Run only the commands without the Number sign (#), its not a script. This is thing that should be read...

gistfile1.txt

# Install libxml2 using Homebrew
# If you don't have Homebrew, follow the instructions at:
# https://github.com/mxcl/homebrew/wiki/Installation
# -------------------------------------------------------
brew install libxml2

# Install libxslt from source code
# If you don't have wget, follow the instructions at:
# http://www.mactricksandtips.com/2008/07/installing-wget-on-your-mac-for-terminal.html
# Or use Homebrew:
# brew install wget
# -------------------------------------------------------------------------------------
wget ftp://xmlsoft.org/libxml2/libxslt-1.1.26.tar.gz
tar xvfz libxslt-1.1.26.tar.gz
cd libxslt-1.1.26
./configure --prefix=/usr/local/Cellar/libxslt/1.1.26 --with-libxml-prefix=/usr/local/Cellar/libxml2/2.7.8
make
sudo make install

# Install libiconv using Homebrew:
# --------------------------------
brew install libiconv
sudo brew link libiconv

# Install the Nokogiri gem passing in all the dependency paths:
# -------------------------------------------------------------
gem install nokogiri -- --with-xml2-include=/usr/local/Cellar/libxml2/2.7.8/include/libxml2 --with-xml2-lib=/usr/local/Cellar/libxml2/2.7.8/lib --with-xslt-dir=/usr/local/Cellar/libxslt/1.1.26 --with-iconv-include=/usr/local/Cellar/libiconv/1.14/include --with-iconv-lib=/usr/local/Cellar/libiconv/1.14/lib