Postfix – how do you redirect all emails to one user, eg *@example.com → user@example.com

Okay. And now a different approach.

Put a new transport in master.cf:

coolscript unix -    n    n    -    50    pipe
    flags=R user=vmail argv=/path/to/script -o SENDER=${sender} -m USER=${user} EXTENSION=${extension}

you can extend/modify the parameters as you like.

Then (to eliminate pcre) you can use regexp to do the "catch-thing" in main.cf:

transport_maps = regexp:/etc/postfix/redirect.regexp

And in /etc/postfix/redirect.regexp you put:

/^user-.*@example\.com/   coolscript:

Reload Postfix with postfix reload.

I'd be inclined to solve this using recipient_delimiter.

If you don't mind using slightly different Reply-To addresses, you can set:

recipient_delimiter = +

in your config, and then mail to e.g. notification+message-988742@mysite.com (note the +) will be delivered to the notification user (assuming there are no more-specific rules/users matching notification+message-988742).

You could try setting recipient_delimiter = - (so that you could use the Reply-To headers as they are in the question) but I'm not sure how that would work with multiple instances of the delimiter on the left-hand side, and I don't have a Postfix to hand to check.