I read a lot of articles and information regarding my questions, but those answers were very technical and I wanted to understand the law in simple English.
https://tldrlegal.com/license/gnu-general-public-license-v3-(gpl-3)(GPL3) Version Information
As per above Link, I can commercially use the software.
I have modified in GNPL GNU Application and selling it to my customer for a fee via a Web Portal. I will include a Copyright and also License copy of original software which I used. Is the enough? My Problem is disclosing the upgraded code, I am ok sharing with people when they justify me a reason to get free access to upgraded code over an email, but I do not want to simply publish the code over the web or URL for the world to see, because check below
Imagine two situations which support my above line.
1)My competitors can copy the same code and resell, then my investment for customization goes into the drain. 2)As per TDRLegal, I can even claim a patent for the upgraded product going future or I can we are inspired for X Open Source Software and charge for the upgrade as one time free.
This is a situation which most of the small startups have faced and wanted to know if there is a workaround the law, where we can use the open-source at the same time stay compliant with the legal law and protect our investment made over time by customizing the open-source software.
Please suggest the best actions.