Install Mono and MonoDevelop

Add additional package repositories. First add the Mono Project GPG signing key by typing in the (remote or local) command prompt

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

Then type

echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list

for the first repository. Now enter

echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | sudo tee -a /etc/apt/sources.list.d/mono-xamarin.list

for the second repository.
Once added, we need to execute the sudo apt-get update and sudo apt-get upgrade commands again. Cool, now we are finally ready to install Mono: enter

sudo apt-get install mono-complete

When prompted hit enter or Y to confirm the installation of the complete Mono framework. Give it some time to complete, it takes like 5 minutes.

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