rails provides [rake tasks][rake] to forward mails to [action mailbox][actionmailbox]'s [relay ingress][postfix].
that's fine unless you have your mail server(s) on another system and don't want to install rails (and all dependencies, i.e. the ruby runtime).
since the rake tasks basically just [upload stdin to your rails app via http][relayer] you can do everything with curl.
action-mailbox-relayer.sh
#!/usr/bin/env sh
curl -sS -u "actionmailbox:$INGRESS_PASSWORD" \
