How do I update DrRacket?

Question

I installed DrRacket with the Software Center, but it only installs the verion 5.2.1. I downloaded the installer from the website http://racket-lang.org/download/

I just started using ubuntu... and after a bit of searching I found out how to install .sh files:
First:

chmod +x filename.sh

Second:

./filename.sh

Then the terminal asks me if i want to install the Unix-style distribution, I type in yes.
After this the terminal says:

Where do you want to base your installation of Racket v5.3.1?
(If you've done such an installation in the past, either
enter the same directory, or run 'racket-uninstall' manually.)
1 - /usr/... [default]
2 - /usr/local/...
3 - ~/... (/home/julian-b/...)
4 - ./... (here)
Or enter a different directory prefix to install in.

I choose the default one (1) and I get the following...
Error: The entered base directory is not writable: /usr

How do I make my filesystem or /usr writable?

Answer 1

I think the only thing you forgot was to give the program root permission so It can install, to give program the permission you use the command sudo, then you will be prompt for your login password.

The commands should look like this

sudo chmod +x filename.sh

or

sudo ./filename.sh