could not get lock /var/lib/apt/lists/lock. It is held by process 7208 (packagekitd) code example
Example 1: E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?
sudo lsof /var/lib/dpkg/lock
sudo lsof /var/lib/apt/lists/lock
sudo lsof /var/cache/apt/archives/lock
Example 2: how to realse the lock in the linux in apt
sudo kill <process_id>