problem with getmail and cron


I’ve configurated one mail server with postfix+getmail+dovecot. It goes well, but I’ve a problem with the automatic retrive of the email by getmail and cron or crontab. Infact if I run getmail from the shel with “getmail -r <file>” It works correctly and, because I set “read_all = false”, it retrive only the new mail. The problem is that I want to do this automatically when the system boot. I try to do this makeing a text file in cron.d like “*/1 * * * * user getmail -r file”. Getmail starts correctly and It retrive the new mail but it doesn’t remenber what are the new mail (it doesn’t set them as “seen”) so every minute it retrive the mail as well untill i run getmail from the shel. I try even with crontab but it doesn’t works. How can I retrive automatically ONLY the new mail ONLY ONE TIME? Thank You for everything.