https://blog.csdn.net/qq_21153619/article/details/81459359 这样应该比较简单
yum方式按照mono
rpm --import "http://keyserver.Ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF" yum-config-manager --add-repo http://download.mono-project.com/repo/centos/
#如果提示没有yum-config-manager命令，需要安装yum-utils
yum -y install yum-utils
正常安装的命令为:
yum install -y mono