What command is used to build the kernel module dependency file?

The command used to build the kernel module dependency file is depmod. This command scans all the currently installed modules and generates a list of dependencies for each module, which is then stored in a file, typically located in the /lib/modules/$(uname -r)/modules.dep. This dependency file is crucial for the proper loading of kernel modules, as it helps the kernel understand which modules are dependent on others.

Using depmod ensures that when you run a command like modprobe to load a module, the system knows about the dependencies of that module and can load any required modules automatically. This enhances the modularity of the Linux kernel, allowing for flexibility in managing drivers and kernel features without requiring recompilation.

Other options listed do not serve this purpose: modprobe is used for loading modules into the Linux kernel but does not handle dependency file creation directly, while modprobe install and modprobe remove are not valid commands in the context of dependency file management. Thus, depmod is the correct choice for building the kernel module dependency file.