问题:

I want to process a particular mailbox when it receives mail, I know I could have cron check every n minutes for any mail, but wondering if there's a way to "listen" for mail rather than continually polling.

回答1:

Try a .forward file

You can pipe the message into any program or script you want, but also check if procmail can do what you want.

回答2:

Depending on your mail server, it may be possible to actually have any incoming message be delivered to a process. Either in a .forward or by setting up something more advanced. In exim you can setup a transport to run a command, for certain addresses.

回答3:

If you're using postfix I'd suggest aliasing the mailbox you're interested in to a process that will do the work for you. Then there's no polling. The message comes in and goes directly to being processed.

回答4:

As Jason and Zoredache have already mentioned, you might be able to do this in the MTA itself. Another possibility is to have inotify watch the mailbox file or maildir.

回答5:

if you dont have a mail-server on your own (root-access) - you could use a web service for that: http://cloudmailin.net (200mails/month for free) - works like charme and helped me out.