How to recover the Linux VM after accidentally deleting all root folders?

Question

I have a CentOS Linux VM running in VirtualBox. I wrote a bash script to do some automated tasks. But I accidentally deleted all root folders because I put a line in the script

rm -r $my_dir/*

However, $my_dir is not found so the above will execute as rm -r /*. So now all my root folder contents are gone! When I restart my VM, it goes to grub terminal and can't launch the GNOME and bash shell because everything under / was accidentally deleted due to the above fault (lesson learned). So is there anyway to safely recover and restore the system either from in the VirtualBox or outside?

Answer 1

You could try to recover the files using a bootable CD from https://www.runtime.org/data-recovery-live-cd.htm

Boot the CD within Virtualbox and follow the instructions on the website.

Extra:

In all languages it is recommended to always perform input validation. This is not different when using bash scripting. I have seen servers been compromised because of the lack of input validation.

man test

This will explain how to perform some validation to determine if a string is null or empty:

   -n STRING
          the length of STRING is nonzero

   STRING equivalent to -n STRING

   -z STRING
          the length of STRING is zero

So what you should do is:

if [ ! -z $my_dir ]; then

   rm -r $my_dir/* 

fi

NOTE: If the variable is not properly sanitized like in the example above, and the input is coming from an argument, it is possible to break out and run other commands:

Example:

$ ./mybashscript.sh [directory]

By giving the following argument for [directory]: test; rm -rf /

The script will delete a folder called "test" (if it exists) and then the root directory (/).