Exim4 Sieve filter.

The filter contains an automatic response and a forwarding.

router

userforward:
  driver = redirect
  allow_filter
  user = mail
  group = mail
  file = /var/vmail/${domain}/${local_part}/${if exists{/var/vmail/${domain}/${local_part}/active_script}{active_script{}}}{forward}}
  no_verify
  no_expn
  check_ancestor
  file_transport = local_delivery
  pipe_transport = address_pipe
  reply_transport = address_reply
  condition = ${if exists{/var/vmail/${domain}/${local_part}/forward}{yes}{${if exists{/var/vmail/${domain}/${local_part}/active_script}{yes}{no}}}}

Transport

local_delivery:
  driver = appendfile
  check_string = ""
  delivery_date_add
  directory = /var/vmail/${domain}/${local_part}/${sg{${sg{/${address_file}}{/+}{.}}}{(?i)^.inbox}{}}
  directory_mode = 770
  envelope_to_add
  group = mail
  maildir_format
  maildir_tag = ,S=$message_size
  message_prefix = ""
  message_suffix = ""
  mode = 0660

active_script

# Sieve filter
require ["fileinto", "copy", "vacation"] ;

#begin = forward =
#data=1~dGlub0BuYXVtaXguZGU=                                                                                                                                                                                                                  
redirect :copy "copy@domain.tld";

#end = forward =

#begin = autoresponder =
#data=1~YXV0b3Jlc3BvbmQAZGFzIGlzdCBlaW5lIGF1dG9tYXRpc2NoZSBtYWls
vacation :days 1 :subject "Automatic Mail" "This is automatic Mail";
#end = autoresponder =

https://debian-administration.org/users/lee/weblog/43