The GEHACK workstation ships as a single bootable image, gehack-teammachine.iso. It is the same NixOS 26.05 system as a real team machine — same GNOME desktop, compilers, editors and tooling — packaged as a live USB so you can boot it on almost any PC without installing anything.

Download the ISO

Looking for what’s on the machine? See the Contest Environment.

Writing the ISO to a USB stick

The image is hybrid (BIOS and UEFI bootable) and is written as a whole disk (not a partition).

⚠️ Writing to the wrong disk erases it. Double-check the device name before running any command — there is no undo. All data on the target USB stick is destroyed.

GUI (any OS, easiest)

balenaEtcher works on Linux, macOS and Windows: select gehack-teammachine.iso, select the USB stick, click Flash. On Windows, Rufus is a good alternative (use DD Image mode when prompted).

Linux

lsblk                            # identify the USB, e.g. /dev/sdb (NOT /dev/sdb1)
sudo dd if=gehack-teammachine.iso of=/dev/sdb bs=4M status=progress oflag=sync
sync

macOS

diskutil list                    # identify the USB, e.g. /dev/disk4
diskutil unmountDisk /dev/disk4
sudo dd if=gehack-teammachine.iso of=/dev/rdisk4 bs=4m   # note: rdisk4 is faster than disk4
diskutil eject /dev/disk4

Booting and logging in

Boot the target machine from the USB stick (usually F12 / F11 / Esc at power-on to open the boot menu, or enable USB boot in the BIOS/UEFI settings). The image boots on both BIOS and UEFI systems.

There is no login screen: GDM auto-logs the team user straight into GNOME. You land on the desktop ready to work.

Two accounts exist, both with the password password:

User Role Password
team contest user (auto-logged in) password
gehack administrator (sudo/wheel) password

sudo runs without a password prompt — but only as the gehack user, which is the only administrator. The auto-logged-in team user is a plain contest account: it cannot sudo, and su to another user is blocked as well. Log in as gehack for anything that needs root.

The judge website

On the live image Firefox opens the public DOMjudge demo at www.domjudge.org/demoweb as its homepage (real team machines point at the contest judge instead, which is only reachable on the contest network). Log in to that demo instance with:

Field Value
Username team
Password team

The submit command is pointed at the same demo instance, so you can try the full submit-and-judge flow end to end.

Good to know