A guide to SDF, part II: everything else you can do there

In part I we went through SDF's history, created an account, logged in, found our way around the bulletin board and the chat, and put a first web page online. If you followed along, you now have a home in one of the oldest public Unix systems still running.

part I

Now let's move in properly. This part covers everything else you can do there, and how: email from the terminal, gopher holes and phlogs, USENET, games, moving files, vintage computers, the fediverse, and what changes when you become an ARPA or MetaARPA member. As always, I'm there as pmurad.

SDF's 1990s setup of AT&T 3B2 minicomputers and terminals, shown at the Vintage Computer Festival in 2003

That's the machinery SDF ran on until about 1997, shown at the Vintage Computer Festival in 2003, where it won first place in the minicomputer class.

Email, the old way

Every SDF account comes with an email address: `yourlogin@sdf.org`, which also works as `yourlogin@freeshell.org`. Send yourself a message from your usual inbox and let's read it from the shell.

mutt works from day one, even before validation. Type:

mutt

You'll see your inbox. The keys you need:

When you write, mutt opens your text editor. Write, save, quit the editor, and you land on a compose screen where `y` sends it.

alpine (and the older pine) arrive after validation, and they're the friendliest option if you want menus and help on screen. Just type `alpine`.

Webmail is available to validated users through the webmail link on the SDF homepage. MetaARPA members also get a nicer Roundcube interface.

Reading on your phone or computer. Validated users can use IMAP with the server `mx.sdf.org`, or POP3 with `pop3.sdf.org` on port 110, using your login and password. Sending is the tricky part: SDF's outgoing mail server is reserved for members with VPM, VHOST or MetaARPA dues. Free and ARPA members can compose locally and send through their own provider, or deliver through an SSH session to SDF running `sendmail -t`, which has a much better chance of reaching the inbox.

Gopher, the other internet

Gopher is a protocol from 1991 that lost the war to the web, and it's having a quiet second life. It's only menus and text, with no images or scripts and nothing tracking you. SDF is one of the few places that still actively hosts it, and every member gets 20 MB of gopherspace.

Start with:

mkgopher

It gives you a small prompt of its own. Type `setup` first, and it creates a `gopher` folder in your home directory. Then, from the same prompt:

Your gopherspace will live at `gopher://sdf.org:70/1/users/yourlogin/`. To browse gopher from the shell, use the `gopher` command, or Lynx, which speaks gopher too:

lynx gopher://sdf.org/

From a normal web browser, you can visit any gopher hole through Floodgap's proxy at gopher.floodgap.com/gopher/gw.

gopher.floodgap.com/gopher/gw

If you'd rather manage files by hand, remember that the server only shows what everyone can read. These two commands fix the permissions for the whole folder:

find ~/gopher/ -type f -print0 | xargs -0 chmod 644

find ~/gopher/ -type d -print0 | xargs -0 chmod 755

To shape a menu yourself, put a file called `gophermap` in a folder. Each line starts with a one-character type (`0` for text, `1` for a folder, `h` for a web link, `i` for plain information), followed by the text, a tab and the path.

A phlog, a blog on gopher

A phlog (or glog) is a gopher log, a blog that lives on gopher. SDF has a script that does the boring part for you. Write your post in a plain text file and run:

mkgopherentry "My first post" post.txt

If the command isn't found, it lives at `/sys/sdf/bin/mkgopherentry`. It adds the entry to your phlog menu with the date, the first paragraph and a "Continued..." link to the full text. Then run `phlog` to add yourself to the gopher.club phlog listing, so other people can find you. After each new post, this command bumps you to the top of the list:

touch ~ftp/pub/users/$LOGNAME

There's a lovely community of phloggers out there, and reading them through Lynx at night feels like discovering a secret library.

A few more ways to say hello

Besides bboard and com from part I, SDF has a handful of small social tools:

And there are galleries you can contribute to from the shell: `deskshots` for a picture of your desktop, `artgallery` for art and photography, `vintage` for old computers, `sdfers` for a picture of yourself.

USENET

Before forums and social networks, there was USENET: thousands of newsgroups, replicated across servers around the world. SDF still gives you read and post access, right from the shell.

Create a file called `.newsrc` in your home directory with the groups you want, one per line, each ending with a colon:

comp.os.cpm:

comp.lang.lisp:

rec.music.makers.synth:

Then open a newsreader. `tin` and `trn` are the popular ones. You can post from inside the reader, or with the `postnews` command. If you use alpine, set the news server to `news.sdf.org`.

Games

SDF has a huge collection of text games. Type `games` to see the list. Some favorites from the collection:

Most games use the vi keys to move: h, j, k and l. If you loved or hated something, `game-review` lets you write a review for ascii-games.org.

SDF even has a Minecraft server at `mc.sdf.org`. It's whitelist only, so ask on the MINECRAFT board in bboard to be added.

Moving files and using keys

Once validated, you can send files to SDF from your computer with `scp` or `sftp`:

scp photo.jpg yourlogin@sdf.org:~/html/

sftp yourlogin@sdf.org

Plain FTP is only for public downloads, because it sends passwords in the clear.

To stop typing your password every time, use an SSH key. On your own computer:

ssh-keygen -t ed25519

ssh-copy-id yourlogin@tty.sdf.org

If your computer doesn't have `ssh-copy-id`, paste the contents of your `.pub` file into `~/.ssh/authorized_keys` on SDF.

One small trap: if your shell's startup files print a lot of text, scp and sftp can fail. Keep `.profile` quiet, or only print things in interactive sessions.

Vintage systems

Besides the NetBSD machines, SDF keeps a collection of historic systems online that you can actually log in to: TOPS-20 (the operating system of the DEC PDP-10 mainframes), ITS, and Symbolics Genera, the operating system of the old Lisp machines.

A Symbolics 3640 Lisp machine from SDF's collection in 1994

That's a Symbolics 3640 Lisp machine, photographed at SDF in 1994. To see the menu of vintage systems, connect with:

ssh menu@tty.sdf.org

Playing Zork on a TOPS-20 system the way people did in the late seventies is a strange and wonderful experience.

SDF on the fediverse and beyond

SDF isn't stuck in the past. It runs modern community services too:

mastodon.sdf.org

pixelfed.sdf.org

lemmy.sdf.org

matrix.sdf.org

anonradio.net

When you become ARPA

The ARPA membership costs $36, once, for the lifetime of SDF. Type `arpa` in the shell to read about it. Here's what opens up:

The back of SDF's server rack in 2021, full of red and white network cables

When you become MetaARPA

MetaARPA is a sustaining membership for ARPA members, at $11 a quarter. It's for people who want to really live on SDF. Type `meta` to read about it.

Extras for bigger projects

If you want to go further, SDF offers add-ons, all listed on the join page:

join page

Some advice for the long run

Log in now and then. Free validated accounts expire after two years without a shell login, and reading mail by IMAP or webmail doesn't count.

Use the help that's there. `faq`, `help`, `man` and the tutorials answer almost everything. The SDF wiki has more.

tutorials

SDF wiki

Be part of it. Reply on HELPDESK when you know the answer, and say hello in com now and then. SDF has lasted since 1987 because people kept showing up and caring about it.

And if SDF helps you, give something back. ARPA is cheap, and donations keep the machines running for the next person who types `ssh new@sdf.org` for the first time.

I'm pmurad there. Find me in com, or visit sdf.org/~pmurad. See you in the fortress.

sdf.org/~pmurad

sdf.org · Part I · Join · Tutorials

**sdf.org**

Part I

Join

Tutorials

Sources

SDF join page

membership FAQ

email at SDF

mutt

gopher

file transfer

SSH keys

ASCII gaming

SDF specific commands

git

USENET FAQ

account expiration

SDF vintage systems via SSH

Minecraft

SDF tour

Gemlog

Home

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