Depending on the platform (Windows, Linux, macOS), the launching of a demo can vary. There are two main methods:
The first method is available on all platforms (Windows, Linux et macOS) since GeeXLab 0.25.3.0. The second method is available on all platforms.
It's the easiest method for launching a demo: just start GeeXLab and drag-and-drop any XML scene filew from the file manager (Explorer for Windows, Finder for macOS, etc.) into GeeXLab. Here is the drag-and-drop in action on Raspberry Pi:
On Windows and macOS, you can also launch a demo from GeeXLab user interface: just go to Menu > File > Load scene file (keyboard shortcut CTRL+O).
If you have done changes in the demo source code, just reload it with the following shortcut: CTRL+R (or via the menu: File > Reload scene file).
The command line is not the easiest method but it's a powerful one. And this method is available on all platforms. Let's see how to use the command line for each platform.
For every platform, I suppose a terminal is open in GeeXLab root folder and that we want to run a demo called my_demo.xml stored in GeeXLab demos/ folder.
open 'GeeXLab.app' --args '/demofile="./demos/my_demo.xml"'
Here the Linux platform can be the regular Linux (Ubuntu, Linux Mint, etc) as well as the Raspbian (Raspberry Pi) and Tinker OS (ASUS Tinker Board) platforms.
We can also store the command line in a .sh file. In that case for macOS and Linux, do not forget to add #!/bin/bash in the first line of the .sh file.
#!/bin/bash ./GeeXLab /demofile=\"./demos/my_demo.xml\"
You can launch this file from the command line with:
$ sh ./start_demo.sh