UNIX® License PlateUNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.
UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session. Types of UNIX
The Linux PenguinThere are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.
Here in the School, we use Solaris on our servers and workstations, and Fedora Linux on the servers and desktop PCs. The UNIX operating system
The UNIX operating system is made up of three parts; the kernel, the shell and the programs. The kernel
The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls.
As an illustration of the way that the shell and the kernel work together, suppose a user types rm myfile (which has the effect of removing the file myfile). The shell searches the filestore for the file containing the program rm, and then requests the kernel, through system calls, to execute the program rm on myfile. When the process rm myfile has finished running, the shell then returns the UNIX prompt % to the user, indicating that it is waiting for further commands. The shell
The shell acts as an interface between the user and the kernel. When a user logs in, the login program checks the username and password, and then starts another program called the shell. The shell is a command line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The commands are themselves programs: when they terminate, the shell gives the user another prompt (% on our systems).
The adept user can customise his/her own shell, and users can use different shells on the same machine. Staff and students in the school have the tcsh shell by default.
The tcsh shell has certain features to help the user inputting commands.
Filename Completion - By typing part of the name of a command, filename or directory and pressing the [Tab] key, the tcsh shell will complete the rest of the name automatically. If the shell finds more than one name beginning with those letters you have typed, it will beep, prompting you to type a few more letters before pressing the tab key again.
History - The shell keeps a list of the commands you have typed in. If you need to repeat a command, use the cursor keys to scroll up and down the list or type history for a list of previous commands.
Files and processes
Everything in UNIX is either a file or a process.
A process is an executing program identified by a unique PID (process identifier).
A file is a collection of data. They are created by users using text editors, running compilers etc.
Examples of files:
a document (report, essay etc.) the text of a program written in some high-level programming language instructions comprehensible directly to the machine and incomprehensible to a casual user, for example, a collection of binary digits (an executable or binary file); a directory, containing information about its contents, which may be a mixture of other directories (subdirectories) and ordinary files.
The Directory Structure
All the files are grouped together in the directory structure. The file-system is arranged in a hierarchical structure, like an inverted tree. The top of the hierarchy is traditionally called root (written as a slash / )
Unix File Structure
In the diagram above, we see that the home directory of the undergraduate student "ee51vn" contains two sub-directories (docs and pics) and a file called report.doc.
The full path to the file report.doc is "/home/its/ug1/ee51vn/report.doc" Starting an UNIX terminal
To open an UNIX terminal window, click on the "Terminal" icon from Applications/Accessories menus.
An UNIX Terminal window will then appear with a % prompt, waiting for you to start entering commands.
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1. Free Government job study material, old question papers, and mock tests. Here are some of the freely available Government job study material, old question papers, and mock tests.
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2. What is the difference between NPR and Population Census? What is the difference between NPR and Population Census?
The recent news about the Cabinet ministry’s fund approval for NPR Census has created confusion among people about these terms. Often used interchangeably, both the terms have completely different meanings. Let’s understand in detail through this article.
After the cabinet today approved an amount of Rs. 8700 crores for population census an Rs. 3900 crore for NPR (National Population Register), a lot o
3. General Knowledge Questions - 12 General Knowledge Questions - 12
Q. Which organisation or bodies decides monetory policy in India?
Answer: RBI Reserve Bank of India.
Q. Which is the largest country of AFRICA?
Q. What type of pollution is caused by the burning of fossil fuels?
Answer: Soil, water and air pollution.
Q. At first paper is invented in which country?
Q. What is the full form of "DBMS"
4. General Knowledge Questions - 1 General Knowledge Questions
1. Blood does not coagulate so long it remains in the circulatory system because of-
A. Pressure of heparin in blood.
B. Pressure of blood.
C. Presence of iron pigments in blood.
D. Constant heart beat.
2. Indian Constitution came into force from-
A. 26th January, 1949
B. 26th November, 1949
C. 26th January, 1950
D. 26th November, 1950
5. About Right to Information Act 2005 About Right to Information Act 2005
Bringing Information to the Citizens
Right to Information Act 2005 mandates timely response to citizen requests for government information. It is an initiative taken by Department of Personnel and Training, Ministry of Personnel, Public Grievances and Pensions to provide a– RTI Portal Gateway to the citizens for quick search of information on the details of first Appellate Authorities,PIOs etc. amongst others, besides access
6. General Knowledge Questions - 8 General Knowledge Questions - 8
1. Who was recently appointed as the interim president of BCCI-
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B. Sunil Gavaskar
C. Sashant Manohar
D. Ravi Shastri
2. In Idnia, due to the influence of retreating monsson, rainfall occurs in the-
A. Coromondol Coast
B. Northern circars coast
C. Konkon Coast
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3. The pale yellowish color of the urine in a normal per
7. Vidyapati (1352–1448), Vidyapati (1352–1448), also known by the sobriquet Maithil Kavi Kokil (the poet cuckoo of Maithili), was a Maithili and Sanskrit poet, writer and polyglot.
Vidyapati's influence was not just restricted to Maithili and Sanskrit literature but also extended to other Eastern literary traditions.The language at the time of Vidyapati, the prakrit-derived late abahatta, had just begun to transition into early versions of the Eastern languages such as Maithili, Bhojpuri etc.
8. General Knowledge Questions - 6 General Knowledge Questions - 6
1. The name of the Indian cricketer who taken ten wickets in one innings of a test cricket match(for men)
A. B.S. Bedi
C. Kapil Dev
D. Anil Kumbley
2. Ecology is the study of interrelations among-
A. Soil and water
B. Man and Environment
C. Organisms and environment
D. Members of a family
3. The world famous athlete Usain Bolt is fro
9. NISHTHA | National Portal of India
NISHTHA | National Portal of India
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12. Does Complex Numbers / Imaginary number i exists?? Does Complex Numbers / Imaginary number i exists??
People studying Higher Mathematics are often confused with the existence of Complex Numbers and its Imaginary number “i”.
What are Complex Numbers:
Complex Numbers are numbers whose 1st part is Real while 2nd part is Imaginary and is expressed as a+bi
a –> Real Part
bi –> Imaginary Part and
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14. Top 10 Indian Mathematicians and their Contributions It is no doubt that the world today is greatly indebted to the contributions made by Indian mathematicians. One of the most important contribution made by them was the introduction of decimal system as well as the invention of zero. Here are some the famous Indian mathematicians dating back from Indus Valley civilization and Vedas to Modern times.
15. Computer – Some Important Abbreviations Computer – Some Important Abbreviations
Al – Artificial intelligence
ALGOL – Algorithmic Language
ARP – Address resolution Protocol
ASCII – American Standard Code for Information Interchange
BINAC – Binary Automatic Computer
BCC – Blind Carbon Copy
Bin – Binary
BASIC – Beginner’
16. Vaccines and Immunization | Facts and Information Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual's immune system to develop adaptive immunity to a pathogen. Vaccines can prevent or ameliorate morbidity from infection. When a sufficiently large percentage of a population has been vaccinated, this results in herd immunity. The effectiveness of vaccination has been widely studied and verified; for example, the influenza vaccine, the HPV vaccine, and the chicken pox vaccine. Vaccination is the most eff
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18. National Pollution Control Day The National Pollution Control Day is celebrated every year on 2nd of December in India in order to give the honor and memorialize the thousands of human beings who had lost their existence because of the Bhopal gas calamity. Bhopal gas tragedy was happened in the night of 2nd and 3rd December in the year 1984 because of the unintentional discharge of the poisonous chemical known as Methyl Isocyanate (also called MIC) as well as some other chemicals released from the Union Carbide Chemical Plant position
19. MULTIPLE CHOICE QUESTIONS ON COMPUTER AWARNESS MULTIPLE CHOICE QUESTIONS ON COMPUTER AWARNESS
Which of the following is a storage device that uses rigid, permanently installed magnetic disks to store data/information
A set of instruction is called
20. Education in Bihar Education in Bihar
The Ancient Period
The appreciation of the importance of education and educational practices in Bihar
date back to the period of Gautama Buddha and Mahavir in the 5th century BC. During that period, the Buddhist and Jainist education started in parallel with the traditional Vedic education. The Buddhist education was based on the Ashtangic (eight-fold) Path, and its distinguishing features were: the introduction of
21. Right to Information Right to Information is an Act of the Parliament of India to be responsible for setting out the practical rule of the right to information for citizens and substitutes the past Freedom of information Act, 2002. If you are familiar with the RTI concepts, wiling to change the career into RTI field, then we in Wisdomjobs have provided you with all kinds of interview question and answers that you are going to get in the RTI. You can apply to the government jobs if you are good at RTI. If you are good at RTI
23. Statue of Unity: The Tallest Statue in the World There are many more feathers that can be added to the cap when it comes to the Statue of Unity- scheduled to be inaugurated on 31st of October. Standing at a mouth-gaping height of 182 meters, this statue of Sardar Vallabhbhai Patel is a good 54 meters taller than the Spring Temple Buddha (China). The latter is now the second largest statue in the world.
While the statue is one of PM Modi’s treasured projects, it hasn’t always escaped controversies. Nonetheless, it is the talk of th
24. RRB ALP Answer Key 2018 RRB ALP Answer Key 2018
Railway Recruitment Board is going to conduct the First Stage Computer Based Examination for the selection of ALP/ Technician as per the advertisement no CEN-01/2018. The Recruitment Notification was released for filling up 26502 posts of ALP Technician in various RRBs all over the country and a huge number of candidates filled up the online application for appearing in CBT. The date of Computer Based Examination has been fixed now by the RRB
25. Tips For Students: How to Take Good Notes for Studying Taking good notes throughout the semester may mean the difference between simple study sessions or decoding sessions later on. Your time is too valuable for you to just sit in class, day after day, only going through the motions of taking notes.
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Stay focused in class
27 UPSC Combined Defence Services Examination (CDS) (I) 2021#UPSC1 Days Remaining for Apply The Union Public Service Commission (UPSC) will hold the Combined Defence Services Examination (CDS) (II), 2020 on 7th February 2021 for admission to Indian Military Academy, Dehradun, Naval Academy, Ezihimala, Air force Academy, Hyderabad, and Officers Training Academy, Chennai for the courses (Men and Women) for recruitment of following 345 Sarkari Naukri Vacancy of Officers in Navy, Army, and Indian Air Force. (UPSC Advt. No. 2/2021.CDS-I)
Online application on prescribed format i ...
28 Combined Higher Secondary (10+2) Level Examination 2020 by SSC#SSC16 Days Remaining for Apply Combined Higher Secondary (10+2) Level Examination 2020 by SSC
The Staff Selection Commission (SSC) will hold an open competitive Computer Based Combined Higher Secondary (10+2) Level (CHSL) Examination 2020 from 12/04/2020 to 17/04/2020 for Recruitment of various Group-C Government Jobs (Sarkari Naukri) Vacancy (Tier-I) for various Ministries/ Departments/ Organizations in the Government of India.
29 ICMR Assistant Vacancy Recruitment 2020 #Scientist & Research4 Days Remaining for Apply Indian Council of Medical Research (ICMR), New Delhi has entered into a memorandum of understanding with the Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh for holding of Computer Based Test (CBT) Recruitment Examination/Test for Sarkari Naukri Vacancy posts of Assistants (Group-B Level-6) of ICMR by PGIMER, Chandigarh.
30 UP PSC Regional Inspector (Technical) Examination 2020#Uttar Pradesh4 Days Remaining for Apply UP PSC Regional Inspector (Technical) Examination 2020
Online applications on the prescribed format are invited by Uttar Pradesh (UP) Public Service Commission (PSC), Prayagraj for Recruitment of Government Job (Sarkari Naukri) Vacancy posts of Regional Inspector (Technical) (सम्भागीय निरीक्षक (प्राविधिक)) under Regional Inspector (Technical) Examination 2020 for Transport Department of Government of Uttar Pradesh (Advt. No.: A- ...
39 India Post GDS Recruitment 2020 for Jharkhand North-East Punjab states#Jharkhand12 Days Remaining for Apply Online applications in the prescribed format are invited by Jharkhand, North-East, and Punjab Circles of Indian Postal Department from eligible candidates for the recruitment selection and engagement to the Government Job vacancy posts of Gramin Dak Sevak (GDS) under Cycle-III/2020-2021 in the posts offices of the respective circles in the states in Jharkhand, North-East and Punjab states. (Advertisement Numbers - GRAMIN DAK SEVAKS CYCLE – III/2020-2021)
43 Lecturer Technical Education Vacancy Recruitment by RPSC 2020#Rajasthan28 Days Remaining for Apply Rajasthan Public Service Commission (RPSC) invites Online application on prescribed format for the recruitment for the following Faculty Sarkari Naukri vacancy of Lecturer Technical Education for Rajasthan Technical Education Department of Rajasthan Government (Advt. No. 05/EP-I/2020-21).
Rajasthan PSC recruitment examination requires hard work, dedication, and extensive study. The d ...