Reset root password by editing shadow file on Linux

• 1 Backup current file:
  cp /run/media/bob/disk/etc/shadow /run/media/bob/disk/etc/shadow.bak
  
• 2 Generate new password:
  perl -e 'print crypt("N3wPassw0rd","\$6\$salt\$") . "\n"'
  
• N $6$ means SHA-512
  

References

• https://unix.stackexchange.com/questions/158400/etc-shadow-how-to-generate-6-s-encrypted-password
• https://unix.stackexchange.com/questions/117592/why-user-and-root-passwords-cannot-be-empty-on-linux