Answers for "Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 6740 (apt)"

Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?

ps aux | grep -i dpkg

// Kill processes which are running
sudo kill -9 <pid>

// Restart the accounts daemon
sudo systemctl restart accounts-daemon

E: Could not get lock /var/cache/apt/archives/lock - open (11: Resource temporarily unavailable) E: Unable to lock the download directory

sudo killall apt-get