Hi,

I would like to know if is it is possible to run a Processing script in batch mode, i.e. non-interactively, trough a command line, without any active display on screen.

This could be useful for me to integrate processing in a production environment running on a remote HPC cluster. (by the way, I am using Linux). For example to post-process automatically the frames of a video, saving the post-processed sequence of images in a storage.

I am not expert in java at the moment, so maybe I have posed a stupid question.

Thank you.

Wow, you know, I had the same question!  And apparently 123 people
have viewed this post since Jan 15.  It seems to be a popular question.
Perhaps a more detailed answer might be made available to those
of us who are new to Processing?

It seems somewhat strange to me that ./processing --help doesn't explain
this question directly.

Thinking more about it, I don't think that Commander allows you to do headless processing (sic) power... (but I can be wrong).
The core of Processing code is PApplet, which, as the name implies, is an applet, something made to run in a browser, but that can be run standalone.
But it is designed to display a window in all cases. When I do a quick graphics-less sketch (eg. println("Info")), I still have the default display, I have to get rid of it by calling exit() at the end.

So, if I am not mistaken, to make a headless Processing, one would need to take the source code of PApplet and hack it to remove references to java.applet.Applet (and usage of keyboard, mouse, scanning display characteristics, etc.).
Ie. it would need an alternative Processing application. Not very hard to do if you know Java a bit...

[EDIT] Searching headless in shows this old thread: Server-side image generation. Basically, fry confirms my observations...
On the other side, in Processing on EC2, OP mentions using Xvfb (virtual frame buffers) to simulate display on a headless server. I don't know more about that...