You get the following error message while installing a .deb package on Debian or Ubuntu or while installing Updates?
E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?
This error means that there is already an apt process running or the apt process dies and left his lock file.
First, you should wait a few minutes to ensure that the lock has not been set by the automatic update job (in case you enabled automatic updates on your system). If you just run an apt command and this command ended abruptly e.g. due to a disconnect of your SSH session, then there is no need to wait.
When the same error still shows up after you waited some time, then it's time to fix the issue by removing the stale apt lock file.
Run this command to remove the lock file:
sudo rm -f /var/lib/dpkg/lock
Now you should be able to run the original apt command successfully.