I am looking at both .bashrc and .bash_profile in order to add some things to my path. What is the difference between them? Is it preferable to use one over the other for certain situations?

I was also looking at the universal profile too (I'm adding java to my path if it makes a difference), I'm the only user on my computer, but I may well want root to have access to the same things I do. I was just a bit scared to change the universal profile because what is there already is doing some checking via if statements before adding bits to the path. I don't quite understand yet what is going on well enough to do that kind of checking. I guess it's checking to see if certain files or directories exist before adding them to the path.

Can anyone advise me on the above?

If you want root to have access too just put it in /etc/profile on a line of it's own, just don't delete anything that's already in it and you can't go far wrong

PATH=$PATH:/path_to_whatever