Sometimes we need to run some system commands from  within our program. In such cases the following example can be helpful.

<%-- Button in aspx file --%>
<asp:Button ID="btnCommand" runat="server" Text="Button"
        onclick="btnCommand_Click" />

If you click on the button the following event handler will be called and the command line interface would be executed.

// Event handler
    protected void btnCommand_Click(object sender, EventArgs e)
    {
        System.Diagnostics.ProcessStartInfo objProcessStartInfo =
                                                        new System.Diagnostics.ProcessStartInfo("CMD.exe", "/C " + "dir");
       
        // CMD.exe is the name of the file which will execute.
        // /C is the path name.
        // dir is the command which will execute in command prompt.

        objProcessStartInfo.CreateNoWindow = true;     // This line will not create any new window for command prompt.
        objProcessStartInfo.UseShellExecute = false;  
        // Set  UseShellExecute to specify whether to start the process by using the operating system shell.
     
        System.Diagnostics.Process objProcess =
                                     System.Diagnostics.Process.Start(objProcessStartInfo);
       
        objProcess.Close();
    }

The above example will open the command line interface, but it will not be visible. If you want to make the command prompt visible then assign false to objProcessStartInfo.CreateNoWindow.