Various file systems exported by the kernel are used to communicate to and from the kernel itself. These file systems are virtual in that no disk space is used for them. The content of the file systems resides in memory.

Begin by creating directories onto which the file systems will be mounted:

mkdir -pv $LFS/{proc,sys}

Now mount the file systems:

mount -vt proc proc $LFS/proc
mount -vt sysfs sysfs $LFS/sys

Remember that if for any reason you stop working on the LFS system and start again later, it is important to check that these file systems are mounted again before entering the chroot environment.

Additional file systems will soon be mounted from within the chroot environment. To keep the host up to date, perform a “fake mount” for each of these now:

mount -vft tmpfs tmpfs $LFS/dev
mount -vft tmpfs tmpfs $LFS/dev/shm
mount -vft devpts -o gid=4,mode=620 devpts $LFS/dev/pts