linuxcaseinor

㈠ 找英文资料呀！高分，多多益善！！

这是一篇有关电脑发明及介绍的短文，希望你满意！
You’ve probably known about computers your whole life. But computers have not really been around for very long. Computers started to become popular with big companies in the 1960s. Computers didn’t become widespread in homes and schools until the 1980s.

HOW DO PEOPLE USE COMPUTERS?

People use computers in many ways. Stores use computers to keep track of procts and check you out at the cash register. Banks use computers to send money all over the world.

Computers help teachers keep track of lessons and grades. They help students do research and learn. Computers let you hook up to networks (many computers hooked together). They let you hook up to a worldwide network called the Internet.

Scientists use computers to solve research problems. Engineers use computers to make cars, trucks, and airplanes. Architects use computers to design houses and other buildings. The police use computers to track down criminals. The military uses computers to make and read coded messages.

Computers are not just desktops and laptops. Computers are everywhere around your home. There are tiny computers inside microwave ovens, television sets, and videocassette recorders (VCRs) or digital video disc (DVD) players. There are even tiny computers in cars to help them run better.

HARDWARE AND SOFTWARE

Computers need hardware and software in order to work. Your desktop or laptop and all the parts inside are called hardware. The central processing unit (CPU) makes the computer work. The keyboard, mouse, printer, and monitor are also pieces of computer hardware.

Memory chips are hardware that stores information and instructions. Information also gets stored on the hard disk drive.

The programs that run the computer are called software. The computer operating system is software that tells the computer how to run. Applications or programs are software that do certain tasks. Word-processing programs, for example, let you write school reports and letters.

HOW CAN COMPUTERS DO SO MUCH?

One reason that computers can do so much is that they have a special language that tells them what to do. Computer language has only two letters: zeros and ones. Computers can read these ones and zeros extremely quickly.

Each zero or one is called a bit. Eight zeros and ones together are called a byte. Bits and bytes get stored in computer memory chips. Every year, computer engineers make chips that can hold more bytes. The chips can hold more information. Programmers can write applications that can do more things.

WHO INVENTED THE COMPUTER?

Many inventions have contributed to the development of modern computers. French mathematician Blaise Pascal and other inventors in the 1600s began making machines that could add and subtract numbers. Wheels, levers, and other moving parts made these machines work. In the 1800s, British mathematicians Charles Babbage and Augusta Ada Byron, countess of Lovelace, worked on plans for machines that could store information on cards with holes punched in them.

American inventor Herman Hollerith made a machine that automatically totaled population figures for the 1890 United States census. His company joined with other companies to become International Business Machines (IBM) in 1924. Other inventors built better computers. But none of these early computers were digital—that is, none used the digits zero and one.

The first digital computer, called ENIAC, was built in the 1940s. It was huge. It was as big as a house. It had more than 18,000 glass tubes inside and weighed more than five elephants.

The first computer used by business was called UNIVAC. Big computers like ENIAC and UNIVAC were called mainframes. The desktop or laptop computer that you use today is much more powerful than those big machines.

In the 1940s, scientists at Bell Telephone Laboratories invented a tiny electric switch called the transistor. In the 1960s, scientists and engineers invented integrated circuits or computer chips. Computer chips cram millions of transistors into a space the size of your little fingernail. Computer chips allowed computers to be smaller.

Personal computers (PCs) were invented in the 1970s. Most PCs are meant to be used by only one person at a time. They are small enough to fit on a desk. The Altair 8800 was the first PC. Apple Computer made its first PC in 1977. IBM made its first PC in 1981.

WHO INVENTED COMPUTER PROGRAMS?

Computer programs are sets of instructions that tell a computer what to do. Many people worked on early computer programs. The first programs were very hard to write and understand. They were extremely long strings of zeros and ones.

American naval officer and mathematician Grace Murray Hopper in 1952 wrote the first program that turned English computer instructions into the strings of ones and zeros that make computers work. These programs are called compilers. In 1957, she helped develop the first programming language that companies could buy and use. It was called FLOW-MATIC. Hopper was also the first to use the word bug to mean a problem with a computer. She found a moth trapped in one of the computers she worked with. She taped the moth into her notebook and wrote, “First actual case of a bug being found.”

LATER DEVELOPMENTS

As computers have become more powerful and widespread, operating systems have become extremely complex. Few people can use a computer without one. Scientists at AT&T developed an operating system called UNIX in 1969. UNIX and related operating systems such as linux are popular at universities and among computer professionals. In 1975, Bill Gates and his friend Paul Allen wrote a program for the Altair 8800 and founded the Microsoft Corporation. Microsoft later developed the DOS and Windows operating systems used on many home and office PCs.

Computers keep getting smaller and more powerful. Personal computers that fit on a desktop today are more powerful than early “supercomputers” that filled entire rooms. Cell phones and watches contain tiny computers that can store information such as telephone numbers, addresses, and appointments. These devices allow you to surf the Web and play games. Many computer experts think that computers have only begun to make their mark on history.

㈡ linux中&&和||什么意思

在某些情况下，很多指令我想要一次输入去执行，而不想要分次去执行时，就要用到 && || 了。
cmd 1 && cmd2
1,若cmd1执行完毕之后且正确执行（$?=0），则开始执行cmd2。
2，若cmd2执行完毕之后且执行错误（$? not equal 0）,则cmd2不执行。

cmd1 || cmd2
1,若cmd1执行完毕之后且正确执行，则不执行cmd2.
2,若cmd2执行完毕之后错误执行，则开始执行cmd2

㈢ linux命令 --lines=10是什么意思

这种写法应该是某个命令的参数，不像是命令本身。

㈣ 怎么看linux 命令格式,哪些是必选项,哪些是可选项

Linux命令与DOS原理一样，只是命令不一样而已。

㈤ linux ln -s 用ln -s 链接 根目录到 /home/good怎么做啊。

创建软连接，命令如下：

ln -s / /home/good/linkname

ln的链接分软链接和硬链接两种：

1、软链接就是：“ln –s 源文件 目标文件”，只会在选定的位置上生成一个文件的镜像，不会占用磁盘空间，类似与windows的快捷方式。

2、硬链接ln源文件目标文件，没有参数-s， 会在选定的位置上生成一个和源文件大小相同的文件，无论是软链接还是硬链接，文件都保持同步变化。

(5)linuxcaseinor扩展阅读

软链接又叫符号链接，这个文件包含了另一个文件的路径名。可以是任意文件或目录，可以链接不同文件系统的文件。

链接文件甚至可以链接不存在的文件，这就产生一般称之为”断链”的现象，链接文件甚至可以循环链接自己。类似于编程语言中的递归。

软链接文件只是其源文件的一个标记，当删除了源文件后，链接文件不能独立存在，虽然仍保留文件名，但却不能查看软链接文件的内容了。

用ln -s 命令可以生成一个软连接，如下:

[root@linux236 test]# ln -s source_file softlink_file

在对符号文件进行读或写操作的时候，系统会自动把该操作转换为对源文件的操作，但删除链接文件时，系统仅仅删除链接文件，而不删除源文件本身。

删除硬/软链接用rm softlink_file

或者unlink softlink_file

㈥ Linux与Solaris的区别

Linux与Solaris之间的主要区别

1、Linux的稳定性较差。与Linux相比，Solaris具有更稳定的稳定性。

2、Linux有一个基本的调度。Solaris具有广泛的调度以及在需要时使用和配置的能力。

3、Linux具有标准的输入输出能力。Solaris具有广泛的多路径COMSTAR支持。

4、Linux有一个旧的服务机制，如SVR4，它是基于文本的，不允许任何依赖和服务配置无法

还原。Solaris具有一种新的服务机制，具有SMF等强大功能，基于x ml配置，允许依赖项和配

置可以在需要时还原。

5、Linux与平台无关。虽然Solaris可用于不同的体系结构，但它不适用于某些平台。

6、Linux提供了良好的安全性和性能。Solaris提供了严格的安全功能，为性能提供了极大的安

全保障。

7、Linux具有良好的管理能力。Solaris具有出色的管理员能力，可以轻松安装和管理系统。

8、Linux支持主要由Red Hat提供。Oracle提供的Solaris支持（在获得Sun Microsystem之

后）。

㈦ 查看linux 操作系统为多少位.

1. 执行‘uname -a’ 命令

㈧ 熟悉的linux shell命令or命令+参数，并指明它们能够完成什么操作

shell就是字面意思：外壳，你操作linux是通过shell，shell就是linux的外壳。是个统称。
linux脚本很多，最长用的是bash（bash shell），shell的一种，就像linux是操作系统的一种。
命令都一样啊，就是命令，什么是高端命令呢？不常用的？用法复杂的？
就像你说的，不同情况用不同命令，没有高端不高端的。
《鸟哥的Linux私房菜》公认入门宝典

㈨ 在linux下shell脚本中if中用到or怎么写

linux下shell脚本的逻辑的or用运算符 || 表示，if中用到or的写法实例如下：

a=10

b=20

if[[$a-lt 50||$b-gt 50]]

then

echo"返回 true"

else

echo"返回 false"

fi

其中$a-lt100表示a<50 为真；$b-gt 50 表示b>50为假；真 or 假为真。

所以输出结果为：返回 true

(9)linuxcaseinor扩展阅读

1、shell中流程控制if基本语法介绍：

if condition

then

command1

command2 ...

commandN

fi

2、shell中的另一个逻辑运算符and （&&）用法实例介绍：

a=10

b=20

if[[$a-lt100&&$b-gt100]]

then

echo"返回 true"

else

echo"返回 false"

fi

输出结果为：返回 false