Installing R on Mint

Well, you start here and click all the way to here but then, I didn't know which to choose

INSTALLATION
To obtain the latest R packages, add an entry like
deb http://<my.favorite.cran.mirror>/bin/linux/ubuntu raring/
or
deb http://<my.favorite.cran.mirror>/bin/linux/ubuntu quantal/
or
deb http://<my.favorite.cran.mirror>/bin/linux/ubuntu precise/
or
deb http://<my.favorite.cran.mirror>/bin/linux/ubuntu lucid/

So it turns out that raring, quantal, precise etc are names of Ubuntu packages (duh). Googeling 'linux version' got me here so my Linux Mint Maya corresponds to precise!

Now I added

deb http://www.freestatistics.org/cran/bin/linux/ubuntu precise/

to

/etc/apt/sources.list

then

sudo apt-get update
sudo apt-get install r-base 

and it's done.

Grab screen color utility on Linux

The following link provides a super basic command line utility for grabbing the hex and RGB color codes of any pixel on your screen.
After installation just type

> grabc

Your cursor then becomes this little + that can placed anywhere on your screen and when you click the mouse button you get the hex and RGB value of the color of that pixel.

Example:

Upgrade ruby with RVM

rvm get stable
rvm list known

now pick the one before HEAD, say it is -p247

rvm install ruby-2.0.0-p247

After that rspec spec crashed with :

`require': no such file to load -- rubygems

The solution is to run

rvm use

which apparently solves the ambiguity between several installed ruby versions

Rspec fails to run after bundle update

Turns out that the problem goes away if you change

gem 'selenium-webdriver', '2.0.0'

to

gem 'selenium-webdriver', '~> 2.35.1'

as was mentioned here