在Shell脚本中使用正则表达式 [英] Using regular expressions in shell script

问题描述

在Linux Shell脚本中使用正则表达式解析字符串的正确方法是什么?我编写了以下脚本，以使用curl和sed在控制台上打印我的SO rep(不仅是因为我表示rep -crazy-我试图在切换到linux之前学习一些shell脚本和regex). /p>

What is the correct way to parse a string using regular expressions in a linux shell script? I wrote the following script to print my SO rep on the console using curl and sed (not solely because I'm rep-crazy - I'm trying to learn some shell scripting and regex before switching to linux).

json=$(curl -s http://stackoverflow.com/users/flair/165297.json)
echo $json | sed 's/.*"reputation":"\([0-9,]\{1,\}\)".*/\1/' | sed s/,//

但是以某种方式我觉得sed不是在这里使用的适当工具.我听说grep与正则表达式有关，并对其进行了一些探讨.但是很明显，只要找到匹配项，它就会打印整行-我正试图从一行文本中提取一个数字.这是我正在处理的字符串的缩小版本(由curl返回).

But somehow I feel that sed is not the proper tool to use here. I heard that grep is all about regex and explored it a bit. But apparently it prints the whole line whenever a match is found - I am trying to extract a number from a single line of text. Here is a downsized version of the string that I'm working on (returned by curl).

{"displayName":"Amarghosh"，声誉":"2,737"，"badgeHtml":"\ u003cspan title = \" 1个银色徽章\"\ u003e \ u003cspan class = \" badge2 \"\ u003e& #9679; \ u003c/span \ u003e \ u003cspan class = \"badgecount \" \ u003e1 \ u003c/span \ u003e \ u003c/span \ u003e}

{"displayName":"Amarghosh","reputation":"2,737","badgeHtml":"\u003cspan title=\"1 silver badge\"\u003e\u003cspan class=\"badge2\"\u003e●\u003c/span\u003e\u003cspan class=\"badgecount\"\u003e1\u003c/span\u003e\u003c/span\u003e"}

我想我的问题是:

• 在Linux Shell脚本中使用正则表达式解析字符串的正确方法是什么?
• sed在这里使用正确吗?
• 可以使用grep完成吗?
• 还有其他更简单/更合适的命令吗?

• What is the correct way to parse a string using regular expressions in a linux shell script?
• Is sed the right thing to use here?
• Could this be done using grep?
• Is there any other command that's more easier/appropriate?

推荐答案

grep命令将从许多行中选择所需的行，但不会直接操纵该行.为此，您在管道中使用sed:

The grep command will select the desired line(s) from many but it will not directly manipulate the line. For that, you use sed in a pipeline:

someCommand | grep 'Amarghosh' | sed -e 's/foo/bar/g'

或者，可以使用awk(或perl(如果可用)).在我看来，它是一个比sed更强大的文本处理工具.

Alternatively, awk (or perl if available) can be used. It's a far more powerful text processing tool than sed in my opinion.

someCommand | awk '/Amarghosh/ { do something }'

对于简单的文本操作，只需坚持使用grep/sed组合键即可.当您需要更复杂的处理时，请移至awk或perl.

For simple text manipulations, just stick with the grep/sed combo. When you need more complicated processing, move on up to awk or perl.

我的第一个想法是只使用:

My first thought is to just use:

echo '{"displayName":"Amarghosh","reputation":"2,737","badgeHtml"'
    | sed -e 's/.*tion":"//' -e 's/".*//' -e 's/,//g'

使sed进程数保持为1(您可以使用-e给出多个命令).

which keeps the number of sed processes to one (you can give multiple commands with -e).

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