How to install Asterisk on Lubuntu.

Install Asterisk on lubuntu-12.04 (64Bit)

Install related packages. 
sudo apt-get install build-essential
sudo apt-get install php5-mysql libapache2-mod-php5 mysql-server libmysqlclient15-dev php-db   php5-gd php-pear sox curl g++ libncurses-dev libxml2-dev subversion



Download Asterisk:
 wget http://downloads.asterisk.org/pub/telephony/certified-asterisk/releases/certified-asterisk-1.8.15-cert5.tar.gz
 tar -zxvf certified-asterisk-1.8.15-cert5.tar.gz 
 cd certified-asterisk-1.8.15-cert5

Install Asterisk:
  ./configure
  make
  make install
  make config
  make samples

Test Asterisk:

Go to terminal (Command Prompt)

asterisk -r


It will work.