How to trim fields during converting file from xlsx to csv

At the moment we are converting the xlsx file to csv in headless mode
There are fields in the file which are super long and we need to trim them to a fixed length

Is this possible in headless mode?


see the answer to the following question Updating table of contents TOC with command line. Though the question is about Writer, the same principle applies here: Conversion using --convert-to does not support any document changes. The intention of --convert-to is to get as close as possible to the original document. You need to change the document to a version, which fits your needs before you use --convert-to. And this probably means that you need to write user code (macro)

Hope that helps.