Unix

The Linux kernel offers the user a host of operating systems that are free and can be copied and distributed as much as you like. Known genetically as 'Open Source' and, often small group or community maintained, you can freely try out a variety of distributions. All this without having to register to get a licence as you would need to do if using propriety MS Windows.

Shell scripts are interpreted files that contain commands and logic sequences to do things. They are similar to programs in that they contain logic and sequencing, and call other programs to accomplish tasks.

You use shell scripts to automate tasks in Unix, run tasks periodically, create repeatable tasks, etc.

#include<stdio.h>

void main()

{

int num, sum=0, i;

printf("Enter ten numbers: \n");

for(i=0;i<10;i++)

{

scanf("%d",&num);

sum += num;

}

printf("\n The sum of the numbers is %d",sum);

getchar();

}

The kernel The kernel 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. 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 AS/400 is a specific piece of hardware manufactured by IBM corporation. It runs its own operating system. Unix is the designation for an Operating System and runs on multiple hardware.

To my knowledge the AS/400 does not run any version of Unix.

echo "Enter a number: "

read num

i=2

res=1

if [ $num -ge 2 ]

then

while [ $i -le $num ]

do

res=`expr $res \* $i`

i=`expr $i + 1`

done

fi

echo "Factorial of $num = $res" v

Unix is unique

No: Linux is a general purpose operating system, and it has a windows system as well.

Yes: Linux looks like a window operating system to the uninitiated.

This is too general a question to be able to answer in a wiki format. Please be more specific.

When a user logs in to a Unix system, the current working directory normally starts at the directory/file

The time command is used to time a command and not display the actual time. To display the time and date, the date command must be used.

the unix phylosophy is "do a single job correctly" . due to this the authors / creatorscreated unix commands simpler. to do complex tasks the simpler commands are combined. for example

head command is used to displasy the top ten or required number of lines from a file "file"

tail commandis used to displasy the lastten or required number of lines from a file "file"

but if i require to lines from 3rd line to 10th line i does not have the command to do this

i combine head & tail commands

head -10 file | tail -7

by

rami reddy

There are very few similarities beyond some convergent features of their respective user interfaces. Their internal architecture is very different, differing from kernel models to shell integration to executable formats. A comprehensive list of similarities is neither possible nor useful, because it would consist mostly of obvious statements like "They are both operating systems" or "They both have graphical user interfaces, "They both include web browsers" and the like.

Richie and Thompson, along with Kernighan and others.

In computer operating systems, demand paging is an application of virtual memory. In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is made to access it (i.e., if a page fault occurs). It follows that a process begins execution with none of its pages in physical memory, and many page faults will occur until most of a process's working set of pages is located in physical memory. This is an example of lazy loading techniques.

The 'uptime' command will tell you exactly how many users are on the system. There are other variations of this, including counting the number of words from the 'users' command, etc., but this is the easiest.

Usually nothing. The file extension (the .jpeg, .exe, .png, .mov, etc.) tells what kind of file it is. Certain programs deal with certain extensions, like word with .doc, .rtf, and .txt. Paint and photoshop deal with .jpeg, .png, .gif, and .bmp. Powerpoint deals with .ppt, and so on. Hope this helps!

Unix is a classification of operating systems that conform to a certain specification, based on that of the original Unix operating system created by AT&T. Systems certified as Unix can differ drastically, but must meet at least certain common elements.

Solaris is an implementation of Unix created by Sun Microsystems.

Linux is a family of operating systems based on a kernel written by Linus Torvalds. It shares some design goals and similarities with Unix, but has several advanced features and is not completely compatible with Unix. Legally, for a system to be described as "Unix", it must undergo a certification process. No Linux distribution has ever undergone this (very expensive) certification process to make it compliant with Unix standards.

Solaris uses older, POSIX-compliant utilities. Linux typically uses GNU utilities, which are generally compatible, but have different command switches and more features. This is beginning to change with the OpenSolaris project, which incorporates many GNU utilities.

Solaris and Linux both have features that the other lacks, and are not found in other Unix implementations either. These include DTRace and the ZFS file system (in Solaris) and dynamically loadable kernel modules and epoll (in Linux).

Unix was created almost entirely in C. It consists of a main component (called the kernal) and a flotilla of small utilities. Most of these utilities were written in C. Unix distributions usually come with a C compiler so you can create or modify the environment yourself.

However, C is not your only choice. Modern versions of Unix still contain a C compiler, but they often have dozens of other languages available. Most versions of Linux come with a C++ compiler (which is different than C) as well as compilers and interpreters for Java, Perl, and Python. You can generally install hundreds of other languages.

The language you use depends on the type of problem you are solving. Generally you'll use C for basic low-level work, but you'll often pick a higher-level language to solve 'real-world' problems. For example, if you're doing server-side web development, you'll usually use PHP.

AWK is a programming language developed in 1977 by Alfred Aho, Peter Weinberger, and Brian Kernighan. It is was developed as a text-processing language - it has simple syntax to match lines of patterns, separate out the fields, and operate on them.

perl -e 'sub f { my $fu = shift; return 1 if $fu == 1; return f($fu - 1) * $fu; } print f(5), "\n";'

just paste that in to a command prompt, change the print f(5) to print f(6) or whatever you want.

Just like Windows or Apple's mac OS, Linux is an operating system. An operating system is the collection of software that manages the different devices and applications in a computer. For example, some of the software is responsible for shutting down and starting the computer, and some software provides functions such as interacting with devices such as keyboards and mice. Learning to use a Linux system is an excellent opportunity to become familiar with the command line, the most definitive way to communicate with your computer. Plus, as you experiment with different projects, you'll learn about repositories, package management, file permissions, user management, and more.

The full name of CCNA is Cisco Certified Network Associate, and Cisco (Cisco) is the world's largest network equipment company. According to the IT certification examination resource network, CCNA is the primary technical certificate in the Cisco certification system.

First of all, CCNA is a manufacturer's certification, which is internationally accepted. It is an English-only exam that requires a high school English foundation.

Shell scripts are not compiled; they are interpreted (and therefore do not need to be compiled). Just type in the name of the shell script and any parameters it needs to execute.