使用命令在bash争论的结果如何呢？ [英] Using the result of a command as an argument in bash?

问题描述

要为所有文件夹中的音乐的播放列表，我在bash使用下面的命令：

To create a playlist for all of the music in a folder, I am using the following command in bash:

ls > list.txt

我想用的结果，在 PWD 作为播放列表的名称（打印工作目录）命令。

I would like to use the result of the pwd (print working directory) command for the name of the playlist.

是这样的：

ls > ${pwd}.txt

这不工作，虽然 - ？谁能告诉我，我需要什么样的语法用来做这样的事情。

That doesn't work though - can anyone tell me what syntax I need to use to do something like this?

编辑：正如评论PWD最终会给出一个绝对路径提到，所以我的播放列表将最终被命名为.TXT在某些目录中 - 德哦！因此，我将不得不削减的路径。感谢察觉了 - ！我可能会花了年龄想知道我的文件了。

As mentioned in the comments pwd will end up giving an absolute path, so my playlist will end up being named .txt in some directory - d'oh! So I'll have to trim the path. Thanks for spotting that - I would probably have spent ages wondering where my files went!

推荐答案

使用反引号替换命令的结果是：

Use backticks to substitute the result of a command:

ls > "`pwd`.txt"

正如指出的兰登， $（CMD）相当于：

ls > "$(pwd).txt"

注意的未处理替换 PWD 是绝对路径，所以上面的命令创建在同一目录作为工作目录中的同名文件，而是用一个 .TXT 扩展。 托马斯Kammeyer 指出，基本名命令条上领先的目录，因此这将创建在当前目录下的文本文件与该目录的名称：

Note that the unprocessed substitution of pwd is an absolute path, so the above command creates a file with the same name in the same directory as the working directory, but with a .txt extension. Thomas Kammeyer pointed out that the basename command strips the leading directory, so this would create a text file in the current directory with the name of that directory:

ls > "`basename "$(pwd)"`.txt"

也感谢 erichui 了解造就了空间问题的路径。

Also thanks to erichui for bringing up the problem of spaces in the path.

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