PowerShell: -replace, regex and ($) dollar sign woes

Question 1

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:


<h1>Question:</h1>




<div class="s-prose js-post-body" itemprop="text"><code>

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
</code></div>

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Question:

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

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 (
<h1>Question:</h1>




<div class="s-prose js-post-body" itemprop="text"><code>

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:

<pre><code>
<h1>Question:</h1>




<div class="s-prose js-post-body" itemprop="text"><code>

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
</code></div>

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$origString = @'

IF /I "%OPERATINGSYSTEM:~0,6%"=="WIN864" SET CACHE_OS=WIN864

...many more lines of batch code

'@

$replacedString = $origString -replace "(IF /I `"%)(.+)(:.+%`"==`")(.+`")(.+)","if (

Question:

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:

`Question:`

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

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.

$2 -match "^$4 ) {`$5 }”

$replacedString

Question 2

You could try something like this:

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

1 2	$origString -replace "(IF /I `"%)(.+)(:.+%`"==`")(.+`")(.+)",'if ($$2 -match "^$4" ) {$5 }'

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

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

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'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