made mail archive script fully idempotent, added another link to resources doc

src/mailsrv/assets/bin/maint

@@ -7,11 +7,8 @@ for user in *; do
     # we don't mind if it already exists)
     doveadm mailbox create -u $user -s Archive 2> /dev/null
 
-    # get current year
-    currentyear=$(date +%Y)
     # assume no messages in INBOX are older than this year
-    #year=2000
-    year=$(($currentyear-1))
+    year=2000
     while [[ $year -le $currentyear ]]; do
         # create an Archive/$year mailbox
         doveadm mailbox create -u $user -s Archive.$year 2> /dev/null
@@ -30,10 +27,14 @@ for user in *; do
         doveadm move -u $user Archive.$year SEEN BEFORE 1-Jan-$(($year+1)) \
                                             BEFORE 90d \( $mailboxes \)
 
-        # delete messages from Trash that have been there for more than 2 weeks
-        doveadm expunge -u $user SAVEDBEFORE 2w MAILBOX Trash
+	# delete Archive/$year mailbox if it is empty
+	doveadm mailbox delete -u $user -e Archive.$year 2> /dev/null
 
         # step year variable
         year=$(($year+1))
     done
+
+    # delete messages from Trash that have been there for more than 2 weeks
+    doveadm expunge -u $user SAVEDBEFORE 2w MAILBOX Trash
+
 done

src/mailsrv/docs/Resources.md

@@ -7,3 +7,7 @@
   - says to use `@` for subdomain, but Dyn only accepts `*` as wildcard
 - https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-dkim-with-postfix-on-debian-wheezy
 - https://www.linuxbabe.com/mail-server/create-dmarc-record
+
+## Best Practices
+
+- https://bridge.grumpy-troll.org/2020/07/small-mailserver-bcp/