pivot_root(8) — Linux manual page


PIVOT_ROOT(8)               System Administration              PIVOT_ROOT(8)

NAME         top

       pivot_root - change the root filesystem

SYNOPSIS         top

       pivot_root new_root put_old

DESCRIPTION         top

       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         top

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

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

EXAMPLE         top

       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 and
       run init:

       ifconfig lo up   # for portmap
       # configure Ethernet or such
       portmap   # for lockd (implicitly started by mount)
       mount -o ro /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         top

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

AVAILABILITY         top

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

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-12.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

util-linux                       August 2011                   PIVOT_ROOT(8)

Pages that refer to this page: pivot_root(2)initrd(4)lxc.container.conf(5)mount_namespaces(7)pivot_root(8)