Three days ago, I tried installing the second of two Ubuntu Linux 16.04 versions side by side on the same Lenovo Thinkstation desktop using the procedure described in this URL, https://askubuntu.com/questions/13977/dual-booting-two-ubuntu-versions.
When the installation finished, I got the console message, "The installation completed successfully. Please restart the system."
When I restarted the Lenovo Thinkstation computer desktop, it asked me create new user which I did. But I lost the former user, linux3 , from the first Ubuntu Linux 16.04 instance by inadvertently deleting libc.so.6 in the old first instance.
I lost the user, linux3 , from my Ubuntu Linux 16.04 instances because I can no longer login after rebooting my Ubuntu Linux 16.04 instance, even after I selected the partition(s) corresponding to the old Ubuntu instance in grub2 because I mistakenly "sudo" deleted the soft link, libc.so.6 , and libc-2.23.so in the subfolder /lib/x86_64-linux-gnu.
Here is the error message when rebooting the Ubuntu Linux 16.04 instance halts prematurely.
/sbin/init: error while loading shared libraries: libc.so.6 cannot open shared object file: No such file or directory [14.578123] Kernel panic: --not syncing : Attempted to kill init! exitcode=0x00007f00`
I was hoping for a critique of these two possible ways to regain access to the user , linux3 , and all the files and directories associated with it such as /lib by using an USB drive which contains libc.so.6 and libc-2.23.so and copying the the soft link, libc.so.6 , and libc-2.23.so over to the subfolder /lib/x86_64-linux-gnu from grub2 recovery mode.
Otherwise, how might I do this using my side by side Ubuntu Linux 16.04 instance in another partition with username , siblings?
Any help is greatly appreciated.