Archive for the 'Linux' Category

Fedora Quick Tip: Resolving Permission Denied Issues in HTTP and FTP services with getsebool and setsebool

If you are running Fedora Linux as a server, one issue you frequently encounter is strange permission denied error message triggered when you are accessing one of the available network services run on the server. There are a lot of network services to mention, but HTTP and FTP are two good examples of such services. Assume you are trying to access FTP server on your Fedora box. You type the IP address of the server and then supply the username and password. Voila!!! You thought you would be immediately logged in. But instead of seeing the files in your home folder, you are shown an error message. The error message may vary, from something like “Login incorrect for user blah” displayed by Midnight Commander, “500 OOPS: cannot change directory: /home/blah” from Total Commander, to other error messages shown by different FTP client programs.

If you are 100% sure that you supply the correct user and password information, why couldn’t you get in? Let us assume that you have root access to the server so that you can remotely troubleshoot from the console. This post will give some guide on how you can solve this problem based on common configurations of a Fedora server.
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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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Quick Tip: Installing MySQL on Fedora Linux

Installing MySQL on Fedora has never been easier than before. If you are a first timer who wants to know how to install MySQL on a Fedora server or desktop, follow this guide to successfully install both MySQL client and server only in three steps.

Before you proceed to the installation, the environment settings for the snapshot pictures of the installation are provided below:
OS: Fedora 13 64-bit
Prerequisites: yum is installed, commands invoked on root shell
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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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Sizzling Upload Progress Bar in PHP with APC, Part 1: APC Installation

After some series of “political” technical notes, I think it’s the right moment to supply some more technical posts to fellow developers. This time I will write about creating sizzling upload progress bar in PHP. In the past, there had been heated debate in PHP internal list about RFC 1867 implementation on PHP core code. If you were there, you might still remember that we had to patch the file main/rfc1867.c and some other files and then recompile PHP to get the upload progress bar hack working. Some harsh critics even mentioned that without the built-in capability of upload progress, PHP was years behind Java and Perl and lacked its capability as a web programming language.

Fortunately, since PHP 5.2 (especially after PHP 5.2.6 release), showing upload progress is not a big deal in PHP. Thanks to APC developers -mostly are also core PHP developers- who contributed to changes in APC that led to the availability of this long-waited feature. With APC we’ll be able to track the progress of file upload and provide our users better convenience when using our application.

Still, APC is not a part of core PHP shipped as a bundled package. We need to install it manually. In Windows, we can simply load the dll file to get it working. However, Linux users may need some pointers about how to install and enable this package. Hence, I will provide some guide for APC installation which was tested on veteran RHEL 4 and energetic young Fedora 10. So, let’s just go to the installation part. Continue reading