How can I get commands written in ubuntu prompt as JSON file.

You can't store commands given to the command prompt as anything, unless those commands are either typed into your app, or execute your app - to do anything else would require a keylogger, and we aren't about to start helping with those!

If you are after the command line that executed your code, it's simple - it's passed to the startup method ("main" for a console based app) as the arguments. You can do what you want with that including write it as JSON data where ever you like!

If you are after data typed into your app then that's entirely up to you: how you store it is your decision, but since JOSN is a hierarchical store we can't just give you exact code because we have no idea what the relationship between the data items might be, and that';s essential for organised data (but irrelevant for a log file or "flat text" storage).

Have a think about exactly what you are trying to do and why: your question doesn't read like you are sure, but are just trying to code something by "guess and hope" and that never works well! :laugh: