You can create, edit and run scripts using Fiji's script editor. For details, please see [[Using the Script Editor|the Script Editor documentation]].
Creating scripts and using "refresh scripts" =
On startup, ImageJ will run all "refresh scripts" plugins, one for each supported language. This will result in all scripts present within the plugins folders to be added to the menus .
To run a script, just select it from the plugins menus.
If you edit a script that is already placed in the menus, you don't need to do anything else: just save the text file and run it again by selecting it from the menus.
If you add a new script and ImageJ is running, just go to Plugins - Scripting and run the appropriate Refresh * Scripts for the language.
== Running scripts in headless mode ==