Many cell phones now have the ability to receive email. While that can be very useful, large messages are often a problem both because they are hard to read and because one large message may be split up into multiple messages at the phone.
Sometimes, though, it’s important that certain messages get to you even though they may be large. That’s the situation one of my Mitel (E-Smith) mail server customers had: mail sent to a certain account was very important to know about, but he didn’t want the entire message shipped to his cell phone. As it turns out, this was an easy problem to solve.
Dash Addresses
One of the features of Qmail is support for “dash addresses”, in other words an ordinary account name followed by a “-” and some other word. I talked about this a bit in Mitel (E-Smith) SME Server Mail Forwarding and Listsbut these have a use here also.
The first thing to do is to arrange an account that we’ll use for this notification. I called it “notify”. Just add a user “notify” as you ordinarily would through the admin control panel. Next, we’re going to modify the user who gets the important mail. We can do that either by having that user also forward a copy to our “notify” user, or by turning that name into a group that includes the real user and our “notify” user. In either case, we then change “notify” so that its mail actually gets forwarded to “notify-sms”. You can do all this through the normal administrative web panels; no “Unix” required yet. Note also that we only created “notify”, not “notify-sms”.
Command Line Work
Now we do have to drop to the dreaded command line. In “notify”‘s home directory (cd ~notify) we need to create .qmail-sms for the address “notify-sms” to work. In there we need just one simple line:
-==-
That’s a pipe symbol followed by the address of a simple Perl program that handles the actual work:
-==-
Any mail sent to “notify-sms” goes to this program instead, and nowhere else. This simple script extracts the Subject, Date, and From lines and simply creates a new email message to one or more recipents. Technically “Subject” lines can span multiple lines; if you wanted to be sure to get all related lines this would need to be more complex, but for this usage the first would be all we’d want anyway.
That’s it. This concept can be expanded to handle all sorts of special mail handling tasks: junk mail filtering, special automatic replies, etc.
Copyright and Reprint Information
A.P. Lawrence provides SCO Unix and Linux consulting services http://www.pcunix.com
