chroot Command
Advanced System Information man(1)Run command or shell with a different root directory
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📅 Updated: Apr 28, 2026
SYNTAX
chroot NEWROOT [COMMAND]
What Does chroot Do?
chroot changes the root directory for a command or shell session. The process and its children see the specified directory as / and cannot access files outside of it (without special effort).
chroot is used for system recovery (booting into a broken system), building packages in isolated environments, testing software in a minimal filesystem, and basic containerization.
chroot provides filesystem isolation but is not a security boundary — processes with root access can escape a chroot. For proper isolation, use containers (Docker, LXC) or namespaces.
chroot is used for system recovery (booting into a broken system), building packages in isolated environments, testing software in a minimal filesystem, and basic containerization.
chroot provides filesystem isolation but is not a security boundary — processes with root access can escape a chroot. For proper isolation, use containers (Docker, LXC) or namespaces.
Options & Flags
| Option | Description | Example |
|---|---|---|
| NEWROOT | New root directory | sudo chroot /mnt/recovery |
| COMMAND | Command to run (default: /bin/sh) | sudo chroot /mnt/sysimage /bin/bash |
| --userspec | Run as specific user:group | sudo chroot --userspec=www-data:www-data /app |
| --groups | Set supplementary groups | sudo chroot --groups=audio,video /jail |
Practical Examples
#1 System recovery
Mounts a broken system and chroots into it for repair.
$ sudo mount /dev/sda1 /mnt && sudo chroot /mnt /bin/bash#2 Fix bootloader
Repairs GRUB from a live USB by chrooting into the installed system.
$ sudo chroot /mnt /bin/bash -c 'grub-install /dev/sda && update-grub'#3 Run in isolated env
Opens a shell in a minimal filesystem for package building.
$ sudo chroot /srv/build /bin/bash#4 Recovery with proc/sys
Full recovery chroot with required virtual filesystems.
$ sudo mount --bind /dev /mnt/dev && sudo mount -t proc proc /mnt/proc && sudo mount -t sysfs sys /mnt/sys && sudo chroot /mnt#5 Run specific command
Runs nginx in a chrooted environment.
$ sudo chroot /jail /usr/bin/nginxTips & Best Practices
Not a security boundary: chroot is NOT a security container. Root processes can escape chroot. Use proper containers (Docker, LXC) for security isolation.
Mount virtual filesystems: For full system recovery: mount /dev, /proc, /sys, and /dev/pts before chrooting. Otherwise many tools will not work.
debootstrap for minimal environments: Use debootstrap to create a minimal Debian/Ubuntu filesystem for chroot: debootstrap focal /path/to/chroot
Frequently Asked Questions
How do I repair a broken Linux system?
Boot from live USB, mount the partition, mount /dev /proc /sys, then chroot into it. Now you can fix grub, packages, configs.
Is chroot secure?
No — chroot provides filesystem isolation but root processes can escape. Use Docker, LXC, or bubblewrap for security.
What do I need inside a chroot?
At minimum: /bin/sh, shared libraries, and basic utilities. Mount /dev, /proc, /sys for system tools to work.
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