Which file is typically utilized by the system administrator for startup commands?

The file that is typically utilized by the system administrator for startup commands is /etc/rc.local. This file is executed at the end of the multi-user runlevel, allowing administrators to run custom commands and scripts during system startup. This is especially useful for commands that need to run after the system has completed its boot sequence and initialized all standard services.

Using /etc/rc.local provides a straightforward way to add commands without modifying other system startup files directly, which could potentially disrupt essential system operations. The contents of this file are executed once, making it a convenient point for system customization for various administrative tasks.

While other options like /etc/inittab and /etc/init.d have roles in the startup sequence, they serve different purposes. The inittab file primarily configures the system's run levels and the processes that need to be started in each run level. The init.d directory contains scripts that start and stop services at different run levels, but it doesn't serve as a dedicated file for user-defined commands like /etc/rc.local does. Similarly, /etc/rc.d is a directory related to system boot activities but is not specifically focused on user-defined startup commands.