Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 1433 (unattended-upgr) code example
Example 1: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)
Method 1
ps aux | grep -i apt
sudo kill -9 <process_id>
Method 2
sudo lsof /var/lib/dpkg/lock
sudo lsof /var/lib/apt/lists/lock
sudo lsof /var/cache/apt/archives/lock
sudo kill -9 <process_id>
sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock
sudo dpkg --configure -a
sudo apt update
Example 2: E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
$ sudo dpkg --configure -a
dpkg: error: parsing file '/var/lib/dpkg/updates/0004' near line 0:
newline in field name '#padding'