Root and Particle Users on Tachyon
Tachyon devices are configured out of the box with two Linux user accounts:
root– the system administrator account with unrestricted privileges.particle– the default, non-privileged user account for day-to-day use.
Understanding the difference between these two users is essential for developing safely and avoiding system damage or accidental configuration loss.
1. The Root Account
The root user is the superuser on the system - it has magical powers.
It can modify any file, install or remove any package, and start or stop any process. When you run commands as root, the system does not ask for confirmation - it simply obeys.
You can think of root as driving without a seatbelt on a racetrack. You have complete control, but also complete responsibility. A single mistyped command can delete critical files or render the system unbootable.
For that reason, most daily workflows and examples avoid logging in directly as root. It’s best reserved for system maintenance, driver installation, and low-level debugging.
2. The Particle Account
The particle user is the default login and is created so that your interactive sessions aren’t performed as root.
This user has limited privileges - enough to run applications, manage files, and develop software, but not enough to modify protected system areas without explicit permission.
This separation provides a safety net - much like driving a car with traction control. It keeps you productive without risking system stability.
In addition, the underlying Ubuntu-based system requires a normal user account for many services to start correctly; operating as root full-time can actually break expected permissions and service behavior.
3. Which Terminal Uses Which Account
Different console or terminal access methods on Tachyon log you into different accounts by default:
| Access Method | Default User | Notes |
|---|---|---|
| Serial / Debug Port | root | Used for development, factory, and maintenance. Auto-login enabled for dev builds. |
| Desktop Terminal (on device) | particle | The normal terminal window inside the graphical desktop environment. |
| Particle Console (Remote Console) | root | Intended for field maintenance or recovery. Provides full system access. |
| SSH Access | Depends on login | Use ssh root@<device> for root access or ssh particle@<device> for standard access. |
4. Running Commands That Require Elevated Permissions
When you are logged in as the particle user and need to run a command that requires administrative privileges, you have several options.
Option 1 – Run a Single Command with sudo
Use sudo followed by the command you want to execute. You’ll be prompted for your password (if configured):
sudo apt update
sudo systemctl restart networking #example command that needs root to operate
This executes only that specific command with elevated privileges and then returns you to the particle context.
Option 2 – Enter a Root Shell with sudo -s
If you need to perform multiple root-level operations:
sudo -s
This launches a root shell while preserving your environment. You’ll notice the prompt changes to show root@tachyon:~#, indicating that you now have superuser privileges.
To exit the root shell and return to the particle user, type:
exit
Option 3 – Switch Users with su
If you prefer to switch users manually:
su root
This command will switch your session to the root user (password required if set). Once again, your prompt will update to reflect the active user:
particle@tachyon:~$ # logged in as particle
root@tachyon:~# # now operating as root
5. Understanding the Prompt
Your Linux prompt always shows which user is active - look for the username before the “@” symbol:
particle@tachyon:~$ ← safe, normal user
root@tachyon:~# ← full system access
Keeping an eye on this indicator helps you know when you’re operating in a privileged context.