ETRN(8)

📦 version 8.18.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💌 etrn(8) — the System Administration Commands girlies know

okay bestie so listen, this is etrn(8), and she's a tiny little tool with main character energy. her whole job? start mail queue run. that's it. that's the vibe. 👑

✨ NAME ✨

etrn — start mail queue run 💖

🌸 SYNOPSIS 🌸

etrn [-v] server-host [client-hosts]

like look at her. one option. she's not doing too much. she's serving simplicity. 💅

🦋 DESCRIPTION 🦋

okay so SMTP has this command called ETRN, right? and what it does is let an SMTP client and an SMTP server interact — specifically, it hands the server an opportunity to start processing its queues for messages that need to go out to a given host. it's giving "hey girl, go check your mailbox and actually send the stuff." 💌

this is meant to be used in start-up conditions, and also for mail nodes that have transient connections to their service providers. iykyk — those nodes that pop in and out, not always online. ✨

so here's how etrn does her thing. she initiates an SMTP session with the host server-host, and then she sends one or more ETRN commands. the details:

  • if no client-hosts are specified, etrn looks up every host name for which sendmail(1M) accepts email, and for each name, sends an ETRN command with that name as the argument. every single one. she's thorough. 💅
  • if any client-hosts are specified, etrn uses each of these as arguments for successive ETRN commands. one after another. slay.

🎀 OPTIONS 🎀

the following option is supported (yes, just one, and she's iconic for it):

  • -v — the normal mode of operation for etrn is to do all of its work silently. the -v option makes it verbose, which causes etrn to display its conversations with the remote SMTP server. so if you wanna eavesdrop on the whole exchange, this is your girl. 👀💬

🌈 ENVIRONMENT 🌈

No environment variables are used.

literally none. she doesn't need them. unbothered. unproblematic. 💜

📁 FILES 📁

  • /etc/mail/sendmail.cf — sendmail configuration file

👑 SEE ALSO 👑

go read those too, bestie. expand your mind. 🧚

💀 CAVEATS 💀

Not all SMTP servers support ETRN.

fr fr. so don't come crying to me when some random server is like "ETRN? never heard of her." 😭

⭐ CREDITS ⭐

Leveraged from David Muir Sharnoff's expn.pl script. Christian von Roques added support for args and fixed a couple of bugs. we love a collaborative effort. 🫶

🍓 AVAILABILITY 🍓

The latest version of etrn is available in the contrib directory of the sendmail distribution through anonymous ftp at:

ftp://ftp.sendmail.org/ucb/src/sendmail/

💜 AUTHOR 💜

John T. Beck <john@beck.org>

and that's the whole page, bestie!! 🎀 this was etrn(8) from the System Administration Commands family — shoutout to John T. Beck <john@beck.org> for writing her, love that for us, mwah 💋✨

📦 where this page comes from