I used the following steps;
Open a terminal and type the command below:
git clone git://github.com/phalcon/phalcon-devtools.git
Then enter the folder where the tools were cloned and execute ”. ./phalcon.sh”, (don’t forget the dot at beginning of the command):
cd phalcon-devtools/
. ./phalcon.sh
Create a symbolink link to the phalcon.php script:
ln -s ~/phalcon-devtools/phalcon.php /usr/bin/phalcon
chmod ugo+x /usr/bin/phalcon