Coloring array filters in PowerShell

user_2272450 0
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Trying to figure out how to color certain filters within an array for ease of reading on console. In other words, as the console progress forward, if "[Behaviour] OnPlayerJoined" appears, color that text green.

$filters = @(
################## FILTERS ##################
"[Behaviour] OnPlayerJoined",
"[Behaviour] OnPlayerLeft ",
"[API] Received Notification: <Notification"
#############################################
)
mode 300
$host.UI.RawUI.ForegroundColor = "White"
$host.UI.RawUI.BackgroundColor = "Black"
cd C:\Users\$env:UserName\AppData\LocalLow\VRChat\VRChat
$taco = Get-ChildItem -Attributes !Directory . | Sort-Object -Descending -Property LastWriteTime | select -First 1
Get-Content -Path $taco.name -Wait | Select-String -Pattern $filters -SimpleMatch
select-string highlight formatting powershell
1 Answers

  • In PowerShell (Core) 7+, you get the desired behavior automatically: in the for-display output for each matching line, Select-String now highlights the part(s) that matched.

    • However, you don't get to control the color for highlighting, which is based on inverting (swapping) the current background and foreground colors; e.g., executing 'oof', 'barn', 'baz' | Select-String 'oo', 'ar', 'az' prints:
      • screenshot PSv7
    • You can opt-out of highlighting with -NoEmphasis.

  • In Windows PowerShell, you'll have to implement your own solution - see below.

The following is a limited solution that would work in your case:

'oof', 'barn', 'baz' |             # sample input
  Select-String 'oo', 'ar', 'az' | # search for sample patter
  ForEach-Object {                 # print the matching parts in green
    $m = $_.Matches[0]
    if ($m.Index -ge 1) { Write-Host -NoNewLine $_.Line.Substring(0, $m.Index) }
    Write-Host -NoNewline -ForegroundColor Green $_.Line.Substring($m.Index, $m.Length)
    Write-Host $_.Line.Substring($m.Index + $m.Length)
  }

Sample output:

screenshot custom implementation

Note:

  • Highlighting multiple matches per input string, in case the -AllMatches switch was specified, is not supported by the above.

  • The C# source code of PowerShell (Core) 7+'s built-in implementation, which does support -AllMatches is in method EmphasizeLine() in class MatchString.cs; permalink as of this writing is here. Note that coloring is achieved by embedding VT (ANSI) escape sequences in the output strings.

  • For a general-purpose pattern-based output-coloring solution, see this answer, which defines custom function Out-HostColored, also available as a Gist.

user_453750
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