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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | 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
2018-02-02. (At that time, the date of the most recent commit that
was found in the repository was 2018-02-01.) 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), pivot_root(8)
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HTML rendering created 2018-02-02 by Michael Kerrisk, author of The Linux Programming Interface, maintainer of the Linux man-pages project. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.
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