Learnt from this article by Dave McKay .
Create the root directory of the chroot environment if it doesn’t exist.
1chr=/home/ricky/testroot
2mkdir -p $chr
Create necessary directories and then get into the environment.
1mkdir -p $chr/{bin,lib,lib64}
2cd $chr
Copy the binaries we need for surviving on this “barren land”.
1cp -v /bin/{bash,touch,ls,rm} $chr/bin
For each of these binaries file, discover its library dependencies and then copy them as well into the environment. The following code does this only for bash. Adapt and run it for touch, ls and rm as well.
1# Example with /bin/bash.
2# Do this for /bin/{touch,ls,rm} as well
3list="$(ldd /bin/bash | egrep -o '/lib/.*\.[0-9]')"
4for i in $list; do cp -v --parents "$i" "$chr"; done
Finally, chroot into the environment and specify which program to run right after the environment changing. Note that we should specify a program within the environment, as we had already lost access to the outer space at this moment (and that’s why we put a bash binary inside).
1sudo chroot $chr /bin/bash
Now the prompt is most probably changed, and you should be able to use ls, touch, rm and those bash built-in commands.
