Linux/Mint wp-conf.php – it's locked

1. to edit it, you need to set up proper permission to wp-config.php like this:
chmod o+w /path/to/wordpress/wp-config.php
after making changes, dont forget to revert the permissions back:
chmod o-w /path/to/wordpress/wp-config.php

2. Also, you can use this command to edit it:
sudo gedit /path/to/wordpress/wp-config.php

you should have gedit installed by default in your system, probably.
if not:
sudo apt-get install gedit

you can also try other text editors this way.

The second is probably the better, if you are not that technical person and you don’t want to mess with those permissions.

Thank you for providing multiple methods. And the very thorough instructions.

I want to use the command prompt more, but I do not want to have to depend on it. Especially if I just need to get things done.

Again, big thanks. You saved me a lot of time and hassle.
Cheers!

You are correct, the gedit method is the best. Less ability to screw up, and I need to see what I am doing.

Obviously, i forgot ‘sudo‘ before chmod commands.

When using chmod, you can navigate to your wordpress folder and also open the file with the editor of your choice. But the second method I gave, is surely safer.

Oh! Thanks for that, I will correct and add to my notes.