You can use the dpkg command to see what packages are installed on Ubuntu Linux. The following command will list all installed packages:
dpkg --list
This will display a list of all packages installed on the system, including their names, versions, and descriptions.
Another way to see installed packages is to use the apt command:
apt list --installed
This will show a list of all packages installed on the system and their versions. You can use the grep command to filter the output for specific packages:
apt list --installed | grep <package-name>
Replace <package-name> with the name of the package you want to search for.