PowerShell:-替换，正则表达式和($)美元符号出现问题 [英] PowerShell: -replace, regex and ($) dollar sign woes

问题描述

我正在将数千行批处理代码转换为PowerShell.我正在使用正则表达式来帮助完成此过程.问题是代码的一部分是:

I am in the process of converting thousands of lines of batch code into PowerShell. I'm using regex to help with this process. The problem is part of the code is:

$`$2

替换后，它仅显示$2，并且不会扩展该变量.我还对替换的第二部分使用了单引号，而不是转义变量，结果相同.

When replaced it just shows $2 and doesn't expand out the variable. I've also used single quotes for the second portion of replace instead of escaping the variables, same result.

$origString = @'
IF /I "%OPERATINGSYSTEM:~0,6%"=="WIN864" SET CACHE_OS=WIN864
...many more lines of batch code
'@

$replacedString = $origString -replace "(IF /I `"%)(.+)(:.+%`"==`")(.+`")(.+)","if ( $`$2 -match `"^`$4 ) {`$5 }"

$replacedString

推荐答案

您可以尝试以下方法:

$origString -replace "(IF /I `"%)(.+)(:.+%`"==`")(.+`")(.+)",'if ($$$2 -match "^$4" ) {$5 }'

请注意$$$2.结果为$，内容为$2.

Note the $$$2. This evaluates to $ and content of $2.

一些代码向您显示差异.自己尝试:

Some code to show you the differences. Try it yourself:

'abc' -replace 'a(\w)', '$1'
'abc' -replace 'a(\w)', "$1"  # "$1" is expanded before replace to ''
'abc' -replace 'a(\w)', '$$$1'
'abc' -replace 'a(\w)', "$$$1" #variable $$ and $1 is expanded before regex replace
                               #$$ and $1 don't exist, so they are expanded to ''

$$ = 'xyz'
$1 = '123'
'abc' -replace 'a(\w)', "$$$1`$1" #"$$$1" is expanded to 'xyz123', but `$1 is used in regex

这篇关于PowerShell:-替换，正则表达式和($)美元符号出现问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！