Updates and machines

How Tau updates#

You install Tau once. After that it keeps itself current, with or without a window open.

• Two minutes after it starts, and every six hours after that, Tau looks for a newer release.
• It downloads the release in the background and checks it against the release's SHA-512 checksum.
• It installs once no agent has run for a quarter of an hour, and never while one is working. With a window open, it waits until you choose Restart or quit.

Settings → About shows the version of the machine you're connected to, whether an update is waiting, Update now, and a switch for Automatic updates. Settings → General → Update track switches between stable releases and the nightly build.

Each kind of install updates in its own way:

• Mac: Tau replaces itself in Applications.
• Windows: the installer runs silently for your user.
• Debian and Ubuntu (.deb): a small helper installs the new package. Members of sudo, admin or wheel need no password, also on a server without a desktop.
• AppImage: replaces its own file.

From a terminal, tau update does the same (--check only looks, --status tells where it stands). The design and the threat model are in Host updates.

Another computer#

Pair a second Mac or a Linux box with the window you already use. Its threads show up in your list, and a new thread can start there.

With a link. On the other machine, open Settings → Connections, turn on network access and create a pairing link. On this one, open Settings → Machines and paste the link, type the other machine's address, or click Find machines to list the ones on your network. The other machine asks whether to let this computer in and shows six digits; allow it if this window shows the same six.

Over SSH. If you can already ssh to the machine, one command pairs the two:

tau machines add --ssh studio --agents

Tau must run on both machines. --agents also lets this computer's agents start work there.

Once paired:

• Run on under a new thread's heading picks the machine. Automatic picks the one with the most room when you send.
• A thread's title menu → Continue in… → On another machine hands a running thread over, with its history or a summary of it.
• Work from another machine comes back as a branch. Nothing is pushed to your Git remote on the way; the project travels over Tau's own encrypted connection.
• Settings → Machines shows every machine's cores, memory, running turns and runtimes, and updates them.

A host without a window#

On a server, or on a Mac you want to reach while no Tau window is open, Tau runs as a service: threads, terminals and paired devices keep going with no window open and after a restart.

tau service install     # install and start
tau service status      # where it stands, and its log
tau service uninstall   # stop and remove

Settings → Connections → Background does the same. On macOS it is a LaunchAgent, on Linux a systemd user unit, on Windows a Task Scheduler task. On Linux, tau service install --display adds an invisible display, so an agent's browser and GUI apps run where nobody sees them.

Hosts, machines and devices has the details: the service, a host over a socket or TLS, work on other machines, the web client and the phone app.

This page is docs/site/updates-and-machines.md in Tau's repository.