How to uninstall a .deb package?

Manually installed packages appear in the Software Centre, along with all the others. Just search the software centre for your package and remove it there.

You may have to click on "Show N technical items"

Along with this, there are a few other methods:

Synaptic:

• Go to System → Administration → Synaptic Package Manager
• Click the Status button and select "Installed (local or obsolete)"
• Right click a package and select "mark for removal".

• Click the Apply button.

  This will have the benefit of listing all of your manually installed packages:

Command Line

• You can either use sudo apt-get remove packagename if you know the name of the package, or if you don't, search for it using apt-cache search crazy-app and then remove it using apt get

• You can also use dpkg --remove packagename.

This will also let you know if there are any unneeded packages left on your system, which were possibly installed as dependencies of your .deb package. Use sudo apt-get autoremove to get rid of them.

The command to facilitate that is:

sudo dpkg -r package_name

Also if you need to remove them forcefully

sudo dpkg -r --force-all pkg_name

Every solution here assumes you know or can find the name of the package, but none provide how to remove a package if all you have is the deb. To that end, the below command will extract the package name from the deb and remove that package name.

dpkg -r $(dpkg -f your-file-here.deb Package)

NB: this does not confirm that the package being removed is the exact version described by the deb - be careful.