# Pastebin tgLiJTku
# cat canonical.test; echo -- --; postmap /etc/postfix/canonical.test; postmap -q exception@example.com hash:/etc/postfix/canonical.test;postmap -q @example.com hash:/etc/postfix/canonical.test; echo -- ... --
@example.com somewhere@example.org
exception@example.com exception@example.com
-- --
exception@example.com
somewhere@example.org
-- ... --