Urbit / Docs


Admin and operation

Your urbit (also called your ship) is a persistent Unix process that you mainly control from the console. For some things, a browser will also work.


You can turn your urbit off with Ctrl-d from the Talk or Dojo prompts.

You can force-quit your urbit with Ctrl-z from anywhere.


To restart your urbit simply pass the name of your pier:

$ urbit some-planet


$ urbit comet


To log an urbit's command line output to a file, use script:

$ script urbit.log urbit your-urbit

Moving your pier

Piers are designed to be portable, but it must be done while the urbit is turned off. Urbit networking is stateful, so you can't run two copies of the same urbit in two places.

To move a pier, simply move the contents of the directory it lives in. To keep these files as small as possible we usually use the --sparse option in tar. With a pier your-urbit/, something like this should work:

tar -Scvzf ~/your-urbit.tar.gz ~/your-urbit/
scp your-old-server:~/your-urbit.tar.gz your-new-server:~

Then to unzip it, on your other Unix server, run:

tar xfvz your-urbit.tar.gz

Delete the tar file, and, after installing Urbit on your new server, start your urbit back up with:

urbit your-urbit


Your Urbit terminal is separated into two parts: the prompt (the bottom line) and the record (everything above that). The record is shared; all the output from all the apps in your command set appears in it. The prompt is multiplexed.

In the CLI, Urbit apps can process your input before you hit return. To see this in action try entering ) as the first character at the Dojo prompt. Since there is no Dojo command or Hoon expression that starts with ')', the Dojo rejects it.

Ctrl-x - Switches the prompt between running console apps

Ctrl-c - Crash current event. Processed at the Unix layer and prints a stack trace.

Ctrl-d - From Talk or Dojo, stops your Urbit process.

Ctrl-z - Stops the Urbit process from anywhere.

/ - History navigation

The following emacs-style key bindings are available:

Ctrl-a    Cursor to beginning of the line (Home)
Ctrl-b    Cursor one character backward (left-arrow)
Ctrl-e    Cursor to the end of the line (End)
Ctrl-f    Cursor one character forward (right-arrow)
Ctrl-g    Beep; cancel reverse-search
Ctrl-k    Kill to end of line
Ctrl-l    Clear the screen
Ctrl-n    Next line in history (down-arrow)
Ctrl-p    Previous line in history (up-arrow)
Ctrl-r    Reverse-search
Ctrl-t    Transpose characters
Ctrl-u    Kill to beginning of line
Ctrl-y    Yank from kill buffer

Full coverage of the Urbit shell, the Dojo is covered in the Shell walkthrough.


On startup Urbit tries to bind to localhost:8080. If you're already running something on 8080 -- such as another urbit -- you'll find the urbit that you just started on 8081, and so on. For planets only, we also proxy web domains through Urbit's own servers. Any planet ~your-urbit is also at your-urbit.urbit.org.

Your urbit serves a simple homepage from http://localhost:8080 or https://your-urbit.urbit.org that should be self-explanatory. Since our HTTPS isn't audited / battle tested, we just call it “secure” HTTPS. You can find that on 8443. Or 8444 (and so on) if you're already running something on 8443.

A complete walkthrough of the Urbit web interface is here.


Urbit namespace is distributed by having parent nodes sign the keys for child nodes. If you have a planet, your parent star issued your ticket. As a planet you, in turn, can sign the keys for moons. The basic idea is: your planet runs permanently in a data center somewhere and moons run on all your devices. Each planet can issue ~4 billion (2^32) moons.

To generate a random moon from your planet, run:

~your-urbit:dojo> +moon

You can use the resulting output in the same installation flow from install and setup, following the same scheme as for booting a planet. That scheme is:

$ urbit -w <moonname> -t <ticket> -c <piername>

The -c <piername> argument is not required, but it is recommended; otherwise, the resulting directory is a rather unwieldy moon name.

Here's how an example moon might be booted:

$ urbit -w faswep-navred-sampel-palnet -t habref-mebsem-parsym-batlus -c mymoon

Moons are automatically synced to their parent %kids desk, and can control applications on their parent planet using |link. You can read more about those operations in the filesystem and console walkthroughs, respectively.

Continuity breaches

While the Urbit network is in this alpha state, we sometimes have to reboot the whole network. This happens either when major changes need to be shipped or we hit a bug that can't be fixed over the air.

Because Urbit networking is stateful we call this a continuity breach. Everything has to be restarted from scratch. Your pier will continue to function after we have breached, but it wont connect to the rest of the Urbit network.

When this happens, back up any files you'd like to save, shut down your urbit and recreate it (as if you were starting for the first time).

Creating SSL certificates

It is possible to create SSL certificates so that you serve files through your ship's webserver using https. To do that you, would need a machine that has OpenSSL installed. In order to create a new private key and a self-signed certificate for your localhost, valid for a year, you can issue the following commands:

$ openssl req -x509 -sha256 -newkey rsa:4096 -keyout private.pem -out certificate.pem -subj '/CN=localhost' -days 365
$ mkdir -p your-urbit/.urb/tls
$ mv private.pem certificate.pem your-urbit/.urb/tls

These certificates would have to be manually trusted by your browser, and it's advisable that they are used only for your localhost. For public-facing webservers, it would be better to create certificates for your fully qualified domain name using a trusted certificate authority like Let's Encrypt.