What command can be used to configure a service to initiate at boot during specified run levels?

The command that is used to configure a service to initiate at boot during specified run levels is "chkconfig." This command is specific to certain Linux distributions, particularly those that use the SysV init system. It allows administrators to manage which services start at various run levels, providing the ability to enable or disable a service based on the desired run level configuration.

Run levels correspond to different states of the system that dictate which services and processes are active. For example, run level 3 typically represents a multi-user mode with networking, while run level 5 might include a graphical interface. By using "chkconfig," an administrator can set a service to start (or not) in these different run levels, shaping the system’s boot behavior according to operational needs.

The use of "systemctl enable," while relevant in the context of modern Linux systems using systemd, does not involve specifying run levels in the traditional sense utilized by SysV, making "chkconfig" the more appropriate choice in this context. Additionally, "service boot" and "init.d configure" do not represent valid commands for managing service startup configurations in the context described.