@bcastets
Thank you for your Answer.
I have a question:

Should I write the program (socket UR send file.py) in my main program to open or close thr robot's gripper?
but how can I do that for different commands (open once, close once, .....), do I have to change the gripper.script every time to fit my command?
For small program like: move robot, open gripper, then move robot, the close the gripper could you please write me an example?

Thank you very much!

You need to include in all URscript programs that you send to the robot over port 3002 the declaration of the functions used be gripper opening and closing commands (rq_close_and_wait(), rq_open_and_wait() ,...). You can use this article (https://dof.robotiq.com/discussion/1987/how-to-control-robotiq-product-through-port-30002-on-universal-robot#latest) as a reference.

When you execute a program on the teach pendant of a UR robot, it generate a URscript file base on the commands you have in your program tree and the URCAPs that you have installed on the robot. The URscript file contains the declaration of all functions of each URCAP followed but the main program which is equivalent to the program tree you can see in the user interface.
You can copy all URCAP functions declaration and include at the top of the URscprit that you send to port 3002 so thta you can use URCAP script functions.

You can find such URscript file by broosing the folder where you saved your program with a FTP client for example.