2

I'm new to PowerShell and am trying to write a script that's dependant on a Hyper-V VM's status. Here's my (basic) if statement:

if((get-vm WMDC2 | out-string) -like '*Running*') { echo "running"}

I feel like there has to be a better way of doing this, but I don't know what it is. I don't think this is a bad way of doing it, but as I'm trying to learn, I'd like to know if there is a better way and if this is a bad way of doing this, why.

EDIT:

As mentioned in the first answer, my only idea was to convert to a string to check the object's properties against something I'm looking for. I'd like if there were a way to do this without converting my output to a string, and that is essentially what I'm looking for.

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4

The Format-* cmdlets (your fl is Format-List) are to format output for view in the console. Do not re-parse them for values. Collect the object(s) returned by the Get-VM and access the properties directly.

# Get the VM object
$vm = Get-VM WMDC2
# check if the 'state' property equals 'Running'
if ($vm.state -eq 'Running') {
   Write-Host 'Running'
}

And if you absolutely do not want to store the VM object for some reason you can also shorthand it like this.

if ((Get-VM WMDC2).state -eq 'Running'){
  Write-Host 'Running'
}

I don't think this is a bad way of doing it

It is a bad way of doing it, but it's not your fault. It's common that beginning Powershellers jump in and start trying to string-ify all the things. Without delving too far into Powershell objects, the worst part of this approach is that you lose the usefulness built-in (properties, methods, pipeline-ability) to the object returned by Get-VM.

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  • I tagged the question as Hyper-V, but I'll add it to the question for clarity. I was unaware that PowerCLI was PowerShell compatible so I didn't think to specify. Also, I thought converting the one line I needed to a string would be better than converting the whole output to a string. Is there a way to optimize in that way? I realize that in this situation, the full list of properties is really short, but I'll eventually be working with things that have a great many more properties. On top of that, I'd like to be able to target specific properties rather than the whole output. – MagnaVis Aug 24 '17 at 15:23
  • @MagnaVis PowerCLI is VMware's Powershell modules/console for working with vSphere and more. – jscott Aug 24 '17 at 15:25
  • Cool, I don't use VMware's offerings, so I had no idea. Thanks! – MagnaVis Aug 24 '17 at 15:27
  • @MagnaVis Both my examples show how to only target the state property. I've change the -like to -eq to remove any ambiguity. – jscott Aug 24 '17 at 15:43
  • This is exactly what I was looking for, thank you! – MagnaVis Aug 24 '17 at 15:46

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