UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
LECTURE NOTES
UNIX PROGRAMMING
Name Of The Programme B.Tech-CSE
Regulations R-16
Year and Semester III Year I Semester
Name of the Course Coordinator Mr A.Sandeep Kumar
Name of the Module Coordinator Dr.G.J.Sunny Deol
Name of the Program Coordinator Mr.N.Md.Jubair Basha
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
KALLAM HARANADHAREDDY INSTITUTE OF TECHNOLOGY
NH-5, Chowdavaram Village, Guntur, Andhra Pradesh, India
Approved By AICET, New Delhi, Permanently Affiliated to JNTUK
Kakinada Accredited By NBA, Accredited By NAAC with A Grade
ACADEMIC YEAR 2020-21
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 1
,UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
Unit-1
Introduction to unix-Brief History-What is Unix-Unix Components-Using Unix-
Commands in Unix-Some Basic Commands-Command Substitution-Giving Multiple
Commands
➢ Brief history:
Many schools have contributed to Unix development, but the initial contribution
by bell laboratory of AT and T and the university of California, Berkley are notable.
Bell laboratory contribution:
➢ In 1965 ,Massachusetts institute of technology(MIT),general electrical and bell
laboratories of AT & t worked on a joint venture project called multics, which intended
to develop a multi-user operating system.
➢ In 1969 ,AT&T withdraw itself from the multics project as the process was not
satisfactory.
➢ On the basics of the ideas acquired while working on multics, ken Thomson and Dennis
ritche developed an operating system(os) called UNICS (uniplex informatics and
computing system) during the latter part of 1969.
➢ UNICS was developed completely is assembly language and so it was not portable.
➢ To achieve portability, Thomson considered implementing the system in high level
language which leaded to the development of ‘c’ language by Ritche in 1973.
➢ Ritche completely recorded th entire unix system during the year 1973.
➢ In details of the unix implementation in’c’ was mode public through a paper published in
1974.
➢ A system called unix system V was announced in 1963.
➢ With this release AT&T assured the upward compatibility all its features releases.
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 2
, UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
➢ The most important of the releases is the system V release 4 (SUR4) in 1991.
UCB’s contribution:
➢ The team at Berkeley was responsible for many important technical contributions as
well as the development of useful utilities.
➢ The development of UCB towards unix are
➢ EX: editor, vi editor, c-shell (csh).
➢ Researchers at Berkeley labs were also released some BSD-unix (Berkeley
software distribution ) during the spring of 1978.
➢ These BSD releases are 4.0 BSD(1980), 4.1 BSD(1981), 4.2 BSD(1983), 4.3 BSD(1986)
and 4.4 BSD (1993).
Why so many variants:
➢ One of the main reasons for many variants of unix is that being a telephone
company, At& T was not permitted to sell computer-based products.
➢ However, it could do so free of cost or for a nominal. BSD was also giving its
products for free of cost , many obtained the copies of unix and worked on them
.This resulted in a number of unix variants.
➢ Another important reason was that these systems were developed mostly by
researchers for researchers and revised constantly to suit different requirements of
many unix variants.
What is unix:
➢ Unix is an operating system .
➢ An operating system is a software that acts as an interface between the user and
computer h/w.
➢ An operating system acts as a resource manager.
➢ Here resources mean hardware resources like the processor, the main memory, the
hard disk, i/o devices and other peripherals.
➢ In addition to being a multi-user operating system unix gives its users, the feeling of
working an independent computer system.
Unix also provides communication facility with other users who are connected to the
system either directly or indirectly via certain sort of networking
Sailent features of unix:
1. Multi- tasking:
➢ Unix is a multi-tasking operating system.
➢ It has the ability to support concurrent execution of 2 or more active process
(instance of program in execution is called process).
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 3
, UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
2. Multi-user operating system:
➢ Unix is multi-user operating system.
➢ It has ability to support more than one user to login into the system
simultaneously and execute programs.
Difference: the diiference between multi –tasking and multi-user
system is,
• In multi-tasking, different tasks the process running concurrently
belongs to one user.
• In multi-user environment different tasks belong to diff users.
3. Portable
➢ Unix operating system is highly portable.
➢ Compared to other os, it is very easy to port.unix on to different
hardware platforms with minimal or no modifications at all i.e.,
because it ways developed in c language which is high level language
4. Inter machine communication:
➢ The development of communication protocols like tcp/ip has made possible
by unix operating system to usera to exchange information in the form of email
and shared data.
5. Security:
➢ As Unix is multi-user system, there is every chance that a user may
intrude into a another users area either unintentionally. But, Unix offers
solid security at various levels beginning from the system startup level to
accessing files as well as saving data in an encrypted form.
6. Library of utility and commands:
➢ Unix has good library of utilited and commands that have been used to
develop newer applications.
7. File and directory system:
➢ One of the very important key feature of any unix system is that allows users
to organize and maintain these files/directories easily and maintain these
files/directories easily and efficiency.
UNIX components:
Unix contains 3 major components.
1. The kernel
2. The shell
3. The file system.
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 4
LECTURE NOTES
UNIX PROGRAMMING
Name Of The Programme B.Tech-CSE
Regulations R-16
Year and Semester III Year I Semester
Name of the Course Coordinator Mr A.Sandeep Kumar
Name of the Module Coordinator Dr.G.J.Sunny Deol
Name of the Program Coordinator Mr.N.Md.Jubair Basha
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
KALLAM HARANADHAREDDY INSTITUTE OF TECHNOLOGY
NH-5, Chowdavaram Village, Guntur, Andhra Pradesh, India
Approved By AICET, New Delhi, Permanently Affiliated to JNTUK
Kakinada Accredited By NBA, Accredited By NAAC with A Grade
ACADEMIC YEAR 2020-21
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 1
,UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
Unit-1
Introduction to unix-Brief History-What is Unix-Unix Components-Using Unix-
Commands in Unix-Some Basic Commands-Command Substitution-Giving Multiple
Commands
➢ Brief history:
Many schools have contributed to Unix development, but the initial contribution
by bell laboratory of AT and T and the university of California, Berkley are notable.
Bell laboratory contribution:
➢ In 1965 ,Massachusetts institute of technology(MIT),general electrical and bell
laboratories of AT & t worked on a joint venture project called multics, which intended
to develop a multi-user operating system.
➢ In 1969 ,AT&T withdraw itself from the multics project as the process was not
satisfactory.
➢ On the basics of the ideas acquired while working on multics, ken Thomson and Dennis
ritche developed an operating system(os) called UNICS (uniplex informatics and
computing system) during the latter part of 1969.
➢ UNICS was developed completely is assembly language and so it was not portable.
➢ To achieve portability, Thomson considered implementing the system in high level
language which leaded to the development of ‘c’ language by Ritche in 1973.
➢ Ritche completely recorded th entire unix system during the year 1973.
➢ In details of the unix implementation in’c’ was mode public through a paper published in
1974.
➢ A system called unix system V was announced in 1963.
➢ With this release AT&T assured the upward compatibility all its features releases.
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 2
, UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
➢ The most important of the releases is the system V release 4 (SUR4) in 1991.
UCB’s contribution:
➢ The team at Berkeley was responsible for many important technical contributions as
well as the development of useful utilities.
➢ The development of UCB towards unix are
➢ EX: editor, vi editor, c-shell (csh).
➢ Researchers at Berkeley labs were also released some BSD-unix (Berkeley
software distribution ) during the spring of 1978.
➢ These BSD releases are 4.0 BSD(1980), 4.1 BSD(1981), 4.2 BSD(1983), 4.3 BSD(1986)
and 4.4 BSD (1993).
Why so many variants:
➢ One of the main reasons for many variants of unix is that being a telephone
company, At& T was not permitted to sell computer-based products.
➢ However, it could do so free of cost or for a nominal. BSD was also giving its
products for free of cost , many obtained the copies of unix and worked on them
.This resulted in a number of unix variants.
➢ Another important reason was that these systems were developed mostly by
researchers for researchers and revised constantly to suit different requirements of
many unix variants.
What is unix:
➢ Unix is an operating system .
➢ An operating system is a software that acts as an interface between the user and
computer h/w.
➢ An operating system acts as a resource manager.
➢ Here resources mean hardware resources like the processor, the main memory, the
hard disk, i/o devices and other peripherals.
➢ In addition to being a multi-user operating system unix gives its users, the feeling of
working an independent computer system.
Unix also provides communication facility with other users who are connected to the
system either directly or indirectly via certain sort of networking
Sailent features of unix:
1. Multi- tasking:
➢ Unix is a multi-tasking operating system.
➢ It has the ability to support concurrent execution of 2 or more active process
(instance of program in execution is called process).
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 3
, UNIX PROGRAMMING B.Tech(CSE) III Year I Sem
2. Multi-user operating system:
➢ Unix is multi-user operating system.
➢ It has ability to support more than one user to login into the system
simultaneously and execute programs.
Difference: the diiference between multi –tasking and multi-user
system is,
• In multi-tasking, different tasks the process running concurrently
belongs to one user.
• In multi-user environment different tasks belong to diff users.
3. Portable
➢ Unix operating system is highly portable.
➢ Compared to other os, it is very easy to port.unix on to different
hardware platforms with minimal or no modifications at all i.e.,
because it ways developed in c language which is high level language
4. Inter machine communication:
➢ The development of communication protocols like tcp/ip has made possible
by unix operating system to usera to exchange information in the form of email
and shared data.
5. Security:
➢ As Unix is multi-user system, there is every chance that a user may
intrude into a another users area either unintentionally. But, Unix offers
solid security at various levels beginning from the system startup level to
accessing files as well as saving data in an encrypted form.
6. Library of utility and commands:
➢ Unix has good library of utilited and commands that have been used to
develop newer applications.
7. File and directory system:
➢ One of the very important key feature of any unix system is that allows users
to organize and maintain these files/directories easily and maintain these
files/directories easily and efficiency.
UNIX components:
Unix contains 3 major components.
1. The kernel
2. The shell
3. The file system.
Prepared by Mr.A.Sandeep Kumar, Assoc.Prof , CSE DEPT,KHIT Page 4
