22 Keyboards & Command Line Interfaces

22 命令行界面

Hi, I'm Carrie Anne, and welcome to CrashCourse Computer Science!

嗨，我是 Carrie Anne，欢迎收看计算机科学速成课！

We've talked a lot about inputs and outputs in this series,

我们之前讨论过 输入输出，

but they've mostly been between different parts of a computer

但都是计算机组件互相输入输出

like outputting data from RAM or inputting instructions to a CPU.

比如 RAM 输出数据，或输指令进 CPU

We haven't discussed much about inputs coming from humans.

我们还没讲 来自人类的输入

We also haven't learned how people get information out of a computer,

也没讲怎么从电脑中拿出信息，

other than by printing or punching it onto paper.

除了用打孔纸卡

Of course, there's a wide variety of input and output devices that

当然，有很多种 "输入输出设备" ，

allow us users to communicate with computers.

让我们和计算机交互

They provide an interface between human and computer.

它们在人类和机器间提供了界面

And today, there's a whole field of study called Human-Computer Interaction.

如今有整个学科专门研究这个，叫 "人机交互"

These interfaces are so fundamental to the user experience

界面对用户体验非常重要，

that they're the focus of the next few episodes.

所以是我们接下来几集的重点

As we discussed at the very beginning of the series,

在系列开头的几集，我们提过

the earliest mechanical and electro-mechanical computing devices

早期机械计算设备，

used physical controls for inputs and outputs, like gears, knobs and switches,

用齿轮，旋钮和开关等机械结构来输入输出

and this was pretty much the extent of the human interface.

这些就是交互界面

Even the first electronic computers, like Colossus and ENIAC,

甚至早期电子计算机 比如 Colossus 和 ENIAC

were configured using huge panels of mechanical controls and patch wires.

也是用一大堆机械面板和线 来操作

It could take weeks to enter in a single program, let alone run it,

输入一个程序可能要几星期，还没提运行时间.

and to get data out after running a program, results were most often printed to paper.

运行完毕后想拿出数据，一般是打印到纸上

Paper printers were so useful

打印机超有用

that even Babbage designed one for his Difference Engine,

甚至 查尔斯·巴贝奇 都给差分机专门设计了一个

and that was in the 1820s!

那可是 1820 年代！

However, by the 1950s, mechanical inputs were rendered obsolete

然而，到 1950 年代，机械输入完全消失

by programs and data stored entirely on mediums like punch cards and magnetic tape.

因为出现了打孔纸卡和磁带

Paper printouts were still used for the final output,

但输出仍然是打印到纸上

and huge banks of indicator lights were developed

还有大量指示灯，

to provide real time feedback while the program was in progress.

在运行中提供实时反馈

It's important to recognize that computer input of this era was

那个时代的特点是

designed to be as simple and robust as possible for computers.

尽可能迁就机器，

Ease and understanding for users was a secondary concern.

对人类好不好用是其次

Punch tape is a great example

打孔纸带就是个好例子

this was explicitly designed to be easy for computers to read.

就是为了方便计算机读取

The continuous nature of tape made it easy to handle mechanically,

纸带是连续的，方便机器处理

and the holes could be reliably detected with a mechanical or optical system,

纸孔可以方便地 用机械或光学手段识别

which encoded instructions and data.

纸孔可以编码程序和数据

But of course, humans don't think in terms of little punched holes on strips of paper.

当然， 人类不是以纸孔方式思考的.

So, the burden was on programmers.

所以负担放到了程序员身上

They had to spend the extra time and effort to convert their ideas and programs

他们要花额外时间和精力，

into a language and a format that was easy for computers of the era to understand

转成计算机能理解的格式

often with the help of additional staff and auxiliary devices.

一般需要额外人员和设备帮忙

It's also important to note that early computers, basically pre-1950,

要注意的是，基本上 1950 年前的早期计算机，

had an extremely simple notion of human input.

输入的概念很原始

Yes, humans input programs and data into computers,

是的，的确是人类负责输入程序和数据，

but these machines generally didn't respond interactively to humans.

但计算机不会交互式回应

Once a program was started, it typically ran until it was finished.

程序开始运行后会一直运行 直到结束

That's because these machines were way too expensive to be

因为机器太贵了，

waiting around for humans to type a command or enter data.

不能等人类慢慢敲命令和给数据

Any input needed for a computation was fed in at the same time as the program.

要同时放入程序和数据

This started to change in the late 1950s.

这在 1950 年代晚期开始发生变化

On one hand, smaller-scale computers started to become cheap enough

一方面，小型计算机变得足够便宜

that it was feasible to have a human-in-the loop;

让人类来回和计算机交互 变得可以接受

that is, a back and forth between human and computer.

交互式就是人和计算机之间来回沟通

And on the other hand,

而另一方面

big fancy computers became fast and sophisticated enough to support many programs and users at once,

大型计算机变得更快，能同时支持多个程序和多个用户

what were called multitasking and time-sharing systems .

这叫"多任务"和"分时系统"

But these computers needed a way to get input from users.

但交互式操作时，计算机需要某种方法来获得用户输入

For this, computers borrowed the ubiquitous data entry mechanism of the era: keyboards.

所以借用了当时已经存在的数据录入机制：键盘

At this point, typing machines had already been in use for a few centuries,

当时，打字机已经存在几个世纪了

but it was Christopher Latham Sholes, who invented the modern typewriter in 1868.

但现代打字机是 ，克里斯托弗·莱瑟姆·肖尔斯 在 1868 年发明的

It took until 1874 to refine the design and manufacture it,

虽然到 1874 年才完成设计和制造

but it went on to be a commercial success.

但之后取得了商业成功

Sholes' typewriter adopted an unusual keyboard layout that you know well QWERTY

肖尔斯 的打字机用了不寻常的布局，QWERTY

named for the top-left row of letter keys.

名字来自键盘左上角按键

There has been a lot of speculation as to why this design was used.

为什么这么设计 有很多猜测

The most prevalent theory is that it put common letter pairings in English far apart

最流行的理论是 这样设计是为了，

to reduce the likelihood of typebars jamming when entered in sequence.

把常见字母放得远一些，避免按键卡住

It's a convenient explanation, but it's also probably false,

这个解释虽然省事，但可能是错的，

or at least not the full story.

或至少不够全面

In fact, QWERTY puts many common letter pairs together,

事实上，QWERTY 把很多常见字母放在了一起，

like "TH" and "ER".

比如 TH 和 ER

And we know that Sholes and his team went through many iterations

我们知道 肖尔斯和他的团队设计了很多版，

before arriving at this iconic arrangement.

才进化到这个布局

Regardless of the reason, the commercial success of Sholes' typewriter meant

总之，肖尔斯 的打字机取得了成功，

the competitor companies that soon followed duplicated his design.

所以其它公司很快开始抄他的设计

Many alternative keyboard layouts have been proposed over the last century,

过去一个世纪有不少新的键盘布局被发明，

claiming various benefits.

宣称各种好处

But, once people had invested the time to learn QWERTY,

但人们已经熟悉了 QWERTY 布局，

they just didn't want to learn something new.

根本不想学新布局

This is what economists would call a switching barrier or switching cost.

这是经济学家所说的 转换成本

And it's for this very basic human reason

所以现在都快1个半世纪了，我们还在用 QWERTY 键盘布局

that we still use QWERTY keyboards almost a century and a half later!

所以现在都快1个半世纪了，我们还在用 QWERTY 键盘布局

I should mention that QWERTY isn't universal.

我应该提一下，QWERTY 不是通用的

There are many international variants,

有很多变体，

like the French AZERTY layout,

比如法国 AZERTY 布局

or the QWERTZ layout common in central Europe.

以及中欧常见的 QWERTZ 布局

Interestingly, Sholes didn't envision that typing would ever be faster than handwriting,

有趣的是，肖尔斯 根本没想到打字会比手写快

which is around 20 words per minute.

手写速度大约是每分钟 20 个

Typewriters were introduced chiefly for legibility and standardization of documents, not speed.

打字机主要为了易读性和标准化，而不是速度

However, as they became standard equipment in offices, the desire for speedy typing grew,

然而随着打字机成为办公室标配，对快速打字的渴望越来越大

and there were two big advances that unlocked typing's true potential.

有两个重大进步 解放了打字的潜力

Around 1880, Elizabeth Longley, a teacher at the Cincinnati Shorthand and Type-Writer Institute,

1880年左右，辛辛那提速记学院，一名叫 伊丽莎白·朗利 的老师

started to promote ten-finger typing.

开始推广 十指打字

This required much less finger movement than hunt-and-peck,

比一个手指打字要移动的距离短得多，

so it offered enhanced typing speeds.

所以速度更快

Then, a few years later, Frank Edward McGurrin, a federal court clerk in Salt Lake City,

几年后，弗兰克·爱德华·麦克格林，盐湖城的一位联邦法庭书记

taught himself to touch-type; as in, he didn't need to look at the keys while typing.

学会了盲打，打字时不用看键盘

In 1888, McGurrin won a highly publicized typing-speed contest,

1888年，麦格高林 赢了备受关注的打字速度比赛

after which ten-finger, touch-typing began to catch on.

之后"十指盲打"开始流行

Professional typists were soon able to achieve speeds upwards of 100 words per minute,

专业打字员 每分钟 100 字以上

much faster than handwriting!

比手写快多了！

And nice and neat too!

而且清晰又整洁！

So, humans are pretty good with typewriters,

虽然人类擅长用打字机

but we can't just plunk down a typewriter in front of a computer and have it type

但我们没法把打字机塞到计算机面前，让它打字

they have no fingers!

计算机又没有手指

Instead, early computers adapted a special type of typewriter that was used for telegraphs,

所以早期计算机用了一种特殊打字机，是专门用来发电报的，

called a teletype machine.

叫 电传打字机

These were electromechanically-augmented typewriters

这些打字机是强化过的，

that can send and receive text over telegraph lines.

可以用电报线发送和接收文本

Pressing a letter on one teletype keyboard would cause a signal to be sent,

按一个字母，信号会通过电报线，

over telegraph wires, to a teletype machine on the other end,

发到另一端

which would then electromechanically type that letter.

另一端的电传打字机会打出来

This allowed two humans to type to one another over long distances.

使得两人可以长距离沟通

basically a steampunk version of a chat room.

基本是个蒸汽朋克版聊天室

Since these teletype machines already had an electronic interface,

因为电传打字机有电子接口，

they were easily adapted for computer use,

稍作修改就能用于计算机

and teletype computer interfaces were common in the 1960s and 70s.

电传交互界面在 1960~1970 很常见

Interaction was pretty straightforward.

用起来很简单

Users would type a command, hit enter, and then the computer would type back.

输入一个命令，按回车，然后计算机会输回来

This text "conversation" between a user and a computer went back and forth.

用户和计算机来回"对话"

These were called command line interfaces,

这叫"命令行界面"

and they remained the most prevalent form of human-computer interaction

它是最主要的人机交互方式，

up until around the 1980s.

一直到 1980 年代

Command Line interaction on a teletype machine looks something like this.

用电传打字机的命令行交互 类似这样：

A user can type any number of possible commands.

用户可以输入各种命令

Let's check out a few,

我们来看几个命令，

beginning with seeing all of the files in the current directory we're in.

先看当前目录有什么文件

For this, we would type the command, "ls", which is short for list,

输入命令 ls，名字来自 list 的缩写

and the computer replies with a list of the files in our current directory.

然后计算机会列出 当前目录里的所有文件

If we want to see what's in our "secretStarTrekDiscoveryCast.txt.txt file",

如果想看 secretStarTrekDiscoveryCast.txt 有什么

we use yet another command to display the contents.

要用另一个命令 显示文件内容

In unix, we can call "cat" short for concatenate.

unix 用 cat 命令显示文件内容，cat 是连接(concatenate)的缩写

We need to specify which file to display, so we include that after the command, called an argument.

然后指定文件名，指定的方法是写在 cat 命令后面，传给命令的值叫 参数

If you're connected to a network with other users,

如果同一个网络里有其他人

you can use a primitive version of a Find My Friends app

你可以用 finger 命令找朋友，

to get more info on them with the command "finger".

就像是个很原始的"找朋友" App

Electromechanical teletype machines

电传打字机

were the primary computing interface for most users up until around the 1970s.

直到1970年代左右都是主流交互方式

Although computer screens first emerged in the 1950s,

尽管屏幕最早出现在 1950 年代，

and were used for graphics they were too expensive and low resolution for everyday use.

但对日常使用太贵 而且分辨率低

However, mass production of televisions for the consumer market, and general improvements

然而因为针对普通消费者的电视机开始量产，同时处理器与内存也在发展

in processors and memory, meant that by 1970, it was economically viable

到1970年代，屏幕代替电传打字机

to replace electromechanical teletype machines with screen-based equivalents.

变得可行

But rather than build a whole new standard to interface computers with these screens,

但与其为屏幕 专门做全新的标准

engineers simply recycled the existing text-only, teletype protocol.

工程师直接用现有的 电传打字机协议

These machines used a screen, which simulated endless paper.

屏幕就像无限长度的纸，

It was text in and text out, nothing more.

除了输入和输出字，没有其它东西

The protocol was identical, so computers couldn't even tell if it was paper or a screen.

协议是一样的，所以计算机分不出是纸还是屏幕

These virtual teletype or glass teletype machines became known as terminals .

这些"虚拟电传打字机"或"玻璃电传打字机"，叫 终端

By 1971, it was estimated, in the United States,

到1971年，美国大约有

there was something on the order of 70,000 electro-mechanical teletype machines

7 万台电传打字机，

and 70,000 screen-based terminals in use.

以及 7 万个终端

Screens were so much better, faster and more flexible, though.

屏幕又好又快又灵活

Like, you could delete a mistake and it would disappear.

如果删一个错别字 会立刻消失

So, by the end of the 1970s, screens were standard.

所以到 1970 年代末 屏幕成了标配

You might think that command line interfaces are way too primitive to do anything interesting.

你也许会想，命令行界面太原始了，做不了什么有意思的事

But even when the only interaction was through text, programmers found a way to make it fun.

即便只有文字，程序员也找到了一些方法，让它变得有趣一些

Early interactive, text-based computer games include famous titles like Zork,

早期的著名交互式文字游戏 Zork

created in 1977.

出现于 1977 年

Players of these sorts of early games were expected to engage their limitless imaginations

早期游戏玩家需要丰富的想象力

as they visualized the fictional world around them, like what terrifying monster confronted them

想像自己身在虚构世界，比如"四周漆黑一片

when it was pitch black and you were likely to be eaten by a grue.

附近可能有怪物会吃掉你"

Let's go back to our command line, now on a fancy screen-based terminal, and play!

我们用命令行玩玩看

Just like before, we can see what's in our current directory with the "ls" command.

就像之前，我们可以用 ls 命令，看当前目录有什么

Then, let's go into our games directory by using the "cd" command, for " change directory ".

然后用 cd 命令，进入游戏文件夹，cd 的意思是 "改变文件夹"

Now, we can use our "ls" command again to see what games are installed on our computer.

再用 ls 看有哪些游戏

Sweet, we have Adventure!

超棒！我们有"冒险旅程"！(adventure)

All we have to do to run this program is type its name.

想运行这个程序，只需要输入它的名字

Until this application halts, or we quit it, it takes over the command line.

在程序自行停止或我们主动退出前，它会接管命令行

What you're seeing here is actual interaction from "Colossal Cave Adventure",

你现在看到的，是"巨大洞穴冒险"这款游戏的真实输出

first developed by Will Crowther in 1976.

由 Will Crowther 在 1976 年开发

In the game, players can type in oneor two-word commands to move around,

游戏中，玩家可以输入1个词或2个词的命令，来移动人物，

interact with objects, pickup items and so on.

和其他东西交互，捡物品等

The program acts as the narrator, describing locations, possible actions,

然后游戏会像旁白一样，输出你的当前位置，告诉你能做什么动作，

and the results of those actions.

以及你的动作造成的结果

Certain ones resulted in death!

有些动作会导致死亡！

The original version only had 66 locations to explore,

原始版本只有 66 个地方可供探索

but it's widely considered to be the first example of interactive fiction.

但它被广泛认为是最早的互动式小说

These text adventure games later became multiplayer, called MUDs or Multi-User Dungeons.

游戏后来从纯文字进化成多人游戏，简称 MUD，或多人地牢游戏

And they're the great-forbearers of the awesome graphical MMORPG's

是如今 MMORPG 的前辈，

(massive, multiplayer online role playing games) we enjoy today.

（大型多人在线角色扮演游戏）

And if you want to know more about the history of these and other games

如果你想了解游戏史，我们有游戏速成课 ，

we've got a whole series on it hosted by Andre Meadows!

主持人 Andre Meadows

Command line interfaces, while simple, are very powerful.

命令行界面虽然简单 但十分强大

Computer programming is still very much a written task, and as such,

编程大部分依然是打字活，

command lines are a natural interface.

所以用命令行比较自然

For this reason, even today, most programmers use

因此，即使是现在 ，

command line interfaces as part of their work.

大多数程序员工作中依然用命令行界面

And they're also the most common way to access computers that are far away,

而且用命令行访问远程计算机 是最常见的方式，

like a server in a different country.

比如服务器在另一个国家

If you're running Windows, macOS or Linux,

如果你用 Windows， macOS， Linux

your computer has a command line interface one you may have never used.

你的计算机有命令行界面，但你可能从来没用过

Check it out by typing "cmd" in your Windows search bar,

你可以在 Windows 搜索栏中输入 cmd

or search for Terminal on Mac.

或在 Mac 上搜 Terminal

Then install a copy of Zork and play on!

然后你可以装 Zork 玩！

So, you can see how these early advancements still have an impact on computing today.

现在你知道了，早期计算机的发展是如何影响到现在的.

Just imagine if your phone didn't have a good ol' fashioned QWERTY keyboard.

想想要是手机没有 QWERTY 键盘，在 Instagram 给图片配标题可就麻烦了

It could take forever to type your Instagram captions.

想想要是手机没有 QWERTY 键盘，在 Instagram 给图片配标题可就麻烦了

But, there's still something missing from our discussion.

但我们还有一个重要话题没讲

All the sweet sweet graphics!

美妙的图形界面！

That's our topic for next week.

这是下周的主题

See you soon.

下周见