MAC OS: use GNU tools instead of BSD ones

The default tools of MAC OS are the BSD tools unfortunately, e.g., ls, head, etc.
I would say BSD tools are really less advanced than GNU tools, e.g., you can use "head -n -100" with GNU head, but not with BSD head, and the BSD ls is less colorful than the GNU ls.

How can we use GNU tools instead of BSD ones:

(1) install GNU tools using port:

sudo port install coreutils findutils

(2) append the following line to your ~/.bash_profile

export PATH=/opt/local/libexec/gnubin:$PATH