Procmail hat sehr ausführliche man-pages (Handbuch-Seiten) â neben
man procmail lohnt sich auch man procmailex (Beispielrezepte),
man procmailsc und man procmailrc.
Ein Beispiel aus man procmailex:
If you are subscribed to several mailinglists and people cross-post to some of them, you usually receive several duplicate mails (one from every list). The following sim- ple recipe eliminates duplicate mails. It tells formail to keep an 8KB cache file in which it will store the Mes- sage-IDs of the most recent mails you received. Since Message-IDs are guaranteed to be unique for every new mail, they are ideally suited to weed out duplicate mails. Simply put the following recipe at the top of your rcfile, and no duplicate mail will get past it.
:0 Wh: msgid.lock | formail -D 8192 msgid.cache