newly installed shell aps not working without full paths

Hello I have a very strange problem that happened on my new macbook. It seems that whenever i install some app thats for the shell or mac terminal it doesnt work unless u type in the full path. A few examples of this are fink in that if I just type in fink it says comand not found so then I have to type the full path /sw/bin/fink. There are a bunch of programs like that dont work in the same including unrar. Now I know from linux that u need to have the path in your environment varable but how do u add all the programs in /sw/bin to it on osx?

Interestingly enough it worked on my last install of os x automaticly were i could just use the comands without the full paths. Then after i reinstalled os x to save on some space this problem developed. Hope someone can help.