What command is used to immediately change to a provided target in systemd?

The command that is used to immediately change to a provided target in systemd is "systemctl isolate." This command allows the system administrator to switch the system to a specified target unit while stopping any units that are not dependencies of the target. Essentially, it transitions the system to the desired state defined by the target unit without needing to reboot the machine. This is particularly useful for changing run levels in a more flexible manner than traditional methods, enabling administrators to streamline operations based on the current needs of the system.

The other options do not serve this purpose. For instance, "systemctl set-target" is used to set a specific target as the default for the system but does not affect the current state immediately. "systemctl switch-target" is not an actual command in systemd, and "systemctl change-target" does not exist either. Thus, "systemctl isolate" is the appropriate choice for immediate target changes in systemd.