1PIVOT_ROOT(8)                System Administration               PIVOT_ROOT(8)
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NAME

6       pivot_root - change the root filesystem
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SYNOPSIS

9       pivot_root new_root put_old
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DESCRIPTION

12       pivot_root moves the root file system of the current process to the
13       directory put_old and makes new_root the new root file system. Since
14       pivot_root(8) simply calls pivot_root(2), we refer to the man page of
15       the latter for further details.
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17       Note that, depending on the implementation of pivot_root, root and
18       current working directory of the caller may or may not change. The
19       following is a sequence for invoking pivot_root that works in either
20       case, assuming that pivot_root and chroot are in the current PATH:
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22           cd new_root
23           pivot_root . put_old
24           exec chroot . command
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26       Note that chroot must be available under the old root and under the new
27       root, because pivot_root may or may not have implicitly changed the
28       root directory of the shell.
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30       Note that exec chroot changes the running executable, which is
31       necessary if the old root directory should be unmounted afterwards.
32       Also note that standard input, output, and error may still point to a
33       device on the old root file system, keeping it busy. They can easily be
34       changed when invoking chroot (see below; note the absence of leading
35       slashes to make it work whether pivot_root has changed the shell’s root
36       or not).
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OPTIONS

39       -V, --version
40           Display version information and exit.
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42       -h, --help
43           Display help text and exit.
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EXAMPLE

46       Change the root file system to /dev/hda1 from an interactive shell:
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48           mount /dev/hda1 /new-root
49           cd /new-root
50           pivot_root . old-root
51           exec chroot . sh <dev/console >dev/console 2>&1
52           umount /old-root
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54       Mount the new root file system over NFS from 10.0.0.1:/my_root and run
55       init:
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57           ifconfig lo 127.0.0.1 up   # for portmap
58           # configure Ethernet or such
59           portmap   # for lockd (implicitly started by mount)
60           mount -o ro 10.0.0.1:/my_root /mnt
61           killall portmap   # portmap keeps old root busy
62           cd /mnt
63           pivot_root . old_root
64           exec chroot . sh -c 'umount /old_root; exec /sbin/init' \
65             <dev/console >dev/console 2>&1
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SEE ALSO

68       chroot(1), pivot_root(2), mount(8), switch_root(8), umount(8)
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REPORTING BUGS

71       For bug reports, use the issue tracker at
72       https://github.com/karelzak/util-linux/issues.
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AVAILABILITY

75       The pivot_root command is part of the util-linux package which can be
76       downloaded from Linux Kernel Archive
77       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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81util-linux 2.37.2                 2021-06-02                     PIVOT_ROOT(8)
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