How to add variables in a batch file. Ask Question Asked 7 years, 11 months ago. Active 3 years, 6 months ago. Viewed 19k times 2. I'm trying to get a list of numbers. Feb 25, 2020 A file with the.BAT file extension is a batch processing file. It's a plain text file that contains various commands used for repetitive tasks or to run groups of scripts one after another. Software of all types use.B..