Powershell : Filter using regex and replace matched substring

Question

This seems like a very basic thing to do, but I am new to PowerShell and can't figure this out or find an example online.

I am reading a json file and checking whether any key, value pair has double underscore(__) substring as value. I need to replace that substring with some actual value.

Suppose below is my json file.

"parameters": {
     "tenantId": {
         "value": "adf/__TENANT_ID_AG08__"
      }

 }

And I am trying with the below code to find any substring which starts and ends with double underscore(__TENANT_ID_AG08__ in above example). It is unable to get any matches:

Get-ChildItem -Path $dirPath -Recurse -Filter *.json | 
Foreach-Object {
    $content = Get-Content $_.FullName 

    #Get all the matches with __*ag*__ in a file and replace it with the actual values.
    # UNABLE to get any match. 
    $placeholders = $content | Where-Object {$_ -match '__*AG*__'} 
    
    
    foreach($placeholer in $placeholers) {
       
       #Logic to replace the substring. 
       #...
       #...
       #..
        
    }
}

Assuming, in the above example I have __TENANT_ID_AG08__ value available which I read from the config file and I need to replace that substring.

How can I fix this?

`*` is a quantifier, `_*` matches zero or more `_` chars. You may use `.*` to match any text. Or `\w*` to match any 0 or more letters, digits or `_` — Wiktor Stribiżew, Jun 23 '20 at 14:03
@WiktorStribiżew the solution provided in the link does not seem to be working. — Vikas Gupta, Jun 23 '20 at 14:26
[It does](https://regex101.com/r/5KoEMm/1). [It does, too](https://regex101.com/r/5KoEMm/2) — Wiktor Stribiżew, Jun 23 '20 at 14:28
@WiktorStribiżew I tried with `$placeholders = $content | Where-Object {$_ -match "__\w*AG\w*__"} ` and getting `"value": "adf/__TENANT_ID_AG08__" ` whereas I need only `__TENANT_ID_AG08__`. — Vikas Gupta, Jun 23 '20 at 14:37
If you want to *replace*, why `-match`? `| % {$_ -replace '__\w*AG\w*__', 'new_value'}` — Wiktor Stribiżew, Jun 23 '20 at 14:43
First I need to read `__TENANT_ID_AG08__ ` value from another config file and then only I can replace it. — Vikas Gupta, Jun 23 '20 at 14:47

Powershell : Filter using regex and replace matched substring

0 Answers0