Re: Expanding email aliases

[Steffen Nurpmeso <steffen%sdaoden.eu@localhost>]

Martin Neitzel wrote in
 <20220726172558.1760B34893%marshlabs-mx.gaertner.de@localhost>:
 |SB> Is there a simple way of expanding an email alias, [...]
 |
 |The command
 |
 | sendmail -bv some_alias
 |
 |should help you.  With the original sendmail(8) you get the result
 |on stdout while with Postfix' sendmail-compatibility-shim ends you
 |an email with a pseudo delivery report, listing all alias expansions
 |as "Final-Recipients".

I was short of suggesting s-nail (the MUA i maintain), but for one
the package was not updated to the long current v14.9.24, then we
only support a subset of postfix aliases(5)

     mta-aliases
           [Option] If set to a path pointing to a text file in valid MTA
           (Postfix) aliases(5)[729] format, the file is loaded and cached
           (manageable with mtaaliases[236]), and henceforth plain ‘name’ (see
           expandaddr[417]) message receiver names are recursively expanded as
           a last expansion step, after the distribution lists which can be
           created with alias[144].  Constraints on aliases(5)[730] content
           support: only local addresses (names) which are valid usernames
           (‘[a-z_][a-z0-9_-]*[$]?’) are treated as expandable aliases, and
           [v15 behaviour may differ] ‘:include:/file/name’ directives are not
           supported.  By including ‘-name’ in expandaddr[417] it can be
           asserted that only expanded names (mail addresses) are passed
           through to the MTA.

and then this mail made me realize that we support the desired
functionality for Mail aliases, but not for MTA aliases; the
mtaaliases command only offers show aka list mode

  $ s-nail -RS mta-aliases=/tmp/test -X 'mtaa;x'
  root: steffen
  mltest: "|\"/usr/local/lib/s-ml/urunml send.sh testml /tmp\""
  mailer-daemon: postmaster
  postmaster: root
  bin: root
  daemon: root
  ...

and the output is wrapped to fit on the terminal.  But what he
wants is this:

  $ s-nail -# -X 'alias ich;x'
  alias ich 'Steffen Nurpmeso <steffen%sdaoden.eu@localhost>'

I was in implementing it in the other window.
(It is not _so_ trivial to implement postfix aliases(5).)

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)