July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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340
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附录
C
现在你学会了如何列出不同文件夹下的文件，下面我们来学习如何改变当前所在文件夹。
我们利用
cd
命令来“改变目录”（
change directory
）。试着输入：
cd ~/Downloads
现在用
pwd
查看位于哪个文件夹，用
ls
查看文件夹中的文件，你应该会发现正位于
Downloads
文件夹下。如果你想回到主文件夹的话，应该怎么做？我们知道主文件夹是上
一级文件夹。你可以用
..
跳转到上一级文件夹。试着输入：
cd ..
现在你回到了主文件夹。在
bash
中，
..
的意思是“跳转到上一级目录”。你还可以连用两
次，跳转到上两级目录，像这样：
cd ../..
。
在命令行中跳转目录或选择文件时，你应该可以用
Tab
键自动补全文件名和
文件夹名。对于你想选择的文件或文件夹，先输入名字的第一个字母或前两
个字母，然后只需按下
Tab
键，你应该会看到不同的匹配选择（帮你完成名
字的拼写）。如果没有类似名字的其他文件，命令行会将名字自动补全。这
个方法可以节省很多打字的时间！
现在你应该更习惯于用命令行来跳转目录。下面我们将学习如何用命令行移动文件和修改
文件。
C.1.2
修改文件
利用
bash
移动文件、复制文件和创建文件都很简单。我们先来看创建新文件。首先，跳转
到
home
目录（
cd ~
）。然后输入下列内容：
touch test_file.txt
然后再继续输入
ls
。你应该会看到有一个叫作
test_file.txt
的新文件。
touch
可以用来创建
新文件。这个命令会寻找叫这个名字的文件。如果有这个文件的话，会改变最后一次修改 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.