How can I install purchases manually, on the command line?
Sometimes it is necessary to install purchased software without using Software Center. This may happen because of a bug in Software Center, because you may be using a non-standard desktop, or perhaps because you just prefer the older ways of doing things on a command line.
To install a purchase manually, follow these steps:
Get the 'deb' line for your purchase from your subscription list. Click the title of the application from the list; the next page should display the 'deb' line.
Copy/paste the 'deb' line into /etc/apt/sources.list or into a new file in /etc/apt/sources.list.d/mypackage.list
Run sudo apt-get update
Run apt-cache search mypackage to find the exact package name. Or, copy the package name from the deb line above.
Run sudo apt-get install mypackage to install the software.
Alternately, you can navigate to your PPA subscription list on your profile at https://launchpad.net/ , browse to the package archives, then manually download the package files and install them with dpkg.