dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it? code example

Example 1: 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

Example 2: dpkg: error: dpkg frontend lock is locked by another process

First, find out the id of the process that is holding the lock file:

lsof /var/lib/dpkg/lock-frontend

The above command will give you the PID of the processes using the lock files. Use this PID to kill the process:

sudo kill -9 PID

Now you can remove the lock and reconfigure dpkg:

sudo rm /var/lib/dpkg/lock-frontend
sudo dpkg --configure -a