Glu can run pretty much any Lua script, not just those that use Glu's built-in functions. If a script calls the standard print or io.write functions then Glu automatically opens a console window to display the output. For a simple example, run console.lua.
To abort a lengthy console script you can hit the escape key or click on the Stop button at the top of the console window. When the script ends the button changes to Run in case you want to run the same script again. To try the Stop button, copy the following line and select Run Clipboard from the File menu:
The console window is automatically closed when you run a new script. Manually closing the console window will abort a running script.
Note that the console can be cleared by calling print().