Remove an application

apt-get is the command-line tool for handling packages. It is used for adding / removing / updating packages.

Uninstall / Delete / Remove Package

Just use the following syntax:
sudo apt-get remove {package-name}

For example remove package called mplayer, enter:

$ sudo apt-get remove mplayer

Remove package called lighttpd along with all configuration files, enter:

$ sudo apt-get --purge remove lighttpd

To list all installed package, enter:\

dpkg --list
dpkg --list | less
dpkg --list | grep -i 'http'

sudo apt-get --purge remove libreoffice-core