1. Open to edit .bashrc
pico ~/.bashrc
2. Print following
PATH=$PATH:some_path export PATH
3. Save .bashrc
4. Run .bashrc
source ~/.bashrc
It` done, you can look, what is in your Path:
echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games/:some_path