I had upgraded ubuntu12.04 to ubuntu14.04 and it didn't boot unless I edited this line in the grub menu
linux ${rel-dirname}/${basename} root=${lINUX_HOST_DEVICE} loop=${loop_file_relative} ro ${args}
from ro
to rw
but I didn't save this change and boot by press F10. Then I update the file /etc/sudoers
with wrong syntax and I can't use sudo
command and I forgot the password for the root.
How I can gain root privilege ??