Hi,
I've done a lot applications like this one. I will program in C# (.NET), deliver a fully functioning (and tested) software along with the source code.
I just need to get some more details from you.
As far as I'm aware:
1. The application will allow the user to load a single text file (*.txt) which contains around 2M lines of text, each contains a short sentence
2. There will be a tool in the application allowing the user to delete duplicate lines. A duplicate line is the same characters as another line regardless of the character case. Later lines will be deleted
3. The lines will be displayed inside the application interface for scrolling.
4. The user can type some text in a text box, then the application will filter the lines of text to show only those lines which contain the input text
5, I don't understand "ability to save sorts to pc"
Please correct me if I'm wrong, and please clarify the point I don't understand.