220-1102 Question 4
Single answerLinuxA technician is troubleshooting a Linux workstation that no longer reaches the graphical login screen after a video driver update. The system stops at a text console, but the technician can log in locally with an administrative account. The technician wants to disable the GUI temporarily so the PC will continue booting to a command-line environment for further troubleshooting and package rollback. Which command should the technician use?
- A
systemctl set-default multi-user.target
- B
systemctl isolate graphical.target
- C
init 6
- D
chmod +x /etc/X11/xorg.conf
Show answer and explanation
Correct answer: A
Explanation
The best answer is "systemctl set-default multi-user.target" because A+ candidates are expected to recognize practical Linux administration tasks such as changing boot targets for troubleshooting. On systemd-based distributions, multi-user.target is analogous to a text-mode, network-enabled multiuser state, while graphical.target includes the graphical display manager and desktop environment. Using systemctl set-default changes the persistent default for subsequent boots, which is exactly what the scenario requires. By contrast, systemctl isolate changes the active target for the current session only, and selecting graphical.target would attempt to start the GUI rather than disable it. This aligns with standard systemd administration practices documented in systemctl and systemd target documentation used by major distributions such as Red Hat, Ubuntu, and SUSE.
- A. Correct.
Correct. On Linux systems that use systemd, setting the default target to multi-user.target configures the system to boot into a non-graphical, multi-user command-line environment. This is a practical troubleshooting step when the GUI is failing, because it allows the technician to boot reliably, log in at the console, and repair or roll back graphics-related packages without the display manager starting automatically.
- B. Incorrect.
Incorrect. systemctl isolate graphical.target attempts to switch the currently running system into the graphical target, which is the opposite of what the technician wants. If the graphical environment is already broken, isolating graphical.target could fail or worsen the issue by trying to start the display manager and GUI services.
- C. Incorrect.
Incorrect. init 6 reboots the system. Although older SysV-style runlevels are still mapped on some distributions, this command does not set the system to boot into a text-only mode on future startups. It simply restarts the machine, so it does not solve the requirement to disable the GUI temporarily.
- D. Incorrect.
Incorrect. chmod +x /etc/X11/xorg.conf makes little sense in this scenario because xorg.conf is a configuration file, not a script or executable that should be given execute permissions. Changing its mode this way would not disable the graphical environment or change the system's default boot target.