это совместимая оболочка, которая вызывает dracut для генерации initramfs  (is a compat wrapper, which calls dracut to generate an initramfs)
  
Имя (Name)
mkinitrd - is a compat wrapper, which calls dracut to generate an
       initramfs
Синопсис (Synopsis)
mkinitrd [OPTION...] [<initrd-image>] <kernel-version>
Описание (Description)
mkinitrd creates an initramfs image <initrd-image> for the kernel
       with version <kernel-version> by calling "dracut".
           Important
           If a more fine grained control over the resulting image is
           needed, "dracut" should be called directly.
Параметры (Options)
--version
           print info about the version
       -v, --verbose
           increase verbosity level
       -f, --force
           overwrite existing initramfs file.
       *--image-version
           append the kernel version to the target image
           <initrd-image>-<kernel-version>.
       --with=<module>
           add the kernel module <module> to the initramfs.
       --preload=<module>
           preload the kernel module <module> in the initramfs before
           any other kernel modules are loaded. This can be used to
           ensure a certain device naming, which should in theory be
           avoided and the use of symbolic links in /dev is encouraged.
       --nocompress
           do not compress the resulting image.
       --help
           print a help message and exit.
Доступность (Availability)
The mkinitrd command is part of the dracut package and is
       available from https://dracut.wiki.kernel.org