chroot

Change the root directory for a command

TLDR

Run a command with a different root directory

$ sudo chroot [path/to/new_root] [command]

Run an interactive shell in the new root

$ sudo chroot [path/to/new_root]

Specify a custom shell to run

$ sudo chroot [path/to/new_root] /bin/bash

Specify user and group for the command

$ sudo chroot --userspec=[user:group] [path/to/new_root] [command]

Change to a specific directory after chrooting

$ sudo chroot [path/to/new_root] /bin/sh -c "cd /home && ls"

SYNOPSIS

chroot [OPTION] NEWROOT [COMMAND [ARG]...]

chroot changes the root directory of the calling process to the specified path and runs a command within that environment. All pathname lookups starting with / will be relative to the new root.
If no command is specified, chroot runs the shell from the SHELL environment variable or defaults to /bin/sh.
The new root directory must contain all necessary files, libraries, and device nodes required by the command being executed.

PARAMETERS

NEWROOT

The directory to use as the new root filesystem

COMMAND

Command to run in the chroot environment

ARG

Arguments to pass to the command

--userspec=USER:GROUP

Specify user and group (name or ID) to run as

--groups=GROUPS

Specify supplementary groups

--skip-chdir

Do not change working directory to /

CAVEATS

Requires root privileges or CAP_SYS_CHROOT capability. Not designed for security sandboxing—privileged users can escape by creating directories and using relative paths. Open file descriptors may provide access outside the chroot.
The new root must contain essential files: /bin/sh or the specified command, required shared libraries (check with ldd), and device nodes like /dev/null if needed.

HISTORY

The chroot system call originated in Version 7 Unix (1979) at Bell Labs. It was initially used for building and testing new system versions. The GNU coreutils version provides the standard command-line interface on Linux systems.