Archive for the 'Programming languages' Category

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Sample PHP Application: A Simple PHP Command Line-based File Generator

PHP is a great scripting language to build web applications. Reckoning my first exposure to the language, I have been tinkering with PHP for some years by now. Despite the sluggish improvement and development towards a more architecturally robust, more feature-rich, and less quick-and-dirty programming language recently, I still love coding bytes in PHP. Some people may think of PHP as the language for programming the web quickly. Write some HTML, embed some javascript, add some CSS, put some PHP code, and voila… a dynamic web page is created. I won’t praise how good PHP is for developing a web application. Several companies may have done that. Name Facebook and Yahoo as examples. With some optimization to native PHP codes, both companies have shown how to use the language to cater to millions of users and run a serious business.

In this post, I’d like to highlight another feature of PHP, the command line interface (CLI). In my personal experience, PHP CLI can be an alternative to some administrative tasks. Linux users may have been familiar with shell scripting for carrying out system management and configuration tasks. So, why must PHP? The answer is portability. The same PHP code should work not only on Linux but also on Windows. Some critics may argue that other languages may also have answer for portability. I concur to that criticism while at the same time emphasizing PHP as another viable option.
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Quick Tip: How to Install and Configure PHP in Fedora Linux

Previously, I have discussed about how to install MySQL on Fedora Linux. In this post, I would like to elaborate PHP installation on Fedora. Even though the installation is simple by nature, I would like to provide some notes to help you troubleshoot some post-installation problems that may occur.

As usual, I will provide the screenshots of the installation along with the commands invoked on the terminal. For the environment, some important settings are written below:
OS : Fedora 13 64-bit
Web server : Apache HTTP Server
PHP version : PHP 5.3.2
Constraints : yum is installed, commands invoked in root shell, Apache is already installed and running

Note: Apache is installed by default in Fedora. You only need to configure and verify that the server is running. How to configure Apache is explained in the online documentation. If you want the server to be public, i.e. accessible from other computers in the network, you should not firewall the HTTP port, which is usually port 80. Also, if you enable selinux, you also need to properly set the flag of some security parameters related to http. I will explain about selinux and http in another post.

Now, let’s move to the installation. Basic installation steps are as follows:
1. Install PHP via yum
root# yum install php


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Eclipse Quick Tip: Resolving Error “The import javax.servlet cannot be resolved”

When you start to develop web application using Java, you may think to use Eclipse as the IDE. Assume that you have seen a good tutorial about Java servlet on the internet or read the chapter of a book discussing about web development using JSP.

You are now writing the first servlet by using the wizard provided by the IDE. However, as soon the template file is loaded on the source code editor, you encounter the infamous error “The import javax.servlet cannot be resolved” just like depicted in the figure below.

Servlet import error

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Quick Tip: Configuring Eclipse to Run for the First Time

Eclise GalileoFor Java developers, Eclipse is a convenient tool to develop software in broad range of programming languages. This tip is intended to help fellow developers who never use Eclipse before but are eager to start developing applications using Eclipse IDE.

Even though Eclipse is cross-platform, there is no guarantee that the tip provided in this post will also work for version of software and environment other than ones described below:

  • OS: Windows
  • Eclipse version: Eclipse 3.5 Galileo
  • JDK version: Java EE 6 SDK

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Comprehensive Guide to Java (JRE and JDK) Installation on Fedora Linux – Tips and Tricks

Sun's Java JRE and JDK on FedoraIn this article, you will be exposed to the installation of Sun Java in Fedora Linux. Although Java has been installed by default in every fresh Fedora package, the Java version shipped along with the OS package is the open-source version GNU Java instead. Some applications and frameworks may require Sun Java. Due to licensing issues, however, Sun Java can not be bundled with the default Fedora Linux package and should be installed separately. Although the installation steps in this article can also be reproducible in other Linux distributions, there is no guarantee that steps advised in this article will also work for other Linux distributions.

The installation of Sun Java in a Fedora Linux box can be seamlessly easy. Yet, some people especially those with minimum technical experience on *NIX OSes may face difficulties in completing the installation. This article tries to provide a comprehensive guide for the installation. It provides whole steps to be followed along with corresponding snapshots so that one can accomplish the installation successfully. It also shares some useful tips which may help readers in understanding the environment they are working on better.

Prerequisites and constraints

This installation assumes that the following requirements and constraints have been fulfilled:
1.    Installation will be conducted through the console prompt.
2.    User conducts the installation using root account.
3.    The software yum must have been already installed in the box.
4.    The software wget is already installed in the box.
Tip: if wget is not installed yet, run command yum install wget from the console and the software will be immediately installed.
5.    Fedora version used is Fedora 8.0 or newer.
Note: in legacy Fedora, there is different path in installing the compatibility libraries. You can check jpackage site for more information.
6.    JRE and JDK version to install is 1.6 (snapshots are for JRE and JDK 1.6 update 17)
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