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powershellnetstatselect-string

Select-String -Quiet not returning True

My script is supposed to get the TCP connection information for VNC and tell me when the connection state is ESTABLISHED. I'm stuck on trying to get a return value of True when using Select-String -Quiet.

PS C:\> $vnc = netstat -ab | select-string "winvnc4.exe" -context 1,0
PS C:\> $vnc

    TCP    0.0.0.0:5800           User:0               LISTENING
>  [winvnc4.exe]
    TCP    0.0.0.0:5900           User:0               LISTENING
>  [winvnc4.exe]
    TCP    [::]:5800              User:0               LISTENING
>  [winvnc4.exe]
    TCP    [::]:5900              User:0               LISTENING
>  [winvnc4.exe]

PS C:\> $vnc | Select-String "LISTENING" -quiet

PS C:\> $vnc | Select-String -Pattern "LISTENING" -quiet

PS C:\> $vnc | Select-String "LISTENING" -simplematch -quiet

As you can see, I tried several different parameters to get a result but nothing is returned.

Solution

  • Your first Select-String produces a list of MatchInfo objects. The information you're after is stored in the Context property of these. You need to expand that before you can run another Select-String on it.

    $vnc | Select-Object -Expand Context |
    Select-Object -Expand PreContext |
    Select-String 'LISTENING' -SimpleMatch -Quiet

    On PowerShell v3 and newer you can use member enumeration to make that a little more compact:

    $vnc | ForEach-Object { $_.Context.PreContext } |
    Select-String 'LISTENING' -SimpleMatch -Quiet