Ten Amazon Shopping Tips and Tricks You Must Know

Ten Amazon Shopping Tips And Tricks
“There are two kinds of companies: Those that work to try to charge more and those that work to charge less. We will be the second”- Jeff Bezos, founder and CEO of Amazon

Is your favorite lipstick out of stock? Is a particular item not available for sale in your country? 
Nothing to fear as Amazon practically has you covered. The company’s vast inventory makes it possible for it to be a goldmine for anything and everything. If you cannot find a particular item in your local retail store, chances are Amazon has it in stock making online shopping the perfect alternative for shoppers who prefer the convenience as well as the accessibility. Despite its popularity, there are many tips, tricks and a handful of shopping hacks that even the most seasoned shoppers are unaware of. Though Amazon may be a jungle, albeit in a metaphorical sense, some areas of the website are still vastly unexplored, and this article will assist you in navigating these uncharted paths by providing some tips and tricks. 

1) Prime Benefits 

If you routinely shop at Amazon, then you should sign up for Amazon Prime, which provides a free two-day shipping to the contiguous U.S. As shipping can get notoriously exorbitant, this can sweeten the deal for you and make your shopping endeavors hassle-free and much more affordable. Apart from the free shipping, you get access to more than a million songs for free via Prime Music, more than five hundred thousand e-books in the Kindle Owner’s Lending Library, more than forty thousand videos and TV shows and half-hour head starts on select lightning deals. 

2) Do not pay for shipping 

If you are not a prime member, having your purchased items shipped for free is still possible. Do this by ordering $35 or more of eligible items. 

3) Make a Wish 

Amazon’s wish list functions like a bridal registry for just about anyone and functions roughly the same way. It allows users to select whatever items they want and desire to receive on any special occasions. 

4) Personal Amazon Shoppers 

Sometimes, we just do not have to scour Amazon’s websites for hours just to find the best deals. This is what sites like Jungle Deals and Steals, Online Price Alerts and The Tracktor are for. They do the dirty work for us and find services such as deal alerts, notable price drops and price tracking depending on the site. 

5) Pay the lowest price 

Suppose you are ready to check out your order, but are unsure if you are getting the best price. If this is the case, use the PriceJump tool at Savings.com. Simple paste the Amazon URL and the tool will compare the cost with the price tags at other online merchants. 

6) Discounts for individuals with tots

One laudable feature Amazon has is Amazon Mom, a membership with advantageous perks for people with kids. This membership gives members twenty percent off diapers, a fifteen percent discount for completing a baby registry and discounts and deals from time to time. 

7) Discounts for students 

Students are not left out either and as Amazon offers a membership catering to students’ needs which is free for six months. A caveat, though, after six months the student will automatically be enrolled in Prime. 

8) Do not pay retail 

Amazon has its own coupons or similarly, if you do not want to pay the retail price, you can simply type “Amazon” into the search boxes of sites such as Savings.com, RetailMeNot, and FatWallet.com. These websites offer you percent-off, free shipping, and free-gift-with-purchase codes. 

9) Money back guarantee 

If you bought an item from Amazon, which goes on sale within a week from your date of purchase, you could get the difference refunded. However, if you are just feeling buyer’s remorse, you can utilize Amazon’s generous return policy. Consider that this does not cover every single item (The site indicates many can be returned not all). 

10) Gold Box Deals offer discounts 

These include heavily discounted deals all over the site plus lightning sales that expire within an hour or two. One caveat: It can get rather addicting to checking out this part of Amazon though so check at your own risk.

Author Bio: 

Abbeygail is a techie woman and wants to be always updated with the growing technology today. She is also freelance writer and blogger for MyOptimind, a company in the Philippines that develops mobile app, SEO and web design company Cebu. Aside from being techie and a blogger, she also loves to travel in different places especially in her country.

REVEALED : ANDROID N (Nougat) Latest Feature Review

Latest android N review


Android Nougat discharge date 


Instead of hold up until Google I/O 2016, Google chose to amaze all of us by discharging the main Android N designer review on March 9, two entire months sooner than anticipated. The Android N sneak peak went live for the Nexus 6P, Nexus 5X, Nexus 6, Nexus 9 (Wi-Fi and LTE), Nexus Player and Pixel C on the Android Developers site. The main beta discharge hopeful showed up amid Google I/O on May 18, 2016.

The last Android 7.0 Nougat discharge date has been affirmed for Q3, 2016, giving Google until September 30 to follow through on its course of events. This implies the Nexus 6P (2016) and Nexus 5X (2016) – or whatever they will be called for the current year – will come somewhat sooner than anticipated as well, as the new form of Android is constantly displayed close by new Nexus gadgets.

The Nexus 4 was declared on October 29, the Nexus 5 on October 31, the Nexus 6 on October 15, the Nexus 5X and 6P on September 29. So we may even see the current year's Nexuses prior in September instead of the end of the month if the logically prior declaration dates are anything to pass by.

The last Android 7.0 discharge will be restricted to Nexus gadgets at first and advance toward other producer gadgets and bearer systems over the accompanying six months or somewhere in the vicinity. You can download the Android N review underneath and streak it on a perfect gadget at this moment however make sure to counsel the rundown of known issues first. Google is endeavoring to adhere to a month to month upgrade plan for the Android Nougat sneak peaks.

Android N will be Android 7.0 


android N will be android 7
We've beforehand said how every one of the checks in the screenshots at I/O were set to 7:00 – Google's typical method for letting us know what the following Android variant number will be. All things considered, we've now essentially had Android 7.0 affirmed: on the off chance that you turn on Demo Mode in the Android N review 4 you'll see that the time is set to 7:00 also.

As of late utilized emoji expelled from Google Keyboard

This isn't precisely noteworthy news, yet as you likely acknowledge, we're currently at the cleaning and adjusting phase of Android N, so the progressions we see are going to get less provocative the nearer we get the chance to go time. In Dev Preview 3, as of late utilized emoji would show up as a part of the recommended word field of the image tab in the Google Keyboard. In Dev Preview 4 you'll need to empower that choice in the console settings: the default express no more shows emoji.

Dull Theme gone once more, Night Mode remains 


We have no clue what's happening with Google and Android's Dark Theme. It initially showed up back in the Android M designer reviews yet never made it to Marshmallow legitimate. It then reemerged in Android N with different noteworthy headways yet is presently gone, once more.

Google has said that Night Mode and the Dark Theme are "far-fetched" to make it into the last Android 7.0 discharge, yet that it hasn't discounted them completely. Clearly, neither one of the features met Google's execution benchmarks. In Dev Preview 3, Dark Theme is gone, however Night Mode stays in the Quick Settings.

Google giveth and Google taketh away. Generally as we lose the adored Dark Theme for Android overall, we pick up topics for the Google Keyboard in Android N. Rendition 5.1 of Google Keyboard includes a cluster of beautiful theming choices, including the capacity to set your own particular picture foundation.

More changes to multitasking 


Multitasking in Android N is a passionate rollercoaster of extents likened to the Dark Theme. The main Dev Preview had a cluster of new multitasking choices (see underneath), some of which were evacuated in Dev Preview 2. In Dev Preview 3 things change once more. Application exchanging between your two latest applications by twofold tapping the multitasking catch remains (thank sky), however the quantity of applications will be diminished to seven.

The "Unmistakable All" catch at the highest point of the card stack has strangely exchanged sides: from left in Preview 2 to right in sneak peak 3. Dispatching multi-window mode in the recents rundown is currently enacted by long-squeezing an application and dragging it up as opposed to left in Dev Preview 2. You can at present empower a swipe-up signal on the recents catch to dispatch multi-window mode in the System UI Tuner settings.

Other new stuff in Android N (Dev Preview 3)

As said over, the Android N Developer Preview 3 is more about calibrating likely Android 7.0 components and evacuating those unrealistic to make the cut. Unfortunately for enthusiasts of the Dark Theme and Night Mode, Launcher Shortcuts, progressed multitasking easy routes, those offbeat new organizer symbols or the screen catch in video mode, it would appear that these elements may not make the cut.

Multi-window mode 


The primary authority Android N highlight to be affirmed was multi-window mode, with the affirmation coming, indefinitely enough, by means of a Reddit AMA with the Pixel C group a couple of months back. Amid the exchange, Andrew Bowers affirmed that "split screen is in progress" and with the arrival of Android N designer review 1, we can now see precisely how Android 7.0 split screen mode will look.

Good applications (engineers should include support for split screen mode separately) can be opened up one next to the other in Android N and resized with a portable slider. You can move and customize content between split screen windows and go full screen by dragging the slider the distance to the edge.

Engineers will have the capacity to set a base size for their application windows yet you'll have a fundamentally the same as multitasking background to what you as of now find on numerous OEM gadgets. There's additionally another photo in-picture mode for Android TV that works simply like minimized video in YouTube.

Upgraded Doze Mode 


As anticipated, the loved and admired Marshmallow highlight, Doze Mode, has likewise been enhanced in Android N. Rest now highlights a two-level framework. The primary works at whatever point the screen has been off for some time, whether your telephone is stationary or not. This implies you can now appreciate the advantages of Doze Mode at whatever time your telephone is not being utilized, notwithstanding when it is in your pocket or knapsack. The other layer of Doze Mode fills in as some time recently, yet with some more upgrades. At the point when your telephone is lying still, it will enter a more profound hibernation mode, conceding system and other action until broadly divided out "support" windows before slipping back to rest.

One element that is not formally part of the Android N engineer review at this moment is freestyle window mode. As an informal part of an engineer review for an Android form that won't arrive formally until six months from now, it is a long way from prepared for prime time, yet it works basically as you'd anticipate that it will. You can dispatch different applications at the one time, resize them and move them around the screen anyway you like. Move and customize content is likewise bolstered in freestyle window mode.

Update: study the RhonzNET review of the Android N -

Try to Focus on SEO in Keyword "Everest Base Camp Trek" Seems A Bit Challenging in Nepal

Everest Base Camp Trek Keyworda

"Everest Base Camp Trek" is a keyword that every travel and trekking agency of Nepal wants to focus. However, it seems little bit challenging to SEO experts to focus in keyword "Everest Base Camp Trek" in Nepal. By the way, SEO has been becoming more difficult day by day. In earlier, SEO is too easier. As you made lots of backlinks, then your site used to show in very first page in several keywords. But now, time has changed; there are trillions more information in the internet. So Google always considers to show best information to the searchers. And focusing keyword is a very most important factor of SEO.

Being a SEO counselor, I have analyzed several keywords that a trekking and tour agency of Nepal wants to focus in internet. However, they even do not know SEO is consistent work. It could not be done within a week or a single month. In fact, it may take 3 - 4 months or number of months too and that only depends on keyword status, keyword competition, and also suggested bid on a particular keyword. But I can assure you that your site status goes high within first month as you start to do SEO.

In average, 12 thousand people search Everest Base Camp each month. Actually, it is not the huge amount of query, whereas there are 1500 - 25000 approx. sites which have written about Everest Base Camp focusing on the keyword "Everest Base Camp Trek". So those SEO experts, who are working to bring their site in between 1 - 10 page of Google while searching "Everest Base Camp Trek". Then they must perceive a thing in his mind is that competition is too hard. Therefore, they must provide a good and authenticate information about Everest Base Camp along with updated information, such as recent events, news etc. In addition, you do have to list out some extra information instead of writing in paragraph. Just apply an exam writing format to write article about Everest Base Camp, such as use 3 - 4 paragraphs of good worth amount of words, use listing information in points, show some quotations using quotation tag etc.

Eventually, let it be known that Everest Base Camp Trek keyword is little bit challenging to bring in search engines front pages. However, I am not saying impossible. Just do handwork and uplift your business.

Good Luck.

Read also: Top 10 Seo Expert Company in Nepal 

How to add Latest Facebook Comment Box in Blogspots or Blogger

Facebook has provided many plugins for websites and blogs. Recently the developers of Facebook have released the plugins “Facebook Comment Box”. This is awesome plugin of the Facebook. Using this Facebook comment box your blogger and websites user or viewers can comment on your posts and those comments will be automatically shared in their Facebook Comment Wall.

Facebook comment box makes your visitors catch you easily, so this can be very important for those people who want directly interact with the admin and other visitors. I know there are various people who want to know the Facebook comment box on their blogger blog, Wordpress blog and many other site. So this tutorial can be the best solution for them. So now we will suggest you how to add simple comment box of Facebook in the blogger blog. You should that everything have its merits and demerits. Likewise, this Facebook comment box also its some advantages and some disadvantages.

First of all, here we are discuss about the advantages of the Facebook comment box.
We all know that Facebook is the most popular social media of the world. They always introduce new features to serve the people and to catch the visitors more on the Facebook. So Facebook comment box is one of their popular feature.
when some people like and reply to their comment. notification is appeared to the user. And it also provides multiple commenting features.

The main disadvantage of Facebook comment box in blogger is that Google spider never crawl Facebook comment, so these comment can not be useful in the view of optimization.

You just find here two methods to put this comment box in your blogger blog. Both are very useful but in some of older blog's templates Method 1 might not work. So I recommend you to use the methods which works in your blog.
This are one of the most using techniques to making more visitors on your blogs and sites.

1. Create a New app

New app id

It is the beginning thing that you should do which you can do easily by Facebook developer. First of all you should login into your Facebook then click on Facebook developers. After that click on Create New App
and their appears a pop of form. Fill that form. Then fill that Captcha. Then copy the app id into your notepad, this is needed in further steps.
facebook apps

2. Now lets install the Facebook comment in blogger blog

It is necessary to login into your Facebook dashboard. Then go to template tab and click on edit html. After that find the following code.
<html......> This code is in the first row of every blogger, so you can find it easily.

Then, just paste the following xmlns:og='http://ogp.me/ns#' code just after the highlighted code which is shown in above. When you add this code the html structure is look like
<html xmlns:og='http://ogp.me/ns#' ...... xmlns:expr='http://www.google.com/2005/gml/expr'>
Now find the <body> tag and paste the given code just after that <body>

<div id='fb-root'/> 
<script> 
    window.fbAsyncInit = function() { 
    FB.init({ 
      appId  : &#39;AppId&#39;, 
      status : true, // check login status 
        cookie : true, // enable cookies to allow the server to access the   session 
      xfbml  : true  // parse XFBML 
    }); 
  };
    (function() { 
    var e = document.createElement(&#39;script&#39;); 
      e.src = document.location.protocol +   &#39;//connect.facebook.net/en_US/all.js&#39;; 
    e.async = true; 
      document.getElementById(&#39;fb-root&#39;).appendChild(e); 
    }()); 
</script>

The one thing is that you just replace or add your AppId below AppId.  You put your blog name in All Blog Solution  and your facebook page url in http://www.facebook.com/allblogsolution.
Now there is needed to add meta tags. Just find the </head> and paste the following code replacing your app id
<meta expr:content='data:blog.pageTitle' property='og:title'/> 
<meta expr:content='data:blog.url' property='og:url'/> 
<meta content='AppId ' property='fb:app_id'/> 
<meta content='All Blog Solution' property='og:site_name'/> 
<meta content='http://www.facebook.com/allblogsolution' property='fb:admins'/> 
<meta content='article' property='og:type'/>

3. Comment box in blogger blog.

At last you should put comment box structure in the blog.
Go and just find this code <div class='post-footer-line post-footer-line-1'> and paste the following code just below the above code or anywhere you want to show the Facebook comment box.

<b:if cond='data:blog.pageType == &quot;item&quot;'>
  <div style='padding:2px 3px 2px 3px; margin:2px 3px 2px 3px;'><script src='http://connect.facebook.net/en_US/all.js#xfbml=1'/>
    <div>
      <fb:comments  colorscheme='light' expr:href='data:post.url' expr:title='data:post.title' expr:xid='data:post.id' width='100%'/>
    </div>
  </div>
</b:if>
<div style="position:fixed; bottom:0px; left:0px; color:#898989; font-size:12px;"><a href="http;//techydesk.blogspot.com">Get Widget</a></div> 

Now you have successfully add your Facebook comment box.

Note: Replace http://allblogsolution.blogspot.com by your blogurl. If you want to change the width of comment, simply change the width. Thanks you did.

Watch and follow the below video

Top 10 SEO Companies in Nepal

Top SEO companies in Nepal

SEO is the best way to increase organic visitors in a site. Every business organization wants to grow their business in any manner. Nowadays, many business organizations are moving on online business leaving their traditional marketing approach. Developed countries have already been rapidly shifting their all business in online and they are successful in online business. So online business marketing has been challenging in current days. Therefore, Search Engine Optimization is being popular day and day. In order to provide SEO classes, SEO consultancy has been growing rapidly not only in developed countries but also in under-developed and developing countries as they are also shifting their businesses in online.

Although Nepal is developing country, there is also very much scope of Search Engine Optimization. In Nepal, most of the SEO projects are offered by Trekking and Tours Companies because trekking and tours field is the only best way that can grow the GDP (Gross Domestic Product) of Nepal.

To those who wants best SEO company in Nepal, here we have made a list of top 10 companies

1) Weblink Nepal

Address: Bagbazaar Kathmandu
Email: info@weblinknepal.com
Website: Weblink[dot]com

2) SEO Service Nepal


Address: Maharajgunj, Kathmandu
Website: seoservicenepal[dot]com

3) IamIT P. Ltd

Address: Thamel,Kathmandu
Email: info@iamit.com.np
Website: iamit[dot]com[dot]np

4) SEO Services Nepal


Address: Jadibuti, Koteshwar, Nepal
Email: info@seoservicesnepal[dot]com
Website: seoservicesnepal[dot]com

5) Website Design Nepal

Address: Naradevi, Kathmandu
Email: info@webdesigninnepal.com
Website: webdesigninnepal[dot]com

6) Mero Server

Address: Birtamod, Jhapa
Email: mail@meroserver.com
Website: meroserver[dot]com

7) SEO Nepal

Address: Lazimpat, Kathmandu
Email: seo@seonepal.com
Website: seonepal[dot]com

8) SEO Training Nepal

Address: Old Buspark, Kathmandu
Email: seo@webcreationnepal.com
Website: seotrainingnepal[dot]com

9) IT Training Nepal

Address: Putalisadak, Kathmandu
Email: info@ittrainingnepal.com
Website: ittrainingnepal[dot]com

10) Nep Sol

Address: Tinkune, Koteshwar, Kathmandu
Email: info@nepsolweb.com
Website: nepsolweb[dot]com


Note: We made a copy of list of these websites by the people reactions about them. However, we do not give any assurance about their working abilities and loyalties.

How to Earn From Microworkers

Microworkers of the world
Microworkers is for the micro jobs. It means you can not earn more money by completing one task. But when you complete your job correctly, you will sure collect your money. Microworkers is very trustful platform, it never cheats you. There you can see no of tasks in the microworker sites, then you should complete these task. In each task has its particular money. Many task has less than $ 1 but you can do multiple task. It is very easy to complete these task but you should have patient do to them. If you are searching for long time to work and get money, microworker can be your best platform.
Microworkers provide mostly simple and click paste jobs, sign up and sign in, writing jobs, commenting, article writing, guest posting, photo liking, click and giving the impression to the sites etc.

How to get money through Microworkers.com?


You should just sign up the microworkers account. Then just log in into the dashboard. Then their you can see the microworkers tab bar tabs: Jobs, Hg jobs, Task I finished, My campaign, deposit, withdraw, account.
By clicking jobs tab you can see the varius jobs. There only appears the jobs which are available for you because microworkers reviews all your jobs. If you do better jobs in the initial phase, then microworkers offer better and more jobs to you otherwise you are penalize and there appears few and less money jobs for you. So be careful while doing the jobs. But in the initil time you are offered average jobs. Here I am going to show you the step by step process to complete and task offered by microworkers:-

Step 1: After login into your dashboard click on the Jobs tab. There you will see many jobs in category form like sign up job, click,search, bookmark, google, youtube,facebook etc.

Step 2: Choose one category like in the figure here I choose all jobs category.

Microworkers jobs

Step 3: Then choose one task among them. Here I choose Amazing work:sign up task.

Step 4: Now another link will open and there you will find the publisher's expected work from the workders.

Step 5: Read carefully the given expected info. and then do just as they said.

expected jobs from workers

Step 6: After doing this you should provide the proof of your jobs done as they say.

Step 7: Now click on confirm button.

You did it successfully but you should know where the earned money will appear.
After your confirm your job done, then your done job will appear in the task i finished page. Just click there and now there you can see your done job but in the minus sign. The sign will be green right after reviewing and accepting by the publisher, then the determined money will appear in your account.

You also should have a questions when can I get the money. You can get that money when you make $10. When your account has 10 dollars, then microworkers will sent you a address pin in your address and you should do as they advice. 

Difference between Pipe and Fifo

Difference between Pipe and Fifo
Pipe and Fifo both are IPC (Inter Process Communication) object.

Pipe (IPC Object)

  • Pipe does not have any name unlike Fifo.
  • Pipe is a structure of data which is contained into the memory. It is removed when existing process terminates.
  • Basically, Pipe is used to communicate between 2 or more related processes.
  • If Pipe is already in opened state, then it does not need to be opened.
  • Pipe provides simplex data flow
  • eg: pipe(int fd[2])

Fifo (IPC Object)

  • Fifo is also an IPC object, but it has its name.
  • Unlike Pipe, it is a structure of file which is created in disc.
  • It is also used for communication but only between unrelated processes.
  • It should be opened every time when it needs to write and read.
  • Fifo provides half duplex data flow.
  • eg: mkfifo(const char * path_name, mode_t mode)

How I removed Snap.do Browser Hijacker Virus Completely From My Computer

How many of you guys are familiar with snap.do browser hijacker virus? I think many of you who mostly searches software crackers and patchers in internet have been troubled by this virus. Snap.do hijacks your computer browser and redirects you to the random url. In fact, I was also got this opportunity to be familiar with this hijacker virus as one of my friends' laptop infected by this virus. I tried constantly 3 days, then I got its solution. I did everything as possible as I can. I also searched solution of this hijacker in internet but did not get the actual working solution. Some websites say buy hijackers removal software and some's solution did not work. However, I did not give up, I tried until it was fixed, then I got success to remove it completely from the system. Lets follow the step by step solution to know how I removed this virus.
Snap.do browser hijacker virus supposed figure

Step 01: Often, you can not get snap.do virus in control panel installed software lists. However, you can not leave this. So you should visit control panel and uninstall software whether there is snap.do virus software. If it is there, then just uninstall it.

Step 02: In order to remove snap.do from registry, you should enter into registry. You can type regedit in the search bar of your computer and enter into registry where you will see different files. Do not touch any other files, just type snap.do or snap and search it and delete if you find these files. Often these are located in the HKEY_CURRENT_USER>>microsoft windows.

Step 03: Use any of the virus cleaner software. Mostly I recommended to use premium software because premium are more reliable. Do not use those software whose development corporation have not been specified. You can use Hitman Pro; though it is a premium software, you can use it in trial period. It helps to clean unnecessary files and doubted viruses.

Step 04: Go to your browser's extension and delete the snap.do extension if you see it there.

Step 05: At last, you have to find ronzap file in your computer. To do so, you have to go to run application of your computer and search for ronzap file. Then remove it. This is most important step since if you follow all above step but forget to delete ronzap file from your computer, even though you can not get rid of from this snap.do hijacker virus.

Hope, you find it useful.

Note: I have shared all above steps from my own experience. We do not become responsible if you get any harm using these steps. 

Inter Process Communication Objects - pipe()

Inter Process Communication Objects - pipe()

  • In unix system, pipe is known as an inter process communication mechanism.
  • A process can write data to pipe, and that data can be read by another process.
  • In pipe IPC, the data is handled in fifo i.e first in first out order.
  • Pipe does not have any name, it is only created for one use and both ends must be inherited from the single process which created the pipe.
  • Since it is a IPC object, it is used to communicate between two process i.e parent and child.
  • Pipe is created using pipe function (pipe()). Pipe also creates description pair which can be denoted as fd[0], fd[1]. Primarily fd[0] for reading and fd[1] for writing.
  • As pipe sets up, the data can be passed using read and write functions.

Elementary System Calls - Wait() and Waitpid()

Elementary System Calls - Wait() and Waitpid()
Wait function suspends the execution of the calling process until one of its children terminates.

Waitpid suspends execution of the calling process until a child specified by pid argument has changed state.

Wait():

  • Wait() continues to block the caller until a child process terminates.
  • If there are more than one child running, wait() returns the first time one of the parent's offspring exists
  • It doesn't support job control.

Waitpid():

  • It can be either blocking or non-blocking:
if 0, blocking
if WNOHANG, non-blocking
It is flexible
It waits for child process if pid is -1
It waits for child of greater process id if pid>0
It waits for any child whose process group ID equals that of the calling process if pid equals to 0.
It waits for any child whose process group ID equals that absolute value of pid. 
  • It supports job control. 

exec() family calls - Network Programming

exec() family calls - Network Programming
A child process (process created using fork()) can execute any other program using exec(). There are 6 exec() family calls in network programming.

The process is executed in memory by new program file from disk, and the process is replaced as well.

In here, the new program only executes; there is not being created new process. Therefore, no change occurs in process ID.

Six exec() family calls:

1) execl: 


  • execl is the first member of exec() family.
  • It can take several arguments. It always takes full pathname as the first argument.
  • It accepts a null pointer which marks the end of arguments in execl.


Lets see a simple example of execl. Lets suppose we have newscript.sh

#!/bin/ksh
echo "Hello Execl"

Now lets see a simple program which is written in C language to understand the actual use of execl.

void main()
{
      execl("/home/users/newscript.sh","newscript.sh",(char *)0);
      exit(0);
      getch();
}

2) execv: 


execl and execv works same, however, there is a minor difference between them and i.e arguments for the script in the array can be passed in execv, but execl passes them individually.

3) execlp: 

execl and execv are same but in execlp we only pass the name of script unlike execl on which full path is passed.

4) execvp:

exev and excvp are same but excvp takes the full path of script and only replaces the individual arguments given in the execlp. 

5) execle

Unlike other methods, it takes extra environmental argument variable. 

6) execve:

It works same as execle does, however unlike the execle, it takes arguments for the script in an array.


Synopsis of different exec() family calls:

int execl(const char *pathname, const char *argument(),......., const char *argmentName, (char *)0);
int execle(const char *pathname, const char *argument(),......., const char *argmentName, (char *)0, char * const envp[]);
int execlp(const char *filename, const char *argument(),......., const char *argmentName, (char *)0);
int execv(const char *pathname, char * const argumentValue[]);
int execve(const char *pathname, char * const argumentValue[], char * const envp[]);
int execvp(const char *filename, char *argumentValue[]);


Elementary Operating System Call - Fork()

Elementary Operating System Call - Fork()

What is system call ?

Karnel is the heart of Computer System. In computer system, a request has to be made by operating system to the Karnel in order to get the service, and it is only done in programmatic way, which is known as system call.

Program is a collection of instructions that is made to complete a particular task. And a process is a particular program which is currently in running status.

Thread includes in process i.e process has some properties of thread - a single sequence stream within process is called thread.


Fork() 



  • In UNIX system, we use Fork() to create duplicate of a process by creating address space for duplicate one.
  • The process from which fork method is called, known as parent process. And child process is the new created process. Child and Parent, both processes return from the system call and execute the next instruction. 
  • Child process has all the features and ability of parent process i.e all memory segments of parent process are consumed by child process also. Parent and Child both processes execute independently whereas there is same code for both processes.
  • Parent and Child both process have different process IDs. They are executed at different memory address. 
  • As fork method executes, it returns twice - 0 and process ID to parent process if fork is successfully executed and it returns -1 if it is failed.
Synopsis
#include<unistd.h>
pid_t fork(void);