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

       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

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
       2021-03-21.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-19.)  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 man-pages@man7.org

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)