Mounting /proc file system In order for certain programs to function properly, the proc file system must be available from within the chroot'ed environment. A file system can be mounted as many times and in as many places as you'd like, so it's not a problem that the proc file system is already mounted on your host system, especially so because proc is a virtual file system. The proc file system is mounted under /proc by running the following command. mount proc /proc -t proc