Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)

This error message indicates that there is a lock file in the /var/lib/dpkg/ directory, which prevents another process from accessing it. This issue commonly occurs when the package manager, such as apt or dpkg, is already being used by another program or process.

To resolve this issue, you can follow these steps:

1. Make sure you have administrative privileges by using the sudo command.
2. Check if any other package management processes are running by running the following command:

   ps aux | grep -i apt

This command will list any processes related to apt or dpkg.
3. If you find any processes running, you can either wait for them to finish or manually terminate them using their process IDs (PIDs).
4. If there are no running processes related to apt or dpkg, you can remove the lock file by running the following command:

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

5. Finally, try running your desired package management command again.

Please note that it's important to use caution when terminating processes, as it may lead to unexpected consequences.