document/TranslateProject
2
0
Fork 0
mirror of https://github.com/LCTT/TranslateProject.git synced 2025-01-25 23:11:02 +08:00
Code Issues Packages Projects Releases Wiki Activity

[translated] 20140729 Don't Fear The Command Line.md

Browse Source
This commit is contained in:
Frank Zhang 2014-11-04 11:12:30 +08:00
parent eec339e3e2
commit 5a6ee8c859
2 changed files with 135 additions and 138 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

138
sources/talk/20140729 Don't Fear The Command Line.md
View File

@ -1,138 +0,0 @@
zpl1025
Don't Fear The Command Line
================================================================================
![](http://a4.files.readwrite.com/image/upload/c_fill,h_900,q_70,w_1600/MTE5NTU2MzIyNTM0NTg5OTYz.jpg)
> Embrace your computer's most useful tool.
You've probably seen it in movies, even if you haven't ever called it up on your own computer: a blank screen with a simple text prompt and a cursor, just waiting for you to enter the appropriate arcane commands to do your bidding.
This is the command line. It's a text-based interface that predates the far more familiar windows, icons and tiles of today's major computer operating systems, from Windows to Mac OS X to Linux.
The command line is an extremely powerful tool for accessing basic functions of your computer. For most people, it's also a confusing, complicated and seemingly irrelevant distraction. It doesn't have to be.
### Computers Under Your Command ###
Typing text instructions and hitting Return to get a computer to do something sounds like a major step back compared to the swipe-and-tap touch-sensitive interfaces of mobile devices. Even a toddler can use an iPad, right? Yet the command line can save you time and aggravation, if you know when to use it.
If you're serious about learning to code—or just understanding computer technology—you absolutely need to get to know your command line.
Diving into the command line will teach you a lot about how your computer works and organizes information. You might find that some tasks you perform every day with a mouse are actually faster when you type a command or two instead.
Most important, you’ll be better prepared to learn [languages like Python][1] and [programs like Git][2] that require some command-line setup. By getting familiar with the command line, you’ll break down barriers that may have kept you from learning to program in the past.
So here's a quick, basic guide to getting around on the command line. It's focused on Mac OS X's Unix-based environment, simply because that's what I'm familiar with. Linux users probably know the command line well already, although newcomers might also find these tips useful. If you're running a Chromebook, Google has some helpful instructions for getting to its [version of the command line][3], which is similar to Mac and Linux systems. Windows users, unfortunately, are stuck with a command language derived from MS-DOS that just barely overlaps with Unix, so this guide isn't going to be much use to you; you might check out [this dosprompt.info tutorial][4].
### How To Find Your Way Around ###
The very first thing you’ll need to do is figure out how to access the command line, which is typically done through a program called a "shell." On any Mac running OS X, you'll need to start the Terminal application. You can do this through the Finder (it's in the Utilities folder under Applications), or just click the magnifying glass in the upper right hand corner of your screen and type “terminal,” then select it from the drop-down.
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTE4MDAzNDE2ODYxMjc5NzU4.png)
You’re in, but all you see is a blank box with a space to type prompts. This is the command line! Let’s get to know this window a little bit better.
Type pwd, which stands for Print Working Directory. In computer parlance, “printing” something has nothing to do with paper. It really just means spitting it out on the screen. The command should result in the computer returning the directory you are currently working in.
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDMzMjYyNjA0.png)
And indeed, /Users/laurenorsini is my home directory. Advanced tip: You can use the tilde symbol (~) as a shortcut for your home directory—it means the same thing as /Users/yourusername. So you can reference your Downloads subdirectory, for instance, as ~/Downloads. (If you look closely at the command prompt above, you'll see a tilde there. That indicates that I'm in my home directory.)
We don’t want to muddy up our main directory with all our command-line experimenting, so let’s make a new directory with the mkdir command. This is the same as creating a new folder on your desktop operating system. Let's call it "experiments":
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMTMwODUxODU1.png)
Now we have a new directory. Using the graphic interface, we can visually verify that we actually created a new one. Sure enough, if I open the Finder and go into my home directory—here marked with a little house icon—I now see a folder named “experiments.” I made that on the command line! (The reverse works, too: You can create a folder on your desktop, and see it in the command line. They're just two different ways of looking at the same system.)
![](http://a5.files.readwrite.com/image/upload/c_fit,w_630/MTE5NTU2MzIyNTM0MzI3ODE5.png)
Now I need to change directories and enter the ~/experiments directory with the **cd** (change directory) command.
![](http://a5.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMTMxMTEzOTk5.png)
I have my command prompt on the default setting, so it automatically shows where my working directory is. But if yours looks different, here's how to make sure “experiments” is truly your working directory: type **pwd** again. It should tell you that your working directory is “experiments.”
### Getting Filed Away ###
I create and edit files on the command line every day that I code. It's faster than using the graphical user interface because I can test out my programs on the command line as soon as I finish editing them. And if I also happen to be pushing things to [GitHub][5] at the same time, well, it's even more convenient.
Now you have a new directory (also called a repository or folder) on your computer to mess around with. Let's start by creating a new file that contains only the words, "Hello World." There are a lot of ways to do this; here I'm using the echo command.
Now you have a new directory (also called a repository or folder) on your computer to mess around with. Let's start by creating a new file that contains only the words, "Hello World." There are a [lot of ways][6] to do this; here I'm using the **echo** command.
![](http://a2.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMjQxMjgwMDE1.png)
Oh no! I spelled "newfile" incorrectly. That happens. Let's fix it in two steps. First, I'll create a new file with the correct spelling...
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MjA5ODAzNzg5.png)
And then, I'll use the **mv** (move) command to replace my old, misspelled file with my new file. This always takes the form "**mv oldfile newfile**."
![](http://a1.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MjA5NzM4MjUz.png)
A note about **mv**: like many commands, it's a deceptively powerful one. When we're "moving" newfil.txt into newfile.txt, what we're actually doing is completely overwriting the first file and replacing it with the second. So the text I wrote into newfil.txt is gone forever, replaced by what I wrote into newfile.txt.
To prove that I only have one file in my directory, I can use **ls** , the list command, to get a list of all the files in this directory.
![](http://a1.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MTA3NTAyMDkz.png)
See? Just the one. And if I look inside the folder using my computer's graphical user interface, I can see the file there, too.
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDM4OTY0MjM2.png)
But it's just a blank text file. Let's put something inside it using a text editor. On the command line, I tend to use the nano editor since it's simple and it works on just about every type of computer.
This should immediately bring up a new editing screen right inside your command line window. The basic commands are all laid out for you.
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDM5NjE5NTk2.png)
Write what you want, and then exit with CTRL + X. If it asks you to save and you'd like to, type "Y."
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MTA4MDkxOTE3.png)
As you've probably guessed by now, it's possible to also see these changes by using the operating system and navigating to newfile.txt with your mouse. Here you can open and edit the file you've created in any text editor of your choice.
If you want to delete the file forever, do that with the **rm** (remove) command:
![](http://a2.files.readwrite.com/image/upload/c_fit,w_630/MTE5NTU2MzIyNTQxMzQwMTcx.png)
Keep in mind that the **rm** command is very powerful! A [common trick][7] on hacker forums is to convince a command-line newbie to type **rm -rf** / so she ends up deleting her whole computer. The "/" means the very top-level directory of your computer—and everything underneath it. NEVER type that command!
### Further Reading ###
This is just the beginning of the endless possibilities of the command line. You can use this tool to control every aspect of your computer, which is what makes it as dangerous as it is powerful. Make sure to always read up on new command-line prompts before you use them, and never blindly input a prompt that a stranger suggests to you online.
I've outlined the commands I use every day so I can code, but there are a lot more reasons to master the command line than that. If you're looking for a more thorough overview, you might want to try:
[The Command Line Crash Course][8]. A free, extended course that covers the basics of command line usage.
[A Command Line Primer For Beginners][9]. Lifehacker’s collection of helpful commands for first time users.
[Introduction to the Mac OS X Command Line][10]. Online-education site Treehouse covers the very basics in extreme detail.
Now that you've finished reading, you're better prepared for any code tutorial I've written in the past, since it's impossible to do any of them without typing in some commands. If you're ready to go, I suggest you check out ReadWrite's [Git tutorial][11], which utilizes the command line to introduce you to collaborative coding. Happy computing!
*Lead photo by [Jason Scott][12]; all other screenshots by Lauren Orsini for ReadWrite*
--------------------------------------------------------------------------------
via: http://readwrite.com/2014/07/18/command-line-tutorial-intro
作者：[Lauren Orsini][a]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
[a]:http://readwrite.com/author/lauren-orsini
[1]:http://readwrite.com/2014/07/08/what-makes-python-easy-to-learn
[2]:http://readwrite.com/2013/09/30/understanding-github-a-journey-for-beginners-part-1
[3]:http://www.chromium.org/chromium-os/poking-around-your-chrome-os-device
[4]:http://dosprompt.info/
[5]:http://www.github.com/
[6]:http://www.cyberciti.biz/faq/unix-create-file-from-terminal-window-shell-prompt/
[7]:http://www.urbandictionary.com/define.php?term=rm+-rf+%2F
[8]:http://cli.learncodethehardway.org/book/
[9]:http://lifehacker.com/5633909/who-needs-a-mouse-learn-to-use-the-command-line-for-almost-anything
[10]:http://blog.teamtreehouse.com/introduction-to-the-mac-os-x-command-line
[11]:http://readwrite.com/2013/09/30/understanding-github-a-journey-for-beginners-part-1
[12]:http://en.wikipedia.org/wiki/Computer_terminal#mediaviewer/File:DEC_VT100_terminal.jpg

135
translated/talk/20140729 Don't Fear The Command Line.md Normal file
View File

@ -0,0 +1,135 @@
不要害怕命令行
================================================================================
![](http://a4.files.readwrite.com/image/upload/c_fill,h_900,q_70,w_1600/MTE5NTU2MzIyNTM0NTg5OTYz.jpg)
> 接纳你电脑上最有用的工具。
你应该在电影中见到过，尽管从没在自己电脑上调出来：一个空白屏幕，带有一些简单文字提示和一个光标，等着你去输入几个神秘的命令，就会听你的吩咐。
这就是命令行。它是基于字符的接口，早于现在更加熟悉的主流操作系统上的窗口，图标和`瓦片 tiles`，包括Windows到Mac OS X和Linux。
命令行是一个使用你电脑基本功能的超级强大的工具。对于大多数人来说，它也是一个让人困惑的，难以理解的，看上去无关紧要的东西。不必那么夸张。
### 在你的命令控制下的电脑 ###
输入字符指令再敲下回车来让电脑做点事情，和在移动设备的触摸界面上滑动点击比较，听起来像是退了一大步。即使是刚学走路的小孩都可以用iPad，对吧？不过，如果你知道怎么用的话，命令可以节省你的时间和烦恼。
如果你很认真想学习编程-或者想理解计算机技术-你完全有必要掌握命令行。
深入到命令行里，将教会你很多关于电脑如何工作以及管理信息的。你也许会发现有些平常使用鼠标操作的功能，当改为敲一两个命令后，实际上会更快。
更重要的是，你会更容易理解[像Python那样的编程语言][1]和[像Git那样的软件][2]，需要有一点命令行基础。在熟悉了命令行以后，你就可以打破过去阻止你学习编程的障碍了。
所以在这里介绍一点关于命令行的快速，基础指导。它主要专注于Mac OS X的类Unix环境，只是因为这是我比较熟悉的。Linux用户应该已经很熟悉命令行了，不过新手也许还是会觉得这些小窍门有点用。如果你用的是Chromebook，Google已经给出了有用的指导，用来打开它自带的[命令行工具][3]，它和Mac或Linux系统有点类似。对于Windows用户，很不幸，受限于从MS-DOS衍生出的命令语言，它和Unix只有一点点交集，所以这篇指导对你没什么用；不过可以去看下[dosprompt.info网站里的资料][4]。
### 如何开始 ###
你需要做的第一件事是搞清楚如何进入命令行，通常这是通过一个叫“shell”的软件来做的。在任意一台运行OS X的Mac上，需要启动终端应用。你可以通过Finder来打开（它是在应用程序下的实用工具目录里），或者点击屏幕右上角的放大镜然后输入“terminal”，然后在下拉列表里选择。
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTE4MDAzNDE2ODYxMjc5NzU4.png)
你进来了，但是所有你看到的只是一个有输入空间的空白盒子。这就是命令行！让我们来更好地了解一下这个窗口。
输入`pwd`，它的意思是打印当前工作目录。在计算机语言里，“打印”什么和纸没一点关系。它实际上只是意味着吐点东西到屏幕上。这个命令运行的结果是让计算机返回你当前正处在的目录路径。
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDMzMjYyNjA0.png)
实际上，`/Users/laurenorsini`是我的主目录。高级提示：你可以使用波浪符(~)作为自己主目录的简写 - 它和`/Users/你的用户名`是一样的。比如，你可以像`~/Downloads`这样引用你的下载目录。（如果你仔细看前面的命令提示，你会发现那里有一个波浪符。这说明我当前正在自己的主目录下。）
我们肯定不希望我们的命令行试验把自己的主目录弄的一团糟，所以让我通过`mkdir`命令来创建一个新目录。这和在桌面操作系统里创建一个新目录是一样的。让我们把它叫做“experiments”：
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMTMwODUxODU1.png)
现在我们有一个新目录了。如果使用图形界面的话，我们可以用自己的眼睛判断我们已经创建了一个新目录。当然，如果我打开Finder然后进入我的主目录-用一个小房子图标标记的-就会看到一个叫“experiments”的目录。我通过命令行实现的！（反过来：你可以在桌面系统里建立一个文件夹，然后在命令行下去查看。这只是同一套系统的两种不同表现方式。）
![](http://a5.files.readwrite.com/image/upload/c_fit,w_630/MTE5NTU2MzIyNTM0MzI3ODE5.png)
现在我需要通过**cd**（改变路径）命令改变路径进入到`~/experiments`目录中
![](http://a5.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMTMxMTEzOTk5.png)
我的命令提示是系统默认设定，所以它自动显示我当前的工作目录。但是如果你的看起来不一样的话，这样可以让你确定“experiments”是当前工作目录：再一次输入**pwd**。它应该会告诉你当前工作目录是“experiments”。
### 建立存档 ###
在写代码的每一天里我都通过命令行创建和编辑文件。它比使用图形用户界面更快是因为我可以在编辑完后马上就在命令行里测试我的程序。如果我正好同时需要推送到[GitHub][5]的话，好吧，那就更方便了。
现在你有一个新目录（也可以叫做仓库或文件夹）在你电脑上用来折腾。让我们从创建一个包含“你好世界”这句话的文件开始吧。有[很多种方式][6]，在这里我用了**echo**命令。
![](http://a2.files.readwrite.com/image/upload/c_fit,w_630/MTE5NDg0MDYxMjQxMjgwMDE1.png)
哦不！我拼错“newfile”了。这经常会碰到。让我们用两个步骤来改正它。首先，我将创建一个拼写正确的文件...
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MjA5ODAzNzg5.png)
然后，我讲使用**mv**（移动）命令把拼写错误的就文件替换成我的新文件。通常都是这样，“**mv 旧文件 新文件**”。
![](http://a1.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MjA5NzM4MjUz.png)
关于**mv**要注意的：跟大多数命令一样，它是一个容易误导的强大命令。当我们“移动”`newfil.txt`到`newfile.txt`的时候，实际上会把第一个文件完全覆盖到第二个文件上。这样我写到newfile.txt里的内容将彻底消失，替换成我写到newfil.txt里的内容。
为了证明我的目录下只有一个文件，可以使用**ls**，清单命令，来获得目录下的所有文件清单。
![](http://a1.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MTA3NTAyMDkz.png)
看到了没？只有一个。然后如果我在图形界面下看下这个目录的话，也可以看到这个文件。
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDM4OTY0MjM2.png)
但是，它只是个空白文本文件。让我们用文本编辑器来输入点内容进去。在命令行下，我喜欢用`nano`编辑器，因为它很简单而且几乎在所有类型电脑上都可以使用。
这会在你的命令行窗口中马上打开编辑屏幕。一些基本的命令都为你列出来了。
![](http://a3.files.readwrite.com/image/upload/c_fit,w_630/MTIyMzk5Mjg5MDM5NjE5NTk2.png)
写下你想说的话，然后通过CTRL + X退出。在它问你是否保存的时候，当然键入"Y"。
![](http://a4.files.readwrite.com/image/upload/c_fit,w_630/MTIxNDI3Mjk0MTA4MDkxOTE3.png)
你也许已经猜到了，也可以在操作系统中用鼠标找到newfile.txt文件看到这些改动。这里你可以用任意喜欢的文本编辑器打开编辑这个你创建的文件。
如果你想永远删除这个文件，可以用**rm**（移除）命令：
![](http://a2.files.readwrite.com/image/upload/c_fit,w_630/MTE5NTU2MzIyNTQxMzQwMTcx.png)
注意一下，**rm**命令非常强大！在黑客论坛里有个[常用伎俩][7]就是说服一个命令行新手输入**rm -rf /**，然后他就把自己整个电脑上的所有文件都删掉了。命令里的“/”意思是电脑的最高级根目录-所有一切都在它之下。千万不要输入那行命令！
### 延伸阅读 ###
这只是无限可能的命令行的一个开始。你可以使用这个工具控制电脑的每一个方面，这也使得它强大的同时也很危险。保证在使用它们之前先看一下命令行提示，然后永远不要盲目输入任何陌生人推荐给你的语句。
我已经大概介绍了平时敲代码时常用的几个命令，但是有比这更多的理由去掌握命令行。如果你想更彻底地了解，也许可以试试：
[命令行速成教程][8]。一套免费的扩展课程，涵盖了命令行应用的基础。
[命令行初学者启蒙][9]。Lifehacker收藏的一些适合初学者的很有用的命令。
[Mac OS X命令行入门][10]。在线教育网站Treehouse极尽详细地介绍了命令行的基础。
现在文章看完了，你就更容易理解我之前写的那些代码教程了，因为如果不敲几个命令根本没法完成。如果你准备好了，我建议你去看看ReadWrite的[Git教程][11]，它使用命令行来向你介绍协同编程。运算快乐！
*开头图片来自[Jason Scott][12]；其他屏幕截图由Lauren Orsini提供给ReadWrite*
--------------------------------------------------------------------------------
via: http://readwrite.com/2014/07/18/command-line-tutorial-intro
作者：[Lauren Orsini][a]
译者：[zpl1025](https://github.com/zpl1025)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
[a]:http://readwrite.com/author/lauren-orsini
[1]:http://readwrite.com/2014/07/08/what-makes-python-easy-to-learn
[2]:http://readwrite.com/2013/09/30/understanding-github-a-journey-for-beginners-part-1
[3]:http://www.chromium.org/chromium-os/poking-around-your-chrome-os-device
[4]:http://dosprompt.info/
[5]:http://www.github.com/
[6]:http://www.cyberciti.biz/faq/unix-create-file-from-terminal-window-shell-prompt/
[7]:http://www.urbandictionary.com/define.php?term=rm+-rf+%2F
[8]:http://cli.learncodethehardway.org/book/
[9]:http://lifehacker.com/5633909/who-needs-a-mouse-learn-to-use-the-command-line-for-almost-anything
[10]:http://blog.teamtreehouse.com/introduction-to-the-mac-os-x-command-line
[11]:http://readwrite.com/2013/09/30/understanding-github-a-journey-for-beginners-part-1
[12]:http://en.wikipedia.org/wiki/Computer_terminal#mediaviewer/File:DEC_VT100_terminal.jpg