Unfortunately, no one can be told what Sh Matrix is. You have to see it for yourself.
jonty@towel:~$ cd a_virtualenv/project
(a_virtualenv)jonty@towel:~/a_virtual_env/project$ cd ~
jonty@towel:~$ cd another_virtualenv
(another_virtualenv)jonty@towel:~/another_virtualenv$ cd /tmp
jonty@towel:/tmp$
Because that was indecipherable line noise. Let's try again.
Sh Matrix is a microscopic script that automatically activates and deactivates Python virtual environments, regardless of where virtualenv put them, or how they're laid out.
Think of it as a less prescriptive virtualenvwrapper for people who think that ~1000 line bash scripts should be shot in the face.
Depending on preference, you can either bung the entire script into the end of your ~/.bashrc, or you can source it.
curl https://raw.github.com/Jonty/Sh-Matrix/master/shmatrix.sh >> ~/.bashrc
Or
curl https://raw.github.com/Jonty/Sh-Matrix/master/shmatrix.sh -o ~/.shmatrix.sh
echo -en "\nsource ~/.shmatrix.sh" >> ~/.bashrc
Obviously you'll have to source ~/.bashrc
or restart your shells. But then you knew that, didn't you?