linux

If you wish to make a backup of a file system between two unix machines, you may use scp command.

When you're working in the command-line interface, you may be going deep inside the directories and moving back and forth those directories can be a nuisance. There are built-in directory commands in ksh/bash that you can use to ease your change directory (cd) pain.

How do you use Bash Auto Completion?

A: The file and directory name completion are available by default in bash. To use the default auto completion feature of bash, you'll hit [TAB] Key once or twice.

If you have PHP version 5.4 above, you may install Xdebug with a package installer as described below. If you have a PHP version lower than 5.4, you'll have to compile the Xdebug (see instruction below).

1. Purpose

As a web host, we needed an automated mechanism for generating snapshot of server filesystems on the Linux based systems. There are a number of ways to achieve backups on Linux systems including Remote backup using Linux tar/ssh/cron and incremental tar backups on a local file system. One of the drawback of using tar to perform an entire filesystem backup is that some systems do not have an ability to create a compressed tarball greater than 2GB in size.

Our Zen Cart installation has incorrect time zone. On the orders page, the orders are placed +5 hours from current date/time. This is very annoying problem as the server is showing correct time, and PHP is configured with correct time zone in /etc/php.ini file. Also, the correct time zone is set in the includes/application_top.php file.

One of the common symptom being seen during PHP development is White Screen of Death, a blank screen instead of expected page. If you "View Source" on white page, it will often contains no title, no header or body and there are no errors - a simple blank page.

For smaller scale DDoS attacks, Web Application Firewall (WAF) like Mod Security and Mod Evasive will mitigate DDoS attacks. For larger scale DDoS attacks, you may need to turn to professional DDoS mitigation service provider.

1. Install Mod Security Apache Module.

Before getting started with nginx, it is recommended that you update PHP to the latest version.

Create a /etc/yum.repos.d/nginx.repo with the following content:

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

We are going to use php-fpm package to handle PHP fast-cgi.

Keeping your Linux server up-to-date with the latest packages is no small task. One of the most popular repository for RHEL, Centos and Scientific Linux among others is EPEL, Extra Packages for Enterprise Linux. EPEL is a Fedora Special Interest Group that creates, maintains, and manages a high quality set of additional packages for Enterprise Linux.

If you wish to upgrade your PHP, MySQL and HTTP to the latest available binary packages, you may opt to install EPEL and remi repositories on your linux system.

On Centos 6.x:

Apache is the most popular web server being used today. Apache Killer exploit which was released in August 2011, exploits a vulnerability in the Apache software by sending a crafted "Range" HTTP header. Apache Killer attack abuses the HTTP protocol by requesting URL content to be returned in a huge number of small chunks, which leads to hundreds of large memory fetches causing a server to run out of memory and crash. This vulnerability identified as CVE-2011-3192 was fixed in httpd-2.2.21.