1 Add the Mono repository to your system
The package repository hosts the packages you need, add it with the following commands.
Ubuntu 18.04
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb https://download.mono-project.com/repo/ubuntu stable-bionic main" | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
sudo apt update
Ubuntu 16.04
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/ubuntu xenial main" | sudo tee /etc/apt/sources.list.d/mono-official.list
sudo apt-get update
Ubuntu 14.04
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/ubuntu trusty main" | sudo tee /etc/apt/sources.list.d/mono-official.list
sudo apt-get update
Ubuntu 12.04
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/ubuntu precise main" | sudo tee /etc/apt/sources.list.d/mono-official.list
sudo apt-get update
CentOS/RHEL 8 (x86_64)
rpmkeys --import "http://pool.sks-keyservers.net/pks/lookup?op=get&search=0x3fa7e0328081bff6a14da29aa6a19b38d3d831ef"
su -c 'curl https://download.mono-project.com/repo/centos8-stable.repo | tee /etc/yum.repos.d/mono-centos8-stable.repo'
CentOS/RHEL 7 (x86_64)
rpmkeys --import "http://pool.sks-keyservers.net/pks/lookup?op=get&search=0x3fa7e0328081bff6a14da29aa6a19b38d3d831ef"
su -c 'curl https://download.mono-project.com/repo/centos7-stable.repo | tee /etc/yum.repos.d/mono-centos7-stable.repo'
CentOS/RHEL 6 (x86_64, i686)
rpm --import "http://pool.sks-keyservers.net/pks/lookup?op=get&search=0x3fa7e0328081bff6a14da29aa6a19b38d3d831ef"
su -c 'curl https://download.mono-project.com/repo/centos6-stable.repo | tee /etc/yum.repos.d/mono-centos6-stable.repo'
其他 CentOS 7 （有点慢）
yum install yum-utils
rpm --import "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF"
yum-config-manager --add-repo http://download.mono-project.com/repo/centos/
2 Install Mono
运行环境（非开发环境）
sudo apt-get install mono-runtime
安装Mono的全部组件
sudo apt-get install mono-complete
CentOS
yum upgrade
yum install mono-complete
安装monoDevelop集成开发工具
sudo apt-get install mono-devel monodevelop monodevelop-versioncontrol