Replace method is not working on my string variables - powershell

Question

I wrote a script to extract the URL and Revision Number from svn info command of a svn repository and save the result in a .txt file.
The $revision and $url are both strings, so the replace method should work on them but it doesn't. Is there possibly something wrong in my code causing this?
$TheFilePath = "C:\Users\MyPC\REPOSITORY\NewProject\OUTPUT.txt"
echo "#- Automatic Package Update `n----------"| Out-File -FilePath $TheFilePath
$url = svn info C:\Users\MyPC\REPOSITORY\NewProject\trunk | Select-String -Pattern 'URL' -CaseSensitive -SimpleMatch | select-object -First 1
$url | Add-Content -path $TheFilePath
$revision = svn info C:\Users\MyPC\REPOSITORY\NewProject\trunk | Select-String -Pattern 'Revision' -CaseSensitive -SimpleMatch | $revision.Replace('Revision','srcrev')
$revision | Add-Content -path $TheFilePath
here is the output of svn info (Irrelevant outputs have been omitted) :
Path: .
Working Copy Root Path: C:\Users\MyPC\REPOSITORY\NewProject\trunk
URL: https://svn.mycompany.de/svn/NewProject/trunk
Relative URL: ^/trunk
Repository Root: https://svn.mycompany.de/svn/NewProject
Revision: 5884
And here is what I get inside the .txt file , running the code :
#- Automatic Package Update
----------
URL: https://svn.mycompany.de/svn/NewProject/trunk
Revision: 5884
----------

Answer 1

Looking at the example output of svn info here and the example you just provided, you should be able to get the info you need easier with ConvertFrom-StringData then with Select-String.
In PowerShell < 7.x you can use ConvertFrom-StringData on the output of svn info after changing the colon (:) delimiter into an equal sign (=) to get a Hashtable with all properties and values.
Then, using calculated properties you can extract the items you're interested in and save as CSV file for instance like this:
$svnInfo = svn info 'C:\Users\MyPC\REPOSITORY\NewProject\trunk'
$result = $svnInfo -replace '(?<!:.*):', '=' | ConvertFrom-StringData |
Select-Object #{Name = 'URL'; Expression = {$_['URL']}},
#{Name = 'srcrev'; Expression = {$_['Revision']}}
# output on screen
$result | Format-Table -AutoSize
# output to CSV file
$result | Export-Csv -Path 'C:\Users\MyPC\REPOSITORIES\NewProject\OUTPUT.csv' -NoTypeInformation
Regex details on the -replace to replace only the first occurrence of the colon:
(?<! Assert that it is impossible to match the regex below with the match ending at this position (negative lookbehind)
: Match the character “:” literally
. Match any single character
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)
: Match the character “:” literally
If you're using PowerShell 7 or higher, tghings get easier because then you have an extra -Delimiter parameter:
$svnInfo = svn info 'C:\Users\MyPC\REPOSITORY\NewProject\trunk'
$result = $svnInfo -replace '(?<!:.*):', '=' | ConvertFrom-StringData -Delimiter ':' |
Select-Object #{Name = 'URL'; Expression = {$_['URL']}},
#{Name = 'srcrev'; Expression = {$_['Revision']}}
# output on screen
$result | Format-Table -AutoSize
# output to CSV file
$result | Export-Csv -Path 'C:\Users\MyPC\REPOSITORIES\NewProject\OUTPUT.csv' -NoTypeInformation

Answer 2

$revision doesn't exist until after the svn command is done.
Use the ForEach-Object cmdlet and refer to the current match as $_ to modify the output object inline - the matched line in the output from Select-String is stored in a property called Line:
$revision = svn info C:\Users\MyPC\REPOSITORY\NewProject\trunk |Select-String -Pattern 'Revision' -CaseSensitive -SimpleMatch |ForEach-Object { $_.Line.Replace('Revision', 'srcrev') }