在Bash变量分配的右侧引用时，波浪号没有扩展 [英] Tilde not expanded when quoting on the right hand side of a Bash variable assignment

问题描述

我已经创建了一个目录〜/ test_myDir

I have made a directory ~/test_myDir

然后运行以下bash脚本：

I then run the following bash script:

x="myDir"

dirName="~/test_$x"

cd $dirName
echo "hey" > test.txt

我收到以下错误：

test.sh: line 5: cd: ~/test_myDir: No such file or directory

然后从第二个作业中删除引号：

I then remove the quotes from the second assignment:

x="myDir"

dirName=~/test_$x

cd $dirName
echo "hey" > test.txt

脚本运行无错误。

这是怎么回事？我在一个更大，更复杂的脚本中遇到了这个问题，然后将其范围缩小到我在包含另一个变量的变量赋值中使用引号。

What is going on here? I ran into this issue in a larger, more complicated script, and I narrowed it down to my use of quotes in a variable assignment that contained another variable.

错误消息，似乎完整路径已在 cd调用中正确扩展。

Still, from the error message, it looks like the full path is being expanded correctly in the "cd" call.

推荐答案

引号阻止扩展〜。将〜替换为 $ HOME 或使用 dirName =〜/ test_ $ x 。

Quotation marks prevent expansion of ~. Replace ~ with $HOME or use dirName=~/"test_$x".

根据手册中对代字扩展的解释：

From the manual's explanation of tilde expansion:

检查每个变量赋值是否紧跟在：或第一个=之后的不带引号的前缀。在这些情况下，也会执行波浪线扩展
。

Each variable assignment is checked for unquoted tilde-prefixes immediately following a : or the first =. In these cases, tilde expansion is also performed.

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