Editing certain lines in a file that's on a CentOS server through a web interface

This is my second post on here, if there is something essential I missed out on in the post, feel free to give me feedback so I can improve it for the next one! Now, to my problem.

I want to create a web interface where people can enter a couple different strings which will be entered into a certain lines in a file on a CentOS server. I would just like to know where I should start with this, which language is most appropriate etc. If someone could point me in the right direction on how to do this, I would be most greatfull!

Thanks in advance :)