E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?

Solution:
→ sudo rm /var/lib/dpkg/lock
→ reboot

apt upgrade ERROR!
dpkg /var/lib/dpkg/status no such file or directory

Solution:
→ sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status
or
→ sudo touch /var/lib/dpkg/status