While working on the bash shell we sometimes requires to use some commands frequently. Instead of typing and recalling previous commands you configure your bash history setting to run your commandline operations smoothly.

Following settings will help you :

*) Don’t save duplicates :

HISTCONTROL=ignoreboth
Using this command we ignore any lines matching the previous history and are not saved. Other options for HISTCONTROL: ignorespace, lines which begin with a space character are not saved in the history list; erasedups causes all previous lines matching the current line to be removed from the history list before that line is saved.

*) Size of the history:

HISTSIZE=500
Using this we can set the number of commands to remember in the command history. The default value is 500.

*) Others:

HISTFILE:
The name of the file in which command history is saved.
Generally it is at ~/.bash_history.

HISTIGNORE:
A colon-separated list of patterns used to decide which command lines should be saved on the history list.

We set these options either by export them in your environment in your personal bash configuration file (~/.bashrc) or in the global bash configuration file (/etc/bash.bashrc). The name of the configuration files can depend from your Linux distribution and bash version.
To get activated these setting you need to restart your bash session.
To verify your configuration setting type env at the command prompt.

Tip : “ The most efficent way to search your history is to hit Ctrl R and type the start of the command. It will autocomplete as soon as there’s a match to a history entry, then you just hit enter ”

Normally we press CTRL+ALT+DEL for rebooting our system, but sometimes you feel that such concurrent key press should not reboot your system. suppose your system is of production type systems which is to be prevented from such keystrokes just for security reason as someone might make some mistake and reboot the system.

For a linux systems using this shortcut you don’t need to logged in
(no user/password needed - but only console access) to reboot the system.
If you need to protect yourself from unauthorise reboot you have to disable
such shortcut.

How to disable this shortcut :

On linux machine the action taken for CTRL-ALT-DEL is defined in /etc/inittab
on RedHat based systems the file under /etc/inittab will look like: ca::ctrlaltdel:/sbin/shutdown -t3 -r now

If we want to disable this action we only have to change this line.
We can delete it, comment it, or even replace it with something like: ca:12345:ctrlaltdel:/bin/echo “CTRL-ALT-DEL is disabled”

After making any changes to the inittab file, you will have to tell init to reload
it, in order to activate the changes. To do that, simply run as root : init q

Now try pressing CTRL-ALT-DEL you will find your system has no effect for such shortcut.

There are different type of robots for different function in Search Engine, some robots index the HTML Titles, or the first few paragraphs, or index all words, with giving more weight on HTML constructs, etc. Some parse the META tag, or a hidden tags, while some decide to index or not that based on the attribute of your site. However if an indexing robot know your site document it may decide to parse it by recognizing words and phrases in text, and insert information into its database, that depends on the robot as each one robot uses different strategy. However all robots are going to read your robot.txt file if present.

The popularity of a website is extremely important while all search engines can find out how many links are going to and from your page. If you have good number of outgoing and inbound link there are more chances that the indexing robots can consider for deep crawling.

To block a particular website on your computer follow the following steps:

Step 1:

Go to

C:\WINDOWS\system32\drivers\etc

Step 2:

Open a “host” file in notepad. At the bottom of the line, you can see as follows
127.0.0.1 localhost

Add the following line at the end

Ex: 127.0.0.1 www.abcxyz.com localhost

The above code is written to block www.abcxyz.com website on my pc.

As a professional webdesigner you should always make your visitor to move smoothly through your site. They should be aware of where they are and where they can go.Your website should be flexible. You can achieve this by implementing proper navigation scheme for yor site.
Your navigation can be considered as a road map for your site. If your site is poorly built for navigation then there are much chances of loosing visitor, if they get lost in your site.
Tips for Web site navigation :
Title: All navigation links should have a short and descriptive title making it easy for the user to understand where it links.

Importance : The primary navigation should not have more than 6-7 links. Keep only the most important links in the primary navigation and leave the rest for the secondary navigation.

Uniqueness : Always try to make your primary navigation links more unique by using some graphics or different links style.

Alternative link : If using graphics or javascript links, a text alternative should be available. Some people might have the graphics turned off or javascript disabled when browsing the Internet. In such cases an alternate option should be available.You can have a text menu and the bottom of the page could be included.

Keep it minimum: On every page there should be a reasonable number of links. Pages with 20-30 links are harder to use than pages with 10 links. Visitors don’t have the time to click on all of them to see if they are interested in the information secluded behind them. The best approach is group similar links in categories and let people discover them click upon click.

Today’s web has become more interactive then ever, more and more sites are coming up with dynamic structure providing visitors to add/modify contents. This can be achieved by using some dynamic script like PHP or JavaScript which help to set up an interactive sessions for a website.

Pages having such scripts gets dynamic url may be something like http://www.somesites.com/forums/thread.php?threadid=12345&sort=date
Such dynamic url have some special characters in them as ?,&,= making their nature dynamic.

Whenever searchspider founds such offending character in url it makes it difficult to crawl/recognize such links resulting it ignores the url itself.As far as SEO is concern it is harmful that your links are not get crawled thus your page content, this affect your SERP and your ranking.

So what is the solution ?

For making such dynamic url to get crawl you can go for Mod Rewrite rule or else Isapi Rewrite which converts your dynamic url into static one.
If you website is hosted on a Unix server, you can may be able to use a Mod Rewrite to change dynamic urls to static and if you are on Windows servers, you would need to change using Isapi Rewrite.

Once you have static versions of these urls then remember to do is to change all of your links in your website to the static urls in order to avoid penalties by search engines due to having duplicate urls.You can also add your dynamic urls to your Robots.txt to keep away the search engines from spidering these duplicate urls.

Processor speeds have increased dramatically in recent years. As a result, the heat given out by processors has also increased also the noise associated with equipment, such as fans, used to keep them running at a safe temperature. To overcome this engineers have suggested a method “ Water Cooling “.

Water cooling is a method used to lower the temperatures of computer processors or graphic cards which may get heat up easily. In this method water is used as a cooling medium instead of air. You know water can conduct heat about 30 times faster than air can, a water cooling system allows the processor to run at higher speeds while drastically reducing system noise.

How it works :

A pump circulates the water through a water block (a device similar to a heat sink) attached to the processor; there, heat from the processor transfers to the water. The heated water continues on to a radiator at the back of the computer case and is replaced with cool water. The heat from the water in the radiator dissipates into the air surrounding the computer. When the water has cooled to the lower temperature, it is cycled through the system again.

Issues :

Water cooling brings its own issues :
*) Additional plumbing is often required for flowing and pumping water over devices.

*) As water is being used as a medium their can be problem of rust or leakage in the channel which can be hazardous.

*) The combination of electronic systems and water also complicates disaster recovery planning.

*) Need to take more precaution while handling and transportation.

Despite the inherent challenges, many industry experts predict that water cooling is the inescapable future in hardware industry.

You can have video documentation for implementation of this new cooling tech at : http://www.youtube.com/watch?v=ceuKDF8CLm4

Everyone today knows what is Google Sandbox as it was put into action back in March 2004. All the new websites are put into an initial probation status by the sandbox filter. New websites may get into Google’s SERP’s relatively fast and may also carry out well for a couple of weeks. The filter when applied to the new website it is referred to as being put in the ‘sandbox’. The new websites will still be shown on the results page but actually won’t rank good regardless of how original and optimized content is there and the number of quality inbound links your site has. The job of the filter is to hold back new websites from having immediate success in the SERP’s. Don’t be surprised if your ranks are decent in all the major engines but the rankings in Google are not up at all, you must have probably been sandboxed.

Webmasters all over don’t like the Google Sandbox but an effective webmaster will always make a website taking sandbox as an opportunity that even Google cannot reject.
Guys to help your site break-away from the sandbox you may apply these steps which are definitely going to work for your website:

a) The layout of your website should be changed.

b) New and informative content be added to the site.

c) Submit the articles with the name of your website attached to boost the link popularity.

Google ranks all the websites in the same way like in the past keeping the basic elements of ranking same but it will continue to change the process of evaluating inbound links and quality of the content. There are some people who say that it takes 4 to 12 months while some say it takes only a few weeks to come out of the sandbox but be sure if you don’t do anything your website may not be released from the sandbox.
Always remember that the sandbox is there to only reduce SE spams and not to hold people back from their success. Google favors websites which are offering good, relevant and quality content and it still relies on the natural voting system to establish the PR.

As far as hosting is concern we have multiple choices such as shared hosting, dedicated hosting, VPS Hosting. Depending on our need and budget we opt the one. Each type has its own importance.
Although hosting your web sites on your own dedicated server may seem a little expensive in comparison to shared web hosting but the cost may be covered through the benefit we get.

*) Shared web hosting, no matter how well managed, cannot be always 100% reliable and stable whereas if you have dedicated server you can manage to avoid most of the variables affecting the reliability and stability of a server.

*) On a dedicated server you will install only software and applications you want to use, while on a shared hosting server you will find a host of other software and applications installed for other users.

*) A dedicated server:reduces your dependency on the web host; and bypasses time delays and possible expenses incurred from these. Where as in shared hosting you don’t have much more rights to resolve your problems so it may take time to get settle on certain issue.

*) As compared to shared hosting in dedicated server hosting you get instant support from your host whenever required, they give you more priority.

*) Dedicated server helps you to load your site faster and there are much less chances that you site is down due to certain technical reason this will ensure your visitor won’t leave your site.

Doorway domain sites are one or two page sites and which are highly targeted to a specific search word or phrase. They links to your main site. Here a keyword-rich domain name used to achieve high search engine ranking for a particular keyword / key phrase. This sites generally links to your main site.

It is similar to a doorway page, the doorway domain serves only as a point of entry that leads search engine traffic through to the “real” content of the page.
The main purpose of doorway domain sites is to pick up extra traffic by focusing the entire site to one or maybe two search terms. If you target two search terms then ensure that these are very closely related too.

If you host all of your doorway domain sites on the same host as your main site your main would not get PR benefit as these links site would be on the same IP address and search engines don’t give any credit for such links (backlinks from same IP address).
Although this technique is not advisable as it can be considered as spamming.