可以$ {VAR}参数扩展前pressions被嵌套在bash？ [英] Can ${var} parameter expansion expressions be nested in bash?

问题描述

我已经是这样的：

progname=${0%.*}
progname=${progname##*/}

这能嵌套（或没有）成一条线，即单次前pression？

Can this be nested (or not) into one line, i.e. a single expression?

我想，这样只有基本名称是留给剥离路径和扩展了脚本的名字。以上两行正常工作。我的'C'的性质仅仅是让我混淆这些甚至更多。

I'm trying to strip the path and extension off of a script name so that only the base name is left. The above two lines work fine. My 'C' nature is simply driving me to obfuscate these even more.

推荐答案

如果巢，你的意思是这样的：

If by nest, you mean something like this:

#!/bin/bash

export HELLO="HELLO"
export HELLOWORLD="Hello, world!"

echo ${${HELLO}WORLD}

然后不，你不能嵌套 $ {VAR} 前pressions。 bash的语法扩展会不明白。

Then no, you can't nest ${var} expressions. The bash syntax expander won't understand it.

不过，如果我理解你的问题吧，你可能看使用基本名命令 - 这条从给定的文件名的路径，如果有扩展性，条之谓也。例如，运行基本名称/some/path/to/script.sh .SH 将返回剧本。

However, if I understand your problem right, you might look at using the basename command - it strips the path from a given filename, and if given the extension, will strip that also. For example, running basename /some/path/to/script.sh .sh will return script.

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