How to List Installed Packages in Ubuntu using Dpkg

In Ubuntu, we use apt-get to install and remove packages. To list all the packages installed on the system, one needs to run
$ dpkg --get-selections

To search for a certain package name, say python, among the list, one needs to pipe the result to grep,
$ dpkg -get-selections | grep python

Lastly, to check the details of the installed package, say python3, one needs to run
$ dpkg -s python3

That's it.