Debugging with scripting language is different with programming language. You need special tool to debugging in scripting language. In PHP we can use xdebug to increase verbosities of PHP.

I assume apache2 and php5 is installed and working well, and here's how we install xdebug in ubuntu thanks martin_lindhe and Jarrod Nettles

Jarrod Nettles version

Step 1

Install xdebug with apt-get

sudo apt-get install php5-xdebug

Step 2

In my ubuntu (Saucy Salamander 13.10) file xdebug.so placed in /usr/lib/php5/20110331/xdebug.so so you need to add this line to the end of this /etc/php5/apache2/php.ini

zend_extension="/usr/lib/php5/20110331/xdebug.so"

Make sure that html_error is on. Find this line in /etc/php5/apache2/php.ini

html_errors = On

Step 3

Restart apache with this command

sudo service apache2 restart

or

sudo /etc/init.d/apache2 restart

martin_lindhe version

martin_lindhe use pecl approach.

Step 1

Install php5-dev and php5-pear via apt-get

sudo apt-get install php5-dev php-pear

Step 2

then install xdebug via pecl

sudo pecl install xdebug

Step 3

Find xdebug.log location and add it into end of file /etc/php/apache2/php.ini file

asep@thinkblack:/$ find / -name 'xdebug.so' 2> /dev/null
/usr/lib/php5/20121212/xdebug.so

Step 4

Restart apache with this command

sudo service apache2 restart

or

sudo /etc/init.d/apache2 restart