PHP Tutorials & HowTos

PHP is an open-source server-side scripting language and one of the most popular in web development. This section includes PHP programming related syntax, questions and answers ( rss feed ).

I‘m using GeSHi under php to highlight a source code. How do I turn on or off line numbers using GeSHi?


How do I find out php version under Linux operating systems? How do I find out php version under Unix like systems? How to find out what version of PHP is installed on my server?

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I‘ve recently installed php 5.3.5 in my UNIX box and my old working php code not working. It displays code in pages which is in <? … my code … ?> php tags. How do I fix this problem?


I‘m getting the following errors in my log file whenever I use phpinfo() function:

[10-Jan-2011 18:39:08] PHP Warning: phpinfo(): It is not safe to rely on the system’s timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected ‘America/Chicago’ for ‘CST/-6.0/no DST’ instead in /home/servers/http/dev/testpc.php on line 2

How do I fix this problem under UNIX / Linux php running Apache or lighttpd web server?


How can I compare two strings using php? How do I use php to compare two strings?


Our customer support wiki runs on an internal host (ip:, hostname a-node100.:300) and it is behind the nginx reverse proxy server. However, our Apache server end up displaying internal server name http://a-node100.:300/, which results into an unexpected redirection and timeouts as http://a-node100.:300/ is not accessible over the Internet. How do I force nginx or apache to use the base URL of our server (

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Recently, we moved all our static assets to a CDN as described here. However, we have over 8000+ old blog posts and we need to point static images url to our CDN account hosted at folder. How do I rename all image urls stored in wordpress posts? How do I offload static images to a CDN urls under Wordpress?