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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLE | SEE ALSO | AVAILABILITY | COLOPHON |
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PIVOT_ROOT(8) System Administration PIVOT_ROOT(8)
pivot_root - change the root filesystem
pivot_root new_root put_old
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).
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
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
chroot(1), pivot_root(2), mount(8), switch_root(8), umount(8)
The pivot_root command is part of the util-linux package and is
available from
https://www.kernel.org/pub/linux/utils/util-linux/.
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
2020-12-18. (At that time, the date of the most recent commit
that was found in the repository was 2020-12-17.) 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)
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