in Rebex File Server there are currently only a few simple SSH Unix-like commands that are supported out-of-the-box as 'hello', 'echo', 'whoami', 'ls', 'cd', ... To get all of them, just write "help" and a list of supported commands will pop up.
Adding support for additional commands, be it windows-like or unix-like commands is a task to be implemented by yourself. If you are running your program on a Windows machine and you want to enable users to execute Windows commands, you have advantage, as it is possible to run command prompt commands from .NET. Just start the commands via
System.Diagnostics.Process.Start method. For details see this stackoverflow post.
So you just need to write a simple wrapper class that the
ShellCommand event handler can call in case one of the custom commands needs execution and then execute it.