Author: Hidden User

How to Mirror A Directory Locally Using Rsync

Most of the instructions for mirroring a directory with Rsync involve mirroring the data to a different server. You can also use Rsync to sync or mirror a directory on the same computer as the source directory.

Here is an example command on how to mirror two directories locally. In this example, /home/apache/public_html is the source directory and /home/apache/public_html_bak is the destination directory. Forward slashes at the end of the directory names in the rsync command are important so don’t forget them. The sync is one-way in that the destination will mirror the source:

rsync -avr --delete --links /home/apache/public_html/ /home/apache/public_html_bak/

If you need to preserve ACLs and Extended attributes then you need to add the -A and -X switches:

rsync -avrAX --delete --links /home/apache/public_html/ /home/apache/public_html_bak/

If you want to just do a dry run to see what will happen when you run Rsync, then add the -n switch:

rsync -avrAXn --delete --links /home/apache/public_html/ /home/apache/public_html_bak/

Terminal






	


	
	






	
	

		
How to Block an IP Address Using Firestarter
	


	

		
Firestarter is a GNOME program which offers a GUI interface to the IP Tables firewall.


If you have Firestarter configured to allow all IPs addresses to all ports or a particular port on your server, you can’t block a specific IP from accessing those ports using the GUI interface. However, Firestarter does allow you to manually specify IP Tables rules to either load up BEFORE or AFTER the Firestarter firewall rules by editing configuration files. On CentOS 5, the file to put the rules you want to load before Firestarter’s rules is /etc/firestarter/user-pre. For rules you want to load after Firestarter loads its firewall rules, edit the file /etc/firestarter/user-post. When you add your rules, instead of using the command “iptables” you need to use the variable name “$IPT” instead. To block an IP address from accessing any of your ports, you will need to add the IP Tables rule to the user-post file.


For example, say you want to block the IP address 123.11.112.1 from accessing your server on any port. The normal IPTables rules for this is:


iptables -I INPUT -s 123.11.112.1 -j DROP


To make this rule work with Firestarter, add the following line to the /etc/firestarter/user-post file:




$IPT -I INPUT -s 123.11.112.1 -j DROP




After you edit the user-pre or user-post files, you have to restart the Firestarter service to put them into effect. On CentOS 5 you can run the following terminal command to restart the Firestarter service:




service firestarter restart




Firewall Hole

	


	
	






	
	

		
How to Not Update a Package From a Specific Repository Using Yum
	


	

		
If you are using Yum to manage packages from multiple repositories it may be beneficial for you to not update a particular package against a specific repository in favor of another one. To do this, simply add the following line to the Yum configuration file for the repository you want to ignore:


exclude=packageName1 packageName2 packageName3


For example, say in CentOS 5 you wanted to not update the php-pecl-mailparse package against the Epel repository. You would edit the file /etc/yum.d/epel.repo and add the exclude line like so:


[epel]
name=Extra Packages for Enterprise Linux 5 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/5/$basearch                 
mirrorlist=http://mirrors.fedoraproject.org/mirrorlist?repo=epel-5&arch=$basear$
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL
exclude=php-pecl-mailparse

...


Terminal

	


	
	






	
	

		
How to Determine How Many Inodes the Current Directory is Using
	


	

		
Some web hosting providers have a limit on how many inodes you can use. Here is the shell command to display how many inodes the current directory you are in is using:


find . -printf "%i\n" | sort -u | wc -l


If you don’t have shell access to your web server, you can do the same thing with a PHP web page. Just place this web page in the directory that you want to know the number of inodes it is using and access the PHP web page from your web browser. The PHP code to put in the web page file is:




<?php
  echo "<b>";
  system('pwd');
  echo "</b>: ";
  system('find . | wc -l');
  echo " inodes<br />\n<b>";
  system('cd ~/public_html; pwd');
  echo "</b>: ";
  system('cd ~/public_html; find . | wc -l');
  echo " inodes<br />\n<b>";
  system('cd ~; pwd');
  echo "</b>: ";
  system('cd ~; find . | wc -l');
  echo " inodes";
?>




Terminal