With the advent of time and technology, the concept of Open Source and Working with Linux is increasing. People are moving away from propritery softwares now. And i hope many of us here must be working on Linux or Unix systems too. And while working on such systems we cannot deny the importance of working on Comman Line Interface. The power of Linux is in its Shell and and shell is the one that interprets our commands to a language computer can understand.

So i'll be explaining about some of the important Linux Commands which will be helpful for getting an idea about how they work. Linux commands can be used with [options] which is like customizing the command as per the requirement.

1. cat [options] [file-list]

This command can be use to create, Join and display files. The cat utility copies files to standard output. You can use cat to display the contents of one or more text files on the screen. Here the file-list is a list of the pathnames of one or more files that cat processes. If you do not specify an argument or if you specify a hyphen (–) in place of a filename, cat reads from standard input.

We can use cat to create short text files without using an editor like shown below.

$ cat > ... write your content here ... ... write your content here ... 

And when you want to end the file just press: CONTROL-D

Note:means you can give any filename of your choice

To displays the contents of the text file on the terminal you need to type:

$ cat 

The next example catenates three text files and redirects the output to the all file:

$ cat  1.txt 2.txt 3.txt  > all.txt

Note of Caution: If the filename already exist, the prompt won't warn you and will simply overwrite the file So use it cutiously.

2. who [options]

We need to understand that the Linux is a multiuser operating system and so there might be many users logged in. So if a system administrator wants to know about them , he needs to use the command who.

who am i The who utility displays information about users who are logged in on the local system.

$ who puneet tty1 Jul 30 06:01 amar    
tty2 Jul 30 06:02 Jyoti    tty3 Jul 30 14:56  

$ who am i 
puneet tty1 Jul 30 06:01 

3. cd [options] [directory]

Changes to another working directory. The cd builtin makes directory the working directory. Lets use the cd command to makes Puneet's home directory his working directory. To know the current working directory, we can use the command pwd( print working Direcotry) like this:

$ pwd  /home/puneet/work 

Then type

$ cd 

And then to confirm the working directory is changed type below command again

$ pwd 
/home/puneet 

So if the directory puneet is having subdiretory named work. cd command can be used to make that as working directory like this:

$ cd work 
$ pwd 
/home/puneet/work 

To go back to the parent direcotry we can use the command as:

$ cd .. 
$ pwd 
/home/puneet/ 

4. date [options] [+format]

Displays or sets the system time and date. The date utility displays the time and date known to the system. Superuser can use date to change the system clock. Use the below command to change the date without changing the year.

$ date 
08191407.30 Sat Aug 19 14:07:30 IST 2012 

We can use different format options display the date in a commonly used format. So type:

$ date '+Today is %h %d, %Y' 

Output should be:

Today is Aug 19, 2005 

5.ps [options] [process-list]

An operating system has processes and the administrator is required to know the kind of processes running and their status. So the ps command can be used to display process status. The ps utility displays status information about processes running on the local system.

$ ps 
PID   TTY   TIME       CMD 
2697 pts/0 00:00:02  bash 
3299 pts/0 00:00:00  ps   

With the –l (long) option, ps displays more information about the processes:

$ ps -l F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 000 S 500 2697 2696 0 75 0 - 639 wait4 pts/0 00:00:02 bash 000 R 500 3300 2697 0 76 0 - 744 - pts/0 00:00:00 ps 

With option u , it can be used to display more user information.

$ ps -u 
USER     PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
puneet 2697 0.0 0.5 2556 1460 pts/0 S Jul31 0:02 -bash 
puneet 3303 0.0 0.2 2476 616 pts/0 R Jul31 0:00 ps -u 

6. kill [option] PID-list

Terminates a process by PID. The kill utility terminates one or more processes by sending them signals. By default kill sends a software termination signal (signal number 15). For kill to work, the process must belong to the user executing kill, with one exception: Superuser can terminate any process. The ps utility can be used to determine the PID.

$ kill 259 

Sometime as process gets hanged so we can kill it forcefully using the command:

$ kill  -9 259 

7. nice [option] [command-line]

Nice command is used to change the priority of a command. The nice utility reports the priority of the shell or alters the priority of a command. An ordinary user can decrease the priority of a command. Only Superuser can increase the priority of a command. Negative means highest priority and positive means lowest priority. The priority ranges from -19 to +20

Below is the example of nice command which finds very large files and runs at a high priority (–15):

$ nice -n -15 find / -size +50000k 

8. chown [options]

Changes the owner of a file and/or the group the file is associated with. Only root can change the owner of a file. Only root or the owner of a file who belongs to the new group can change the group a file is associated with. The following command changes the owner of the data file in the work directory. The new owner is Aman.

$ chown aman work/data 

The following command makes puneet the owner of, and puneet's login group the group associated with, all files in the /home/aman/work directory and in all its subdirectories.

$ chown --recursive puneet: /home/aman/work 

The next command changes the ownership of the files in work direcotry of aman to puneet and the group associated with these files to pcgroup:

$ chown puneet:pcgroup /home/aman/work/* 

The final example changes the only the group association of the files in work to pcgroup without altering their ownership. The owner of the files, who is executing this command, must belong to the pcgroup group.

$ chown :pcgroup work/* 

9. cmp [options] file1 [file2 [skip1 [skip2]]]

This command is used to compares two files. The cmp utility displays the differences between two files on a byte-by-byte basis. If the files are the same, cmp is silent. If the files differ, cmp displays the byte and line number of the first difference.

The file1 and file2 are pathnames of the files that cmp compares. If file2 is omitted, cmp uses standard input instead. Using a hyphen (–) in place of file1 or file2 causes cmp to read standard input instead of that file. The skip1 and skip2 are decimal numbers indicating the number of bytes to skip in each file before beginning the comparison.

The examples use the files a and b shown below. These files have two differences. The first difference is that the word lazy in file a is replaced by lasy in file b. The second difference is more subtle: A TAB character appears just before the NEWLINE character in file b.

$ cat a I am Writing this article for boddunan. 
$ cat b I am writing this article for boddunan.TAB 

The first example uses cmp without any options to compare the two files. The cmp utility reports that the files are different and identifies the offset from the start of the files where the first difference is found:

$ cmp a b a b 
differ: char 39, line 1 

These were the basic commands you can use while working. Try them with different options.

Please do let me know in case you want to know about more commands. I'll be happy to help. Hope you enjoy reading it.

Well, first of all i would like to thank my friends here in boddunan who encouraged me to write an article on Careers Options after Computer Science Engineering. Being myself a Computer Engineer i feel good to write about it. So lets start right away.

Prolouge:

Very few people choose Engineering as their own choice. Other choose it becasue of family pressure because of society and the environment we live in. Obviously when people talk about the hefty pay packages they are getting then we tend to incline towards it. And Engineering or i would say with the advent of Technology: Computer Sceince Engineering is indeed a good option for a Career.

So you have two options after 10th:

1. Go for 11th-12th in Non Medical Stream and then choose for 4 Year Engineering Course

2. Go for JET after 10th, which is a Diploma Course in Engineering.

I won't be talking about JET much but it is good option for those who can't afford to pay high fees of Engineering Degree and can find a decent job after their diploma although not as high profile as a degree but decent enough to start early phase of Earning.

Back to the Point:

Now after you are done with your Engineering Degree, what kind of options do you have to go for. What you will be taught in college will be nothing much close to what you will learn in the Organization and hence these days companies are giving few months of training sessions to mould you according to their own way.  But you might have developed some kind of interest while studing different subjects related to Computer science and you can make a Career from them. 

Career Options:

There are different Career options avilable after Computer Engineering and hence you have to keep looking for such organization that can help you in pursuing that.I'll just explain the overview for the particular option rather than diving into the details.

1. Software programmer/Developer: This is option which many computer engineers tends to go for but to be frank you need a good aptitude to be a developer. As a software Developer you are suppose to write the code in programming language like C, Java, .Net or PHP etc. You need to look for the requirement in the company and what kind of language they use for making their products and providing service. A fresher  can earn from 3-6 Lakhs per Annum depending upon the college he is from.

2. Software Tester: Software Testing is the onther imprtant aspect in creating and delivering software.  As a software Test engineer you need ensure that the software is working as expected and you are suppose to find different issues in the application. All and all , you are suppose to break the product or have to find the loopholes where it can break. You are paid to find bugs in the system.

3. Database Administrator (DBA):  Everyone knows about the imprtance of data and how much pain it creates when we loose it. And similarly the organization data is worth billions and hence they need people who can manage their data well and can get it when required to retrieve it. These data are stored in Databases.  Your main job is to create users profiles who can access that data, backup data, optimize the database for performance, etc.  For this you need to know about databases say :Oracle, SQL server, DB2 etc and language like SQL that the database understand.

4. Hardware Engineer: Yes many of us like to play with the hardware rather than software. Hardware Engineers take care of the company hardware inventory and they are suppose to handle the hardware issues which software people face while working on their system like replacing hard disk, network card or any other hardware related issues.

5. Network Engineer: This is one of the hottest profile in today's market. Networking is future and people are getting inclined towards Networking. As a Netowork Engineer you need to make sure that company can perform its network related functions properly. You may require to setup or support networks between different officies of the organization located in different part of the world and also to the external world. You may required to create a design about which kind of systems should organization use to set up their network and also about managing their different network devices.

6. Software sales: Many students are not aware about the opportunities available in the software sales department but then it is more of a non techincal job rather than technical. And then you need to be good in marketing which comes by experiance and also you need to have a proper understanding of the domain and the product you are about to sell to your customer. You may have to search a lot if you are a fresher in engineering. Mostly companies look for MBA's for such stuff.  Keep trying and look, who knows you might get lucky.

7. Software trainers/Technical Writers: After the software is sold to the customer, adequate training is required by the customer so that he uses the software efficiently and also if you are good at something you can join company's training department who are just like teachers and have to keep arranging learning stuuf for employees to keep their knowledge intatc.

8. Software support: There would be times where the software doesn't works as expected and thats where software support engineer is required.   As a support engineer you are suppose to solve technical queries related to products and process related to the system so that customers do not face any major issues if there is something goes wrong and even as a support engineer for the employees also.

So, these were the main career options you can choose from and hope you might find them useful. Hope it helps. Please leave the feedback and let me know in case you want more details.

You guys might be hearing the word cloud these days if you are into technology and many are in misconception that some big cloud above in the sky is storing our data, but you know that's quite funny and the strange part is that people who don't have even the slightest idea about it are taking like the real professional people who knows cloud from birth. If you don't believe me then do check out  the  video: Vishwa Bandhu Gupta Explains Cloud computing and after you are done with the laughs, come back to this article.

Ok, So what exactly is a Cloud

In simple layman's term : Cloud computing is the next stage in evolution of the Internet. The cloud in cloud computing provides the means through which everything - from computing power to computing infrastructure, applications, business processes to personal collaboration — can be delivered to you as a service wherever and whenever you need. 

Why do we need it

Because is the business demand. Its a model where everything is avilable everywhere and you not to be worried about the services and data just because you are not having your own device. You just need a device that can connect to the internet and cloud takes the responsibility of providing your data at that place. Because of its elastice nature cloud is becoming important. Means users can request additional resources on demand and just as easily release those resources when they’re no longer needed. 

Advantage

The cloud can eliminate many of the complex constraints from the traditional computing environment, including space, time, power, and cost.  The end user doesn’t really have to know anything about the underlying technology. He will get the service as per his requirement. He simply requests an amount of computing, storage, software, process, or other resources from the service provider. The simple example of Cloud service is your email account like : gmail.

Difference from Traditional IT Service Providers

Traditional IT service providers operate the hardware, software, networks, and storage for its clients. While the customer pays the licensing fees for  the software, the IT service provider manages the overall environment. The service provider operates the infrastructure in its own facilities. With the traditional IT service provider, the customer signs a long-term contract that specifies mutually agreed-upon service levels. These IT providers typicallycustomize an environment to meet the needs of one customer.

In the cloud model, the service provider might still operate the infrastructure in its own facilities (except in the case of a private cloud) however, the infrastructure might be virtualized across the globe, meaning that you may not know where your computing resources, applications, or even data actually reside. 

Problems

Yes every system has a problem and its not easy to implement cloud either. There is an inherent conflict between what the business requires and what data center management can reasonably provide. Business management wants optimal performance, flawless implementation, and 100 percent uptime. The business requires new capability to be available immediately, frequent changes to applications, and more accessibility to quality data in real time and at the samy time their organizations have limited budgets.

Finally

Well no one can gurantee that everything will be perfect when you or me get a cloud. The things, unfortunately, are more complicated than that. For example, complex, brittle applications won’t all be successful if they are just thrown up on the cloud. Virtualization adds performance implications. And many of these applications lack an architecture to achieve scale. A database-bound application will remain database bound, regardless of the additional compute resources beneath it.

Closing notes

My idea for writing this article is to get familiar with the term cloud and some of its points rather than diving into the technology part. But i would like to hear about your views and feedback in case you want to know more about the techincal details as the topic is very vast.

Enjoy..

These days Internet has become an important thing for many people. Even for most of the business this thing has become must. People just love to set wifi internet at their home so that they can share their one internet with their multiple devices. And having multiple devices and gadgets is normal thing now. So with that it has also become common that many times we face different wifi issues because of different reasons. There may be many different problems regarding this like slow wifi network, low signal, etc. And sometimes for that we need some expert to fix our problem regarding wifi network as we know nothing about fixing. But you know sometime this problem occurs because of minor issue and we can fix such problems with small changes and fixing all by our self. You don’t need to be expert for the same as you can fix it too by doing few changes in to it. Let’s learn about different solutions to fix our wifi network by our self.

Router Wires

You may not believe me. But sometimes even because of this minor thing we don’t get good wifi network. Just checkout wires of router if they are not loose. Just make sure they are fit into router properly. Also check out the quality of wire. If you don’t have good wire then it is possible that you don’t get proper wifi network or highest speed of internet what you should get normally. If possible then you can also change the power point from which you have connected your wifi router. Sometimes faulty power supply can also raise this kind of problems for you. So you don’t need to be expert for this at least. Just checkout it by yourself and it is possible that you can short out the problem in no time.

Router with two antennas

The speed and network of your wifi connection also depend on hardware of your router. In market there are routers with one and two antennas. It is obvious thing that you will get strong network by router with two antennas. So if you are having problem of low network and slow internet speed, and if you have router with one antenna then you need to upgrade your hardware. Just purchase the new router with two antennas and you will get strong network in compare to previous hardware. So hardware we are using for it is also important. And you can purchase it by yourself. If you know how to configure new router then it is okay otherwise you will need expert for the same.

Someone else using your network

If more devices are using the same wifi network then it is obvious that you will get slow internet. That means this thing can also cause you problem of slow internet. So make sure that your neighbors or other people around you are not using your wifi network. This problem can arise if you have not set the password to protect your wifi network. So make sure that you don’t forget to keep password for your network otherwise there are many around us who just love to use free internet.

Wifi blind spot at your home

When we are using wifi for internet purpose then this thing can possible. It is not possible to get same network in every place in our home. It may possible that at one place or in one room you won’t get any signal at all of wifi network. This thing called wifi blind spot. So make sure that you are not facing any issues like that. If you are facing such problem then make sure you avoid using internet from that place to avoid such problem. Otherwise you need to change the location of your wifi setup. So make sure you not facing any wifi blind spot problem.

Few odd windows settings can raise problem

I don’t know about other operating systems. But in windows operating system we are having power settings option which can raise wifi network problem. Because of power setting when your computer goes to power saving mode it also power down your wifi signal strength to save the battery of your computer. This can cause slow internet speed on your computer. So make sure you configure your power settings properly to avoid this kind of problem on your computer.

Drivers should be up to date

Do you know drivers of wifi network on your computer can also cause such kind of problems? Yes if you have outdated drivers for your wifi hardware on your computer then you can get slow internet speed. So make sure that you are using latest drivers for your hardware. You can checkout drivers of your wifi hardware from device manager in the windows computer. From the list of hardware just check out your wifi drivers and if they are outdated then just right click on it and click on update drivers option and it will automatically update drivers with help of interent. So don’t forget to keep your drivers up to date.

Wifi channels

For this thing you need to know the way of configuring your wifi network. If you don’t know how to configure it then you can call expert or the person who know this stuff to do this thing. There is wifi channel option in the configuration options. If you are having slow internet problem then you can change the channel of your wifi setup. After changing the channel, you just save all the settings and then check out. It is possible that this can solve your problem regarding slow internet connection. For this one you may need expert if you don’t know about configuring wifi network.

So this is it. I guess I have explained almost all the ways I know to sort out the problem regarding wifi network. Even if you can’t solve your problem after trying all above tricks then you seriously need an expert technician to sort out your problem. Otherwise if problem is minor then above tricks works most of the time. So be an expert (even if minor one) by yourself. This can help you in your emergency times. All the best.