Ask HN: I have ssh, they have ssh, how can we chat?

Maybe even spin up VMs on demand based on new hostname (if not seen before). First to claim = own. Some rate limiting function.

Shell accounts largely went away due to ease of use, but also local user exploits and abuse, but enh. If you virtualized the network (so you could reroute through a new IP on abuse, or let users own the IP) and restricted functionality it wouldn't be as bad.

No practical purpose, just fun.

Put this in your .bashrc file:

    function talk { echo "$USER: $@" >> talkfile; }

    tail -f talkfile &

You can both communicate simply by using the talk function like any other bash command:

    talk whatever you want and it'll be written to talkfile

It's nice because it records what you say, so there's no need for the other person to be logged in to get your message, and you get a printout of the last few lines of conversation when you "login" (run the tail -f command). There's nothing extra to install either.

(edit, apparently say is already installed on OS X, so I renamed the function "talk")

    #!/bin/bash
    # Simple chat system for when Skype is fucked.
    nick=${1?Usage: $0 nickname (e.g. $0 biturd)}
    chan=/tmp/yapchan
    echo "^D to exit chat." >&2
    tail -F "$chan" & tailpid=$!
    trap 'kill "$tailpid"' 0
    while IFS='' read -er line; do echo "<$nick> $line"; done >> "$chan"

There's also OpenSSL s_client/s_server for an encrypted connection, although you need to setup some certificates first.

https://en.wikipedia.org/wiki/Talk_(software)

screen -S chat

The other user types

screen -xr chat

    # you type:
    $ screen -S session1 vim file.txt
    # and they can type (as the same user)
    $ screen -x session1

    # or with tmux, you type:
    $ tmux new -s session1 vim file.txt
    # they type (as the same user)
    $ tmux a -t session1

But when you mention "wall(1)" it makes it sound like you want to connect to some internet accessible UNIX host via ssh and chat to others who are also connected to that host.

Option 2 would be less complex.

Depending on what software is installed on the host you connect to, there are many possibilities. Back in the old days, talk(1) could be used for split screen chats. Today, tmux(1) would be my choice. Anything that uses UNIX domain sockets could work.

Proof of concept:

Does Darwin have logger(1), syslogd(8) and /etc/syslog.conf(5)?

Decide where to log the messages, e.g., /var/log/messages

Edit /etc/syslog.conf

Start syslogd

logger "your message"

less /var/log/messages

less -F /var/log/messages

tail -f /var/log/messages

Messages have date, time, priority (if any) and hostname.

You said "something basic"; this is about as basic as it gets.