unix environment [autosaved]

UNIX ENVIRONMENT

DESIGNED BY :MITTINPREET SINGH NAYYARVIKAS K PRASAD

Introduction to Unix History of Unix Salient features of Unix SHELL Distributions Installing VMware Basic Unix Commands Q&A References

Roadmap

INTRODUCTION TO UNIX

A multi-tasking and multi-user Operating System Developed in 1969 at AT&T’s Bell Labs by

Ken Thompson (Unix) Dennis Ritchie (C) Peter Neumann suggested their project is given the name UNIX.

It is a portable operating system that is designed for both efficient multi-tasking and multi-user functions. Its portability allows it to run on different hardware platforms. It was written is C and lets user do processing and control under a shell.

Unix is case sensitive

HISTORY OF UNIX

The history of UNIX starts from the project MULTICS (Multiplexed Information and Computing Service) in 1965 conducted by AT&T,GE & MIT funded by DOD(Dept. of Defense)USA.

The main aim to develop UNIX was to develop and operating system that could serve large Community of users and allow them to share data if needed be. This never to be enterprise called MULTICS

In 1969, ken Thompson and Dennis Ritchie released the first version of Multiuser System Called UNIX. At that time Unix was not portable. To remedy this Ken Thompson created a new language “B” but language lacked some aspects. So in 1973 UNIX was Rewritten in “C” Language by Ken Thompson. C Language was developed by Dennis Ritchie.

SALIENT FEATURE OF UNIX

Multiuser Capability Multitasking Capability Communication Security Portability

What is SHELL

A shell acts as an interface between the user and the system. As a command interpreter, the shell takes commands that we give interpret the command and then conveys them to the kernel which ultimate executes them. You can imagine kernel as a monarch who is the overall control of everything where as the shell as its emissary

TYPES Of SHELLS BOURNE SHELL Steve Bourne Creation, known after him Bourne Shell is the most popular. It comes with every Unix System C SHELL This shell is a hit with those who are seriously into Unix programming, created by Bill Joy, it had two advantage over Bourne Shell. It allows aliasing of commands the other one is history feature. KORN SHELL it is not widely used but is a powerful and superset of Bourne shell, created by David Korn.OTHER SHELLS ZSHELL BASH SHELL

SHELL Prompt of Ubuntu

To open the terminal in Ubuntu use can use the shortcut : ctrl + Alt + T

DISTRIBUTIONS Linux

Minix FreeBSD OpenBSD NetBSD GNU Hurd Solaris SCO Unix

ConclusionThere are many free Unix like operating systems floating around out there and most if not all of them can be found quickly with a simple internet search. The OS's I have listed above are, in my opinion, the best. They are also all available to use for free unlike most of the others.

http://www.distrowatch.com

Ubuntu Distribution

BASIC COMMANDS

This command returns your username. Sounds useless, but isn't. You may need to find out who it is who forgot to log out somewhere, and make sure *you* have logged out.Example: whoami

whoami

Man - Manual

In unix online help has been available since the beginning. In order to access all the available help, you have to tell the shell where to look for online help pages. This information is specified using the MANPATH. A common setting is:MANPATH=/usr/man:/usr/share/manWhen you use the man command to request online help as follows, the man command searches every directory given in the MANPATH for an online help page corresponding to the topic you have requested.

$man whoIn this case it looks for the online help page corresponding to the who command

A snapshot of $man who

Passwd

To change the password of the user we use passwd command Which ever password we create Unix stores it in /etc/passwd file. The password actually stored in Shadow File which is located in

etc/shadow. We can even cat this file on the screen lets you change your password, which you should do regularly (at

least once a year).$cat /etc/passwd

cal - Calender

Display a conveniently-formatted calendar from the command line.In general, if no options are given, cal displays the current month at the command line.

Touch

With this command we will learn how to create files With this we can create many files without storing anything in

the files. The size of the file is ZERO Bytes Q Why do we use touch ?A when we want to create several files quickly we use touch command.

Example: touch dinesh heena siddhi jatin

cat- concatenate

If we want to store a few lines in a file while creating it we use cat command. One’s you are through with typing content press the keys : Ctrl + d . In Unix Ctrl + d indicates the EOF(End of File)

To display the content of file under DOS we use type command. To see content of file we use the following command Umask 0022Example : cat >dheeraj - for creating filecat < dheeraj or cat dheeraj - will show you the output

cp- copyCopies Files from one Directory or location to another file or directory.Cp command takes the liberty to overwrite the file to the destination it will not even give a warning.

Example:$cp abc.c xyz.c mycfile.txt$cp abc.c xyz.c $cp /usr/aa16/chapter1 /usr/aa16/newbook/chap1

The last command when executed it will copy the chapter1 file to /usr/aa16/newbook. When copied to this directory it would have the name chap1 instead of chapter1

rm - remove

Remove Files from directory. It is wise to use the option rm -i, which will ask you for confirmation before actually deleting anything.

Ls-list

ls --- lists your files ls -l --- lists your files in 'long format', which contains lots of useful information, e.g. the exact size of the file, who owns the file and who has the right to look at it, and when it was last modified. ls -a --- lists all files, including the ones whose filenames begin in a dot, which you do not always want to see. There are many more options, for example to list files by size, by date, recursively etc.

mv - move or rename

moves a file (i.e. gives it a different name, or moves it into a different directory

Chmod- change mode

mkdir – make directory

cd – change directory

Pwd- print working directory

rmdir – remove directory

logname

uname

who

tty – tele terminal

ulimit

sort

wc

Head

tail

more

shows the first part of a file, just as much as will fit on one screen. Just hit the space bar to see more or q to quit. You can use /pattern to search for a pattern.

less

date

Shows the current date and time.

References

Unix Shell Programming By Yashavant Kanetkar. Unix Concept and Application by Sumitabha Das. http://www.tutorialspoint.com/unix https://

www.youtube.com/watch?v=nVt3Rst-2H8&list=PL7B7FA4E693D8E790

Q&A SESSION