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 cwd 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

       -V, --version
              Display version information and exit.

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

EXAMPLES

       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)

AVAILABILITY

       The   pivot_root   command   is   part   of   the   util-linux   package   and    is    available    from
       https://www.kernel.org/pub/linux/utils/util-linux/.