Tutorials On Unix Systems Computer Science Essay window.addEventListener...

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The motive of this website is to help's and better understanding the basic Unix concept for the beginner of UNIX's. This helps to the students as well as Industrial professionals who have zero knowledge about the Unix. Website includes step by step approach that covers most of the basic need of unix to work on it. After every topics there is a review section which helps to recall about the topic recently covered very quickly. Review includes the most commanly used commands that are being used normally.

I have used professor java script for nevigation bar that is a part of proff homepage.

I have used HTML5 and CSS3 for this website to create few tables. Table doesn't supported by crome browser. Firefox is OK for this website

About Website

Basic Design

I followed the 'CRAP' principle to design the website of UNIX tutorials. I am also looking forward to implement a search engine at the right corner of the navigation bar. I also using color scheme generator to shade. I used java script code from prof. Sonstein home page to design drop down menu of navigation bar.

Organization of information

I used Pseudo anchoring to display the content of pages. All the pages are stacked to each other and hidden the other. Only called page will be visible. Data is represented in each page to make a clear view about the topics

Content The content of this website will helps to the beginners and for those professionals who are out of touch with UNIX flavor. I emphasized to provide most commonly used commands and basic knowledge of the UNIX. Navigation Global and local navigation is used. I also used drop down menu from horizontal menu. Use of XHTML and CSS I designed each page using HTML (XHTML 5.0) and CSS (CSS 3.0). Pages are validated HTML 5 and getting issues in CSS3 as radius property is not available in CSS 2.1 but is present in CSS 3.0.

About Unix

A Unix ia a program initially written in assembly language and then later on in C language that controls the software and hardware part of the computer. Technically speaking, it is an operating system that perform multitasking by multiple users at a same time. Dennis Ritchie, a computer scientist who invent two cool things that I like's most. One is C programming language and other is Unix operating system at AT & T lab. He is graduated from Harvard University in physics and applied mathematics. Cool thing about unix is that, it is written in C programming language instead of other language like assembly language. It is a hardware independent operating system, means software and application can be switched from one machine to another. Let me talk about few things about the cool guy, Dennis Ritchie: born on September 9,1941, in Bronx-ville, New York and grew up in New Jeresy. He was good in academic under high school, and then got admission into Harvard University as a freshman. He graduated in physics as a bachelor's degree. He was fascinated by by everyhinigs that he heard and wanted to find out more. Apart from academic courses and classes he started look into computers more thoroughly, and trying to figure out how they were programmed.

Unix history

Unix was initially called Unices which means multies that support multiple users and multiple tasks simultaniously. In 1970, Unix operating system came into market officially and ran on the PDP-11/20. It added a text formatting program called roff and a text editor. Unix was written first in assembly language. Later on in 1972 Unix was again written in C language, which make Unix more portable operating system that deals with time critical event. Unix (for general perpose) came into market in 1980 with many different version's. But AT & T keep using the older verson also to avoid confusion between all its new and old versons which includes few new features like the vi editor, like file locking, system administration, STREAMS, new forms of IPC, the Remote File System and TLI.

Unix Component's

Unix has three components:kernel Shell Program kernel Kernel is a core component of Unix Operating System that initialize and instantiate at loading time and remain in main memory. All the programs running on system uses kernel/. Strictly speaking, kernal allocate the system memory to each program to run. It is also responsible for transfer the data from one machine to other. Kernel ats as a administration to give access and permission for file and folder. It interpret and execute instructions from the shell. Shell Shell is a middle layer between Program and kernel. It authenticate user and take users credientials to kernal for access. It takes commands from users and pass it to the kernel to process and display result on screen. It is basically a command prompt window that pop up by hitting "cmd" on run. Program Unix has an instance called process with a unique process Id called UID. Process use MVS (Multivolume file System) address space to execute. It is instantiated with the help of following functions like C fork() function (child process identical to parent) etc.

Directory structure

Files and folders are maintained in directory stucture in a hierarchial form of inverted tree starting with root. From the above fig. It is clear that out of several sub-directories user can store his own personal data in the home sub-directory. If you look at under the home sub-directory, user nxn1808(mine) has his own access followed by user personal directory. To go to the folder created by user, shut a command in the unix "cd /home/nxn1808/(folder)". We will talk more about Unix basic commands in details later.

_

Basic Command's

Here, I am login into one unix server and running few commands into my account of that server. Once you login into any server, you will be into your home directory. ls: ls command is used to look into the list of file, folders and directories of your current directory. ls -(X): This command gives you a list of desired items you want where X is a variable which is given by the user as per the his wish. Values of X's with details are as follow : a - listing all files and directories A - almost-all Or print author of files as well. b -print octal escapes for nongraphic characters B- do not list implied entries ending with ~ C -list entries by columns d -list directory entries instead of contents D -generate output designed for Emacs' dired mode g - list with a group name G -inhibit display of group information h- list sizes in human readable format H -follow symbolic links on the command line l- use a long listing format man ls- will give you list of all commands associated with ls

Review's

In this section we will do some practice to make the most important commands memorable for ever

Match the following

Cmd

Meaning

[G]

do not list implied entries ending with

[d]

list directory entries instead of contents

[A]

list directory entries instead of contents

[man ls]

list entries by columns

[h]

list sizes in human readable format

[b]

generate output designed for Emacs' dired mode

[l]

use a long listing format

[H]

follow symbolic links on the command line

[g]

list with a group name

[C]

print octal escapes for nongraphic characters

[a]

listing all files and directories

[G]

inhibit display of group information

[B]

will give you list of all commands associated with ls

[D]

almost-all Or print author of files as well.

File Command's

mkdir: mkdir command will create a directory into the current position.we can assign permission to this directory at the time of creation of directory. We will talk more about assigning permission later. mkdir -p: command helps us to change a parent directory as required if and only if we are not getting error while doing error. cd directory: cd command allow you to go to another directory directly where ever you want to go, eg. cd nitin/public/ project/www/737. cd . : Command give's you a current directory cd ~: This will bring you to home-directory cd ..:This command will kick you back to parent directory pwd : Shows the current directory path cp file1 file2 This command is used to copy a file1 to other place and named it as file2. You can copy this file into different directory also. For doing this you need to give a complete path of the concern directory where you want to copy. mv file1 file2 This command is used to cut-paste of the file to another location or rename of file1 to file2. rm file Command for removing a file from directory. There are few constraints for removing a directory, like we should make sure that directory is not deeting cascading. cat file : Command display the contents of of file head file command gives you back the first few lines of the file to make user a quick idea of what this file is all about. This command is more popular in real world applications where users do not want o go through all of the contents. tail file This command is just reverse of the head file which gives you back the last few lines of the contents of file. wc file Command will give you an integer value of the count of lines, words and characters in the file.

Review's

In this section we will do some practice to make the most important commands memorable for ever. Please do this exercise as a paart of the course. This will bring in you a confidence on Unix.

Match the following

Cmd

Meaning

[cp file1 file2]

command helps us to change a parent directory

[mv file1 file2]

Command display the contents of of file.

[pwd]

Command give's you a current directory

[man ls]

command is just gives you back the last few lines of the contents

[cd.]

Command give's an integer value of the count of lines, words and characters

[rm file]

command allow you to go to another directory directly

[cd..]

command gives back the first few lines to make user a quick idea about file

[cd~]

This command will kick you back to parent directory

[cat file]

This will bring you to home-directory

[tail file]

Command for removing a file from directory

[cd]

command is used to copy a file1 to other place

[head file]

Command display the path of the current directory

[mkdir]

command is used to cut-paste of the file to another location

[mkdir-p]

command will create a directory into the current position.

Adv. Command's

command > :This will sent back the output to file. command >>:This will append output to file. cat file1 file2 > file0: concatenate file1 and file2 to file0 command file redirect standard input from a file sort data. cmp:states whether or not the files are the same. diff: lists line-by-line differences. chmod:File change access rights for named file. ^C: kill the job running in the foreground. ^z: suspend the job running in the foreground. fg %1: number # 1 forground job. kill %1: killing job of number 1. kill 26152: Dead process of number 26152

Review's

In this section we will do some practice for advanced command's to used to these commands. Please do this exercise as a part of the course. This will bring in you a confidence on Unix.

Match the following

Cmd

Meaning

[chmod]

redirect standard output

[kill 26152]

Kill process number #

[fg %1]

append standard output

[kill %1]

kill job number 1

[^C]

foregroung job number 1

[^z]

kill the job running in the foreground

[comm]

suspend the job running in the foreground.

[diff]

displays lines in file 1 only, file 2 only, and both files

[cmp]

line-by-line differences.

[command]

[command>>]

Commands for other's

w: It ia a kind of administrative job to check who's logged in, and what they're doing. In corporate world client can use this to see whether employee are actually sitting and working on system and typing away at their keyboards right at the moment. who: Useful command to track your friend if he is actually physically in the same building as you, or in some other particular location. Also tells you who's logged on, and where they're coming finger username: This command is work to track punch in-out time or log In/Out time with a lots of information about a particular user, e.g. when they last read their mail and whether they're logged in. Profile information, such as phone numbers and addresses also pulled up last -1 username Provide information of the user when he last logged on and off and from where. If we simplyWithout any options, last will give you a list of everyone's logins. talk username : This will help you to chat with another user with the help of username. You can add multiple user into conversation. write username: This allows you to write a formal and informal message to another user that need to keep save into machine. This is also like talk username command except we can store the concersation between the users.

Review's

In this section we will do some practice for advanced command's to used to these commands. Please do this exercise as a part of the course. This will bring in you a confidence on Unix.

Fill up the blank place that match the meaning for the word on left

Cmd

Meaning

.......

....................................................................

[Who]

[finger username]

[w]

[last -1 username]

[write username]

[talk username]

Access

Unix operating system provide a authenticationand login facility to each user which is associated to a group. user can be a member of more than one group. Each directory, folder and files had a previlege assiged by admin. A set of permission flags which specify separate read, write and execute permissions for the 'user' (owner), ' group', and 'other'. ls command shows the permissions and associated group. Output produced by 'ls -1': All Unix users must understand this output especially people using group access permissions. Field 1: permission flags Field 2:link count Field 3:file owner Field 4:file associate with group Field 5:size (bytes) Field 6-8:modification date Field 9:file name

Permissions

Admin has the power and access to give permission to user(owner/group /others) for read, write and execute command on unix window ls command let you know the permissions and group.

2,3,4:read, write, execute permission for User (Owner) of file 5,6,7:read, write, execute permission for Group 8,9,10:read, write, execute permission for Other

value Meaning

-   in any position means that flag is not set r   file is readable by owner, group or other w   file is writeable. On a directory, write access means you can add or delete files x   file is executable. Execute permission on a directory means you can list the files in that directory

Review's

In this section we will do some practice for advanced command's to used to these commands. Please do this exercise as a part of the course. This will bring in you a confidence on Unix.

Test your self

Go through the previous lession once again and try to see on Unix machine, Try to play with 'ls -l' command and watch the access and permission's.

VI editor

Vi editor is basically used to edit a file.There are many options available in UNIX to edit into file.

Cmd

Meaning

[:set showmode]

Show in insert mode.

[:set ic]

case insensitive search

[:set noic]

Opposite to above

[:set number]

number on

[:set nonumber]

number off

[set all]

Setting list options

[set ai]

Autoindent on

[set noai]

Autoindent OFF

[:set autoprint]

Displaying line after exe. substitute command.

[:set window=40]

limiting window line to 40

[:set scroll=11]

limiting lines scrolled.

emacs editor

This is also a powerful editor available in the UNIX. It is manually installed and check whether it is available in the current UNIX flavor. Emacs supports many languages in the editing of text including many alphabets, scripts, writing systems, and cultural conventions. Emacs also provides spell-checking by calling ispell as external programs.

The following commands for emacs are as follow

Cmd

Meaning

[:tlhaas:~ tlhaas$ emacs]

check emacs installation.

[:tlhaas:~ tlhaas$ emacs filename]

create a new emacs file

[:ctrl-x ctrl-s ]

Save file as emacs type

[:ctrl-c ctrl-x]

Quit

[:set all]

Settings list options

[set noai]

Autoindent OFF

[:set wrapmargin=2]

Inserting line of set margin with 2 as input mode

[:set autoprint]

Displaying line after exe. substitute command.

[:set window=40]

limiting window line to 40

[:set scroll=11]

limiting lines scrolled.

SSH

SSH is a connection protocol that connect remotely between a client and a server's shell. SSH replaced to Telnet, because SSH follow security while sending sensitive information like passwords over the Internet. SSH a program kind is used for connecting to a web server, as it allow for SFTP (secure file transfer protocol) to upload a client's web files to their server. SSH terminal is a operating system independent, It is also available to microsoft xp-7 operating system. It doesn't look for UNIX to use SSH, it is really cool concept if you want to connect remotely to a UNIX system using SSH. However, SSH programs are meant to operate across many operating systems as well.The SSH that I currently use is Putty, but there are others out there to consider like OpenSSH

Test 1

Coming Soon !!!!!! :)

Last modified: 20 April 2011 12:46:28 PM

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