Question
When I start vsftpd on my CentOs machine I get this error:
Starting vsftpd for vsftpd: 500 OOPS: unrecognised variable in config file:  anonymous_enable
How can I fix it?
Answer
The option “anonymous_enable” is a valid vsftpd option, but as you can see on the error message, there is an extra white space before the variable definition, I suspect that [...]

You can upgrade your linux system using the package manager APT which is available on debian based distributions:

First we have to update all the packages installed:
$ sudo apt-get update
$ sudo apt-get upgrade
Now we make sure that we have the update-manager-core package installed with:
sudo apt-get install update-manager-core
Then we start the upgrade
sudo do-release-upgrade

Oddly enough, PHP 5.2.6 is still not available on default CentOS repositories ([base], [updates], [addons], and [extras]), latest PHP available in those repos is PHP 5.1.6!

In order to install PHP 5.2.6 you can add the CentOS testing repository and enable it then install or update PHP.

To add the CentOS testing directory, create a file /etc/yum.repos.d/centos-test.repo [...]

This tutorial assumes that you are a sudoer running Gnome
What is .chm
Wikipedia says:
Microsoft Compiled HTML Help is a proprietary format for online help files, developed by Microsoft and first released in 1997 as a successor to the Microsoft WinHelp format. It was first introduced with the release of Windows 98, and is still supported and [...]