[deleted] I've typed nickname root and password root, and I get Login incorrect.
Believe me ... I'm a retired software engineer, not an amateur. You DO NOT need to use sudo or log in as root in order to edit a file in your own home directory, or any subdirectory of it. That's just how Linux (and Unix) works.
You've gotten a lot of incorrect advice in this thread, and that's got you trying more things that won't work.
If your object is to remove something you previously added to a file in your home directory, you only need your ordinary user name and password that you used to log on. You will, by default, start out in your home folder. So the entire command to edit something in .profile there will be: nano ./.profile.
It's unlikely that you've changed to another directory after logging in, but if you've done that for some reason, you'll need to add a tilde (~) to your command: nano ~/.profile.
If you use this second version of the command and you're already in your home directory, it will still work perfectly. I don't want to complicate this by explaining why. Just trust me for now, and ask me about it after you've gotten things working. I'll be happy to explain why ~/ and ./ sometimes mean the same thing.
