Installation on Debian 8

apt-get update
aptitude install xfonts-base xfonts-75dpi fontconfig xvfb
mkdir ~/src/wkhtmltopdf -p
cd ~/src/wkhtmltopdf
wget https://bitbucket.org/wkhtmltopdf/wkhtmltopdf/downloads/wkhtmltox-0.13.0-alpha-7b36694_linux-jessie-amd64.deb
dpkg -i wkhtmltox-0.13.0-alpha-7b36694_linux-jessie-amd64.deb
echo 'xvfb-run --server-args="-screen 0, 1024x768x24" /usr/local/bin/wkhtmltopdf $*' > /usr/bin/wkhtmltopdf.sh
chmod a+rx /usr/bin/wkhtmltopdf.sh
ln -s /usr/bin/wkhtmltopdf.sh /usr/local/sbin/wkhtmltopdf
/usr/local/sbin/wkhtmltopdf https://www.google.fr output.pdf

Installation on Debian 9

apt-get update

apt-get install wkhtmltopdf xvfb xauth xfonts-base xfonts-75dpi fontconfig
echo 'xvfb-run --server-args="-screen 0, 1024x768x24" /usr/bin/wkhtmltopdf $*' > /usr/bin/wkhtmltopdf.sh
chmod a+rx /usr/bin/wkhtmltopdf.sh
ln -s /usr/bin/wkhtmltopdf.sh /usr/local/sbin/wkhtmltopdf
/usr/local/sbin/wkhtmltopdf https://www.google.fr output.pdf

Installation on CentOS 6

$ wget http://wkhtmltopdf.googlecode.com/files/wkhtmltopdf-0.9.9-static-amd64.tar.bz2
$ tar xvjf wkhtmltopdf-0.9.9-static-amd64.tar.bz2
$ mv wkhtmltopdf-amd64 /usr/bin/wkhtmltopdf

// In case you got the issue
// wkhtmltopdf: error while loading shared libraries:
// libfontconfig.so.1: cannot open shared object file: No such file or directory
//
// run the command below:

$ yum install urw-fonts libXext libXrender fontconfig libfontconfig.so.1