Cloud9 may be for C# development, but by default the Mono C# development environment is not installed. This is indicated by the following error when running a .cs file:

bash: line 1: ...: No such file or directory

To install Mono and the C# compiler on Cloud9, enter the following commands at the bash prompt. If you don't see a bash prompt, open a New Terminal window.

sudo apt-get update
sudo apt-get -y install mono-complete

Then add a new runner for C# files with the following configuration. Save the new runner as

  "script": [ 
    "mcs \"$file_name\"",
    "mono \"$file_base_name.exe\""
  "info": "Compiling $file_name and running $file_base_name.exe",
  "selector": "source.cs"

See Also