调用其他程序时的Powershell变量扩展 [英] Powershell variable expansion when calling other programs

问题描述

我在尝试使用 7zaPowershell 中的命令行实用程序.

I have a small problem trying to unzip a file using the 7za command-line utility in Powershell.

我将 $zip_source 变量设置为 zip 文件的路径和$unzip_destination 到所需的输出文件夹.

I set the $zip_source variable to the zip file's path and the $unzip_destination to the desired output folder.

然而，7za 的命令行使用需要这样指定的参数:

However the command-line usage of 7za needs arguments specified like this:

7za x -y <zip_file> -o<output_directory>

所以我目前的电话是这样的:

So my current call looks like this:

& '7za' x -y "$zip_source" -o$unzip_destination

由于 -o 和目标之间不能有空格似乎 PowerShell 不会扩展 $unzip_destination 变量，而 $zip_source 已扩展.

Due to the fact that there can be no space between -o and the destination it seems that PowerShell will not expand the $unzip_destination variable, whereas $zip_source is expanded.

目前程序只是将所有文件解压到C:\的根目录下一个名为 $unzip_destination 的文件夹.在变量周围设置不同类型的引号也不起作用:

Currently the program simply extracts all the files into the root of C:\ in a folder named $unzip_destination. Setting different types of quotes around the variable won't work neither:

-o"$unzip_destination" : still extracts to C:\$unzip_destination
-o'$unzip_destination' : still extracts to C:\$unzip_destination
-o $unzip_destination  : Error: Incorrect command line

有没有什么办法可以在运行命令之前强制展开?

Is there any way to force an expansion before running the command?

推荐答案

试试这个:

-o $($unzip_destination)

^{编者注:此解决方案仅适用于 -o 后的空格(在这种情况下，只需 -o $unzip_destinationdo) - 如果删除它，该命令将无法按预期工作.
因此，这种方法不适合按照 OP 的要求将变量值直接附加到选项名称.}

^{Editor's note: This solution only works with a space after -o (in which case just -o $unzip_destination would do) - if you remove it, the command doesn't work as intended.
This approach is therefore not suitable for appending a variable value directly to an option name, as required by the OP.}

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