Mendel Development Tool (mdt) is a command-line tool that lets you communicate with a
device running Mendel Linux. The
mdt command facilitates a variety of device actions such as
opening a shell, installing Debian packages, pushing and pulling files, and more.
The server-side component that runs on the Mendel device is included with the Mendel system image.
So you only need to install the
mdt client on your host computer.
You can install it with
pip as follows:
pip3 install --user mendel-development-tool
--userflag installs the
mdtexecutable in your user directory. On Linux, that's
~/.local/bin/. On a Mac, it's something like
/Users/yourname/Library/Python/3.7/bin/. If you remove that flag, it requires root access and will install at
/usr/local/bin. So make sure that the appropriate path is in your
If you prefer
apt-get then you can also use that:
# Add the repo: echo "deb https://packages.cloud.google.com/apt coral-mdt-stable main" | sudo tee /etc/apt/sources.list.d/mdt.list # Add Google keys curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - # Then install the package: sudo apt-get update sudo apt-get install mendel-development-tool
Connect to a board's shell
MDT can access the shell on any Mendel device that's visible on your network, but the easiest option is to connect with a USB-C cable as shown in figure 1.
Then if you have just one device, run this command:
If multiple devices are available, you need to specify the name or IP address (you can list
all devices with
Internally, this is a normal SSH connection using OpenSSH with key-based
authentication. So before you can connect to the device shell with MDT or any other SSH tools, you
must push a public key to the device's
/home/mendel/.ssh/authorized_keys file. If no such key
exists there, the
mdt shell command creates it and pushes it (you can also do this manually with
mdt genkey and then
mdt pushkey). This key created by MDT is PEM-formatted, passwordless,
and saved on your host computer at
~/.config/mdt/keys/mdt.key (this key is used only when
If you prefer to use other SSH tools, simply generate your own key and then push that one
to the device with
mdt pushkey. For example, run the following on your host computer:
ssh-keygen # Follow steps to create key mdt pushkey ~/.ssh/id_rsa.pub ssh firstname.lastname@example.org
The following table provides a reference of the available commands you can use with
mdt subcommand arguments
man mdtfor information about what commands are available in your version of MDT.
||Returns a list of device names and IP addresses found on the local network
segment. Also indicates if a given device is marked as your default.
Note: MDT uses a python implementation of mDNS ZeroConf for discovery, so it does not require a running Avahi daemon.
||Waits for a device to be discovered on the network.|
||Returns the value currently set for a given variable name. Some useful
If no variable name is provided, 'mdt get' will print out the list of all known stored variables and their values. Note: default values are not printed.
||Sets the value for a given variable name. See example variables for the corresponding
Note that setting a variable to the empty string does not clear it back to
the default value. Use
||Clears the value for a given variable name, resetting it back to its default value.|
||Generates an SSH key and stores it to disk on the Mendel device.
If you already have an MDT key, this replaces it, effectively locking you out from any
boards that require authentication using that existing key. You must also remove
the keys previously stored on the Mendel device in
||Copies an SSH public key to the Mendel device's
||Copies a PEM-format SSH private key into the Mendel device's MDT keystore for use with authentication later.|
||Resets a device to it's pre-MDT state by removing all MDT keys and restarting the mdt-keymaster on the device so that new keys can be pushed again.|
||Opens an interactive shell to either your preferred device or to the first
If device-or-ip-address is specified, shell attempts to connect to that
device name or directly to the IP address provided instead.
Uses the variables
If no SSH key is available on disk (you didn't run
||Opens a non-interactive shell to either your preferred device or to the first
device found, runs a shell command and returns the output and the exit code.
If no SSH key is available on disk, it follows the same steps as the
||Installs a given Debian package file to the connected device via
Note: if the package provided has dependencies that are not already installed on the device, this will require internet connectivity to fetch and install those dependencies.
Pushes (copies) a local file or set of files to the remote device.
Uses the variables
||Pulls (copies) a set of files from the remote device to a local path.
Uses the variables
||Reboots a device.|
||Reboots a device into the bootloader.|
||Prints which version of MDT this is.|
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