How to take Screenshot in OS X (Mac)

There are different methods for taking a screenshot in windows and Linux OS. But macintosh machines with  OS X has an inbuilt mechanism where in one can take a screenshot.
Depending on the keyboard used, the keystrokes may vary.

Screenshot of entire screen
If you are using Apple Keyboard the combination is Command+Shift+3 keys together pressed and released. Once the keys are released, the screenshot will be stored in the desktop itself.
If you are using Conventional Keyboard for Macs (Ex: For Mac mini, etc), the key combination is
Window  Key+Shift+3 
(See the screenshot below)
Screenshot in Mac (OS X)
Screenshot in Mac (OS X)

Screenshot of a particular Area
To take the screenshot of a particular area, then you can use Command+shift+4 keys pressed and released. Once released, you will get a + symbol with x and y location. Simply drag the area you want to take a screenshot and release it. Thats it!!!. See the screenshot taken using this method.

screenshot in mac using Command+shift+4

Screenshot in mac before taking a Command+shift+4

Also, there are other methods like storing the image to a clipboard and later can be used inside the document processing applications.  Also there is a provision for storing the screenshot files in an user specified location rather than on the Desktop.

If you want to record your screen, Mac OS X has the method using Quick Time player. There may not be any need for desktop recording application, the quick time player will do that. But if you need a complete customization pack, then you may think of any such app.

Pradeep Kumar TS

How to open Ports in CentOS

CentOS is the most preferred alternative OS for RHEL. Those who cannot afford to purchase the support license of RHEL, they can use CentOS that comes with almost similar to RHEL.

This post tells you about the usage of CentOS when web servers are installed and accessed from remote machines.

CentOS is a Server based OS and most of the ports are closed by default and you need to open it for access from outside (remote).
For ex. if wordpress is installed in CentOS with a hostname  which is very well accessed within the server. When the same is tried from outside like (, then it will not get accessed.
The problem is the closure of ports in CentOS. So you need to open it and save it to iptables, here are the commands that will help you to do that.


Port number : 80 is used here

$prompt] ifconfig (find out which interface uses the assigned ip, eth1, eth0, etc)
$prompt] iptables --line -vnL
(See which line the input has to be accepted and in my case it is 6) and give the following command
$prompt] iptables -I INPUT 6 -i eth1 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
$prompt] service iptables save (Save and restart the IP Tables)
$prompt] service iptables restart

Thats all!!!! I solved this problem, when I installed MOODLE in my Blade server with Cent OS installed.

Pradeep Kumar TS