string 更改索引 X 处的字符串字符

Question

提问by gdoron is supporting Monica

I'm searched for a long time how to do a simple string manipulation in UNIX

我搜索了很长时间如何在中进行简单的字符串操作 UNIX

I have this string:

我有这个字符串：

theStr='...............'

And I need to change the 5th char to A, How can it be done?

我需要将第 5 个字符更改为 A，怎么办？

In C#it's done like this theStr[4] = 'A'; // Zero based index.

在C#它是这样做的theStr[4] = 'A'; // Zero based index.

Answer 1

You can achieve this with sed, the stream line editor:

您可以使用sed流线编辑器实现此目的：

echo $theStr | sed s/./A/5

First you pipe the output of $theStr to sed, which replaces the fifth character with A.

首先，您将 $theStr 的输出通过管道传送到 sed，后者将第五个字符替换为 A。

Answer 2

a="............"
b="${a:0:4}A${a:5}"
echo ${b}

Here is one really good tutorialon string manipulation.

这是一个关于字符串操作的非常好的教程。

Answer 3

I don't know if it's elegant, or which version of bash you need, but

我不知道它是否优雅，或者你需要哪个版本的 bash，但是

theStr="${theStr:0:4}A${theStr:5}"

The first part returns first four characters, then the character 'A', and then all the characters starting with the 6th one

第一部分返回前四个字符，然后是字符“A”，然后是从第 6 个字符开始的所有字符