All we're doing here is taking our string variable and calling the Substring method.

所有我们在这里所做的是取得我们的字符串变量然后调用Substring方法。

youdao

We can use another form of variable expansion to select a specific substring, based on a specific character offset and length. Try typing in the following lines under bash.

可以根据特定字符偏移和长度，使用另一种形式的变量扩展，来选择特定子字符串。

youdao