• Marc via dovecot:

How should I use 'doveadm search -u' to get the mailbox path where the message is stored?

https://doc.dovecot.org/main/core/man/doveadm-search.1.html states:

doveadm-search(1) - Show a list of mailbox GUIDs and message UIDs matching given search query.

I don't see how the search command could be used to return some kind of "path". Dovecot message stores are an abstraction layer. There are also mailbox formats like mdbox (multi-dbox) to consider, where a single file system object can contain multiple messages.

-Ralph