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/>.