only process your messages as it reads them off the server. In particular, if you read mail using more than one computer or more than one mail-reading program, you might want to put your mail filtering in procmail instead of duplicating that functionality on different machines and programs.

The disadvantage is, of course, complexity; procmail uses its own command language.

If you're interested in exploring procmail, I recommend the following resources:

• Procmail FAQ and tips.
• The procmail man page.
• The procmailrc man page.
• The procmailex man page.
• WilliamSeligman's procmail file at /a/mail/procmailrc/seligman.

If you have both files /a/mail/procmailrc/$user and ~/.procmail, the commands in both will be executed. Be careful! This is not the behavior of the forwarding files described above!