mirror of
https://github.com/LCTT/TranslateProject.git
synced 2025-01-25 23:11:02 +08:00
完成翻译 (#5697)
* translated by xllc * Delete 20170515 How I got started with bash scripting.md
This commit is contained in:
xllc
Ezio
parent
e5043770bd
commit
e0a2f67385
@ -1,138 +0,0 @@
|
||||
【xllc翻译中】
|
||||
|
||||
How I got started with bash scripting
|
||||
============================================================
|
||||
|
||||
### With a few simple Google searches, a programming novice learned to write code that automates a previously tedious and time-consuming task.
|
||||
|
||||
|
||||
|
||||
|
||||
>Image by : opensource.com
|
||||
|
||||
I wrote a script the other day. For some of you, that sentence sounds like no big deal. For others, and I know you're out there, that sentence is significant. You see, I'm not a programmer. I'm a writer.
|
||||
|
||||
### What I needed to solve
|
||||
|
||||
My problem was fairly simple: I had to juggle files from engineering into our documentation. The files were available in a .zip format from a web URL. I was copying them to my desktop manually, then moving them into a different directory structure to match my documentation needs. A fellow writer gave me this advice: _"Why don't you just write a script to do this for you?"_
|
||||
|
||||
Programming and development
|
||||
|
||||
* [New Python content][1]
|
||||
|
||||
* [Our latest JavaScript articles][2]
|
||||
|
||||
* [Recent Perl posts][3]
|
||||
|
||||
* [Red Hat Developers Blog][4]
|
||||
|
||||
|
||||
|
||||
I thought _"just write a script?!?"_ —as if it was the easiest thing in the world to do.
|
||||
|
||||
### How Google came to the rescue
|
||||
|
||||
My colleague's question got me thinking, and as I thought, I googled.
|
||||
|
||||
**What scripting languages are on Linux?**
|
||||
|
||||
This was my first Google search criteria, and many of you are probably thinking, "She's pretty clueless." Well, I was, but it did set me on a path to solving my problem. The most common result was Bash. Hmm, I've seen Bash. Heck, one of the files I had to document had Bash in it, that ubiquitous line **#!/bin/bash**. I took another look at that file, and I knew what it was doing because I had to document it.
|
||||
|
||||
So that led me to my next Google search request.
|
||||
|
||||
**How to download a zip file from a URL?**
|
||||
|
||||
That was my basic task really. I had a URL with a .zip file containing all the files I needed to include in my documentation, so I asked the All Powerful Google to help me out. That search gem, and a few more, led me to Curl. But here's the best part: Not only did I find Curl, one of the top search hits showed me a Bash script that used Curl to download a .zip file and extract it. That was more than I asked for, but that's when I realized being specific in my Google search requests could give me the information I needed to write this script. So, momentum in my favor, I wrote the simplest of scripts:
|
||||
|
||||
```
|
||||
#!/bin/sh
|
||||
|
||||
curl http://rather.long.url | tar -xz -C my_directory --strip-components=1
|
||||
```
|
||||
|
||||
What a moment to see that thing run! But then I realized one gotcha: The URL can change, depending on which set of files I'm trying to access. I had another problem to solve, which led me to my next search.
|
||||
|
||||
**How to pass parameters into a Bash script?**
|
||||
|
||||
I needed to be able to run this script with different URLs and different end directories. Google showed me how to put in **$1**, **$2**, etc., to replace what I typed on the command line with my script. For example:
|
||||
|
||||
```
|
||||
bash myscript.sh http://rather.long.url my_directory
|
||||
```
|
||||
|
||||
That was much better. Everything was working as I needed it to, I had flexibility, I had a working script, and most of all, I had a short command to type and save myself 30 minutes of copy-paste grunt work. That was a morning well spent.
|
||||
|
||||
Then I realized I had one more problem. You see, my memory is short, and I knew I'd run this script only every couple of months. That left me with two issues:
|
||||
|
||||
* How would I remember what to type for my script (URL first? directory first?)?
|
||||
|
||||
* How would another writer know how to run my script if I got hit by a truck?
|
||||
|
||||
I needed a usage message—something the script would display if I didn't use it correctly. For example:
|
||||
|
||||
```
|
||||
usage: bash yaml-fetch.sh <'snapshot_url'> <directory>
|
||||
```
|
||||
|
||||
Otherwise, run the script. My next search was:
|
||||
|
||||
**How to write "if/then/else" in a Bash script?**
|
||||
|
||||
Fortunately I already knew **if/then/else** existed in programming. I just had to find out how to do that. Along the way, I also learned to print from a Bash script using **echo**. What I ended up with was something like this:
|
||||
|
||||
```
|
||||
#!/bin/sh
|
||||
|
||||
URL=$1
|
||||
DIRECTORY=$2
|
||||
|
||||
if [ $# -eq 0 ];
|
||||
then
|
||||
echo "usage: bash yaml-fetch.sh <'snapshot_url'> <directory>".
|
||||
else
|
||||
|
||||
# make the directory if it doesn't already exist
|
||||
echo 'create directory'
|
||||
|
||||
mkdir $DIRECTORY
|
||||
|
||||
# fetch and untar the yaml files
|
||||
echo 'fetch and untar the yaml files'
|
||||
|
||||
curl $URL | tar -xz -C $DIRECTORY --strip-components=1
|
||||
fi
|
||||
```
|
||||
|
||||
### How Google and scripting rocked my world
|
||||
|
||||
Okay, slight exaggeration there, but this being the 21st century, learning new things (especially somewhat simple things) is a whole lot easier than it used to be. What I learned (besides how to write a short, self-documented Bash script) is that if I have a question, there's a good chance someone else had the same or a similar question before. When I get stumped, I can ask the next question, and the next question. And in the end, not only do I have a script, I have the start of a new skill that I can hold onto and use to simplify other tasks I've been avoiding.
|
||||
|
||||
Don't let that first script (or programming step) get the best of you. It's a skill, like any other, and there's a wealth of information out there to help you along the way. You don't need to read a massive book or take a month-long course. You can do it a simpler way with baby steps and baby scripts that get you started, then build on that skill and your confidence. There will always be a need for folks to write those thousands-of-lines-of-code programs with all the branching and merging and bug-fixing.
|
||||
|
||||
But there is also a strong need for simple scripts and other ways to automate/simplify tasks. And that's where a little script and a little confidence can give you a kickstart.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
作者简介：
|
||||
|
||||
Sandra McCann - Sandra McCann is a Linux and open source advocate. She's worked as a software developer, content architect for learning resources, and content creator. Sandra is currently a content creator for Red Hat in Westford, MA focusing on OpenStack and NFV techology.
|
||||
|
||||
----
|
||||
|
||||
via: https://opensource.com/article/17/5/how-i-learned-bash-scripting
|
||||
|
||||
作者：[ Sandra McCann ][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://opensource.com/users/sandra-mccann
|
||||
[1]:https://opensource.com/tags/python?src=programming_resource_menu
|
||||
[2]:https://opensource.com/tags/javascript?src=programming_resource_menu
|
||||
[3]:https://opensource.com/tags/perl?src=programming_resource_menu
|
||||
[4]:https://developers.redhat.com/?intcmp=7016000000127cYAAQ&src=programming_resource_menu
|
||||
[5]:https://opensource.com/article/17/5/how-i-learned-bash-scripting?rate=s_R-jmOxcMvs9bi41yRwenl7GINDvbIFYrUMIJ8OBYk
|
||||
[6]:https://opensource.com/user/39771/feed
|
||||
[7]:https://opensource.com/article/17/5/how-i-learned-bash-scripting#comments
|
||||
[8]:https://opensource.com/users/sandra-mccann
|
||||
@ -0,0 +1,123 @@
|
||||
我是如何开始编写 bash 脚本的？
|
||||
============================================================
|
||||
|
||||
### 通过一些简单的 Google 搜索，即使编程入门者也可以尝试编写代码实现将以往枯燥和冗长的任务自动化。
|
||||
|
||||
|
||||
|
||||
|
||||
>图片来自 : opensource.com
|
||||
|
||||
我前几天写了一个脚本。对于一些人来说，这句话听起来没什么了不起的。而对于另一些人来说，这句话意义重大。要知道，我不是一个程序员，而是一个作家。
|
||||
|
||||
### 我需要解决什么？
|
||||
|
||||
我的问题相当简单：我需要将工程文件进行分类。这些文件可以从一个网站 URL 以 .zip 的格式下载。当我正手工将它们拷贝到我的电脑桌面，并移动到一个已按照我文件分类的需要进行了结构化的目录时，一位作家同事给我提了建议：_“你为什么不就写个脚本来完成这件事呢？”_
|
||||
|
||||
我心想：_“就写个脚本？”_——说得好像这是世界上最容易做的事情一样。
|
||||
|
||||
### Google 是如何解救我的？
|
||||
|
||||
同事的问题促使我思考，并且经过思考后，我进行了 Google 搜索。
|
||||
|
||||
**Linux 上使用的是什么脚本编程语言？**
|
||||
|
||||
这是我第一个 Google 搜索的准则。也许很多人心里会想：“她太笨了！”是的，我很笨。不过，这的确使我走上了一条解决问题的道路。最常见的搜索结果是 Bash 。嗯，我见过 Bash 。呃，我要分类的文件中有一个就有 Bash 在里面，那无处不在的 **#!/bin/bash** 。我重新看了下那个文件，我知道它的用途，因为我需要将它分类。
|
||||
|
||||
这引导我进行了下一个 Google 搜索
|
||||
|
||||
**如何从一个 URL 下载 zip 文件？**
|
||||
|
||||
那确实是我的基本任务。我有一个附带着 .zip 文件的 URL ，它包含有所有我需要分类的文件，所以我寻求万能的 Google 的帮助。搜索到的精华内容和其它一些结果引导我使用 Curl 。但最重要的是：我不仅找到了 Curl ，其中一条置顶的搜索结果还展示了一个使用 Curl 去下载并解压 .zip 文件的 Bash 脚本。这超出了我本来想寻求的答案，但那也使我意识到在 Google 搜索具体的请求可以得到我写这个脚本需要的信息。所以，在收获的推动下，我写了最简单的脚本：
|
||||
|
||||
```
|
||||
#!/bin/sh
|
||||
|
||||
curl http://rather.long.url | tar -xz -C my_directory --strip-components=1
|
||||
```
|
||||
|
||||
我迫不及待地运行看看。但我发现一个问题： URL 是会变的，根据我要访问的文件的分组不同而不同。我有新的问题需要解决，这使我进行了下一轮搜索。
|
||||
|
||||
**参数如何传递给 Bash 脚本？**
|
||||
|
||||
我需要以不同的 URL 和不同的最终目录来运行此脚本。 Google 向我展示了如何使用 **$1**、**$2** 等等来替换我在命令行中运行脚本时输入的内容。比如：
|
||||
```
|
||||
bash myscript.sh http://rather.long.url my_directory
|
||||
```
|
||||
|
||||
这就好多了。一切如我所愿，灵活，实用。最重要的是我只要输入一条简短的命令就可以节省 30 分钟无聊的复制、粘贴工作。这个早上的时间花得值得。
|
||||
|
||||
然后我发现还有一个问题：我很健忘，并且我知道我几个月才运行一次这个脚本。这留给我两个疑问：
|
||||
|
||||
* 我要如何记得运行脚本时输入什么 ( URL 先？还是目录先？)？
|
||||
|
||||
* 如果我被货车撞了，其它作家如何知道该怎样运行我的脚本？
|
||||
|
||||
我需要一个使用说明 —— 如果我使用不正确，则脚本会提示。比如：
|
||||
|
||||
```
|
||||
usage: bash yaml-fetch.sh <'snapshot_url'> <directory>
|
||||
```
|
||||
|
||||
否则，则直接运行脚本。我的下一个搜索是：
|
||||
|
||||
**如何在 Bash 脚本里使用“if/then/else”?**
|
||||
|
||||
幸运的是，我已经知道编程中 **if/then/else** 的存在。我只要找出如何使用它的方法。在这个过程中，我也学到了如何在 Bash 脚本里使用 **echo** 打印。我的最终成果如下：
|
||||
|
||||
```
|
||||
#!/bin/sh
|
||||
|
||||
URL=$1
|
||||
DIRECTORY=$2
|
||||
|
||||
if [ $# -eq 0 ];
|
||||
then
|
||||
echo "usage: bash yaml-fetch.sh <'snapshot_url'> <directory>".
|
||||
else
|
||||
|
||||
# 如果目录不存在则创建它
|
||||
echo 'create directory'
|
||||
|
||||
mkdir $DIRECTORY
|
||||
|
||||
# 下载并解压 yaml 文件
|
||||
echo 'fetch and untar the yaml files'
|
||||
|
||||
curl $URL | tar -xz -C $DIRECTORY --strip-components=1
|
||||
fi
|
||||
```
|
||||
|
||||
### Google 和脚本编程如何震撼我的世界？
|
||||
|
||||
好吧，这稍微有点夸大，不过现在是 21 世纪，学习新东西（特别是稍微简单的东西）比以前简单多了。我所学到的（除了如何写一个简短的、自动分类的 Bash 脚本）是如果我有疑问，那么有很大可能性是其它人在之前也有过相同的疑问。当我困惑的时候，我可以问下一个问题，再下一个问题。最后，我不仅拥有了脚本，还拥有了坚持和习惯于简化其它任务的新技能，这是我之前所没有的。
|
||||
|
||||
别止步于第一个脚本（或者编程的第一步）。这是一个无异于其它的技能，丰富的信息可以在这一路上帮助你。你无需阅读大量的书或参加一个月的课程。你可以像婴儿学步那样简单地开始写脚本，然后掌握技能并建立自信。人们总有写成千上万行代码，包含分支、合并、修复错误的程序的需要。
|
||||
|
||||
但是，通过简单的脚本或其它方式来自动化、简单化任务的需求也一样强烈。这就是一个小脚本和小自信能够让你启程。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
作者简介：
|
||||
|
||||
桑德拉麦肯：桑德拉麦肯是一位 Linux 和开源技术的倡导者。她是一位软件开发者、学习资源内容架构师、内容创作者。桑德拉目前是位于韦斯特福德马萨诸塞州的红帽公司的内容创作者，专注于 OpenStack 和 NFV 技术。
|
||||
|
||||
----
|
||||
|
||||
via: https://opensource.com/article/17/5/how-i-learned-bash-scripting
|
||||
|
||||
作者：[ Sandra McCann ][a]
|
||||
译者：[xllc](https://github.com/xllc)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://opensource.com/users/sandra-mccann
|
||||
[1]:https://opensource.com/tags/python?src=programming_resource_menu
|
||||
[2]:https://opensource.com/tags/javascript?src=programming_resource_menu
|
||||
[3]:https://opensource.com/tags/perl?src=programming_resource_menu
|
||||
[4]:https://developers.redhat.com/?intcmp=7016000000127cYAAQ&src=programming_resource_menu
|
||||
[5]:https://opensource.com/article/17/5/how-i-learned-bash-scripting?rate=s_R-jmOxcMvs9bi41yRwenl7GINDvbIFYrUMIJ8OBYk
|
||||
[6]:https://opensource.com/user/39771/feed
|
||||
[7]:https://opensource.com/article/17/5/how-i-learned-bash-scripting#comments
|
||||
[8]:https://opensource.com/users/sandra-mccann
|
||||
Loading…
Reference in New Issue
Block a user