PIVOT_ROOT(8)                System Administration               PIVOT_ROOT(8)

NAME
       pivot_root - change the root filesystem

SYNOPSIS
       pivot_root new_root put_old

DESCRIPTION
       pivot_root moves the root file system of the current process to the
       directory put_old and makes new_root the new root file system. Since
       pivot_root(8) simply calls pivot_root(2), we refer to the man page of
       the latter for further details.

       Note that, depending on the implementation of pivot_root, root and
       current working directory of the caller may or may not change. The
       following is a sequence for invoking pivot_root that works in either
       case, assuming that pivot_root and chroot are in the current PATH:

           cd new_root
           pivot_root . put_old
           exec chroot . command

       Note that chroot must be available under the old root and under the new
       root, because pivot_root may or may not have implicitly changed the
       root directory of the shell.

       Note that exec chroot changes the running executable, which is
       necessary if the old root directory should be unmounted afterwards.
       Also note that standard input, output, and error may still point to a
       device on the old root file system, keeping it busy. They can easily be
       changed when invoking chroot (see below; note the absence of leading
       slashes to make it work whether pivot_root has changed the shell's root
       or not).

OPTIONS
       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

EXAMPLE
       Change the root file system to /dev/hda1 from an interactive shell:

           mount /dev/hda1 /new-root
           cd /new-root
           pivot_root . old-root
           exec chroot . sh <dev/console >dev/console 2>&1
           umount /old-root

       Mount the new root file system over NFS from 10.0.0.1:/my_root and run
       init:

           ifconfig lo 127.0.0.1 up   # for portmap
           # configure Ethernet or such
           portmap   # for lockd (implicitly started by mount)
           mount -o ro 10.0.0.1:/my_root /mnt
           killall portmap   # portmap keeps old root busy
           cd /mnt
           pivot_root . old_root
           exec chroot . sh -c 'umount /old_root; exec /sbin/init' \
             <dev/console >dev/console 2>&1

SEE ALSO
       chroot(1), pivot_root(2), mount(8), switch_root(8), umount(8)

REPORTING BUGS
       For bug reports, use the issue tracker at
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       The pivot_root command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.40                   2024-04-01                     PIVOT_ROOT(8)