how to open an application from terminal in ubuntu code example

Example 1: ubuntu open directory from terminal

xdg-open folder_name

Example 2: how to open any application using terminal

ou can just type the the name of the application you want to start. 
In your case it would be libreoffice or if you want to go to writer 
directly you can type  libreoffice --writer

Example 3: how to install programs in ubuntu using terminal

wget https://dl.google.com/linux/direct/google-chrome-stable_current_i386.deb
sudo dpkg -i google-chrome-stable_current_i386.deb