How to convert .dat files to .csv? Right-click on the DAT file > Open with > Notepad. Next, save the Notepad TXT file as a CSV file, using the Save as option and giving it a .csv extension. Now ...

If you need to convert that file from CSV to JSON, you can do that with the csvjson command like so: csvjson clients.csv > clients.json Csvkit has a couple of other handy tricks up its sleeve.