PowerShell function doesn't produce output

Question

Sorry if this is a basic question, I'm a PS beginner... How come the following Powershell function runs fine and writes output to the console when I add it to $Profile, but doesn't produce any output when I run it as a .ps1? (When I run as a script, it seems to run but doesn't return any output or error.

My execution policy = unrestricted and I'm running as administrator. Thoughts?

    function Get-NetStats
    { 
        $properties = 'Protocol','LocalAddress','LocalPort' 
        $properties += 'RemoteAddress','RemotePort','State','ProcessName','PID'

        netstat -ano | Select-String -Pattern '\s+(TCP|UDP)' | ForEach-Object {

            $item = $_.line.split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)

            if($item[1] -notmatch '^\[::') 
            {            
                if (($la = $item[1] -as [ipaddress]).AddressFamily -eq 'InterNetworkV6') 
                { 
                   $localAddress = $la.IPAddressToString 
                   $localPort = $item[1].split('\]:')[-1] 
                } 
                else 
                { 
                    $localAddress = $item[1].split(':')[0] 
                    $localPort = $item[1].split(':')[-1] 
                } 

                if (($ra = $item[2] -as [ipaddress]).AddressFamily -eq 'InterNetworkV6') 
                { 
                   $remoteAddress = $ra.IPAddressToString 
                   $remotePort = $item[2].split('\]:')[-1] 
                } 
                else 
                { 
                   $remoteAddress = $item[2].split(':')[0] 
                   $remotePort = $item[2].split(':')[-1] 
                } 

                New-Object PSObject -Property @{ 
                    PID = $item[-1] 
                    ProcessName = (Get-Process -Id $item[-1] -ErrorAction SilentlyContinue).Name 
                    Protocol = $item[0] 
                    LocalAddress = $localAddress 
                    LocalPort = $localPort 
                    RemoteAddress =$remoteAddress 
                    RemotePort = $remotePort 
                    State = if($item[0] -eq 'tcp') {$item[3]} else {$null} 
                } | Select-Object -Property $properties 
            } 
        } 
    }

"*I never call my function, so it never runs. Why doesn't it output anything?*" — TessellatingHeckler, Dec 05 '16 at 18:20

score 2 · Answer 1 · answered Dec 05 '16 at 19:14

TessellatingHeckler got it right, although perhaps not quite as clearly as, and maybe a little more snarky than, I'd have put it:

Simply stated, your .ps1 defines the function Get-NetStats but it doesn't call the function. Without calling the function, you won't get any output from it.

Once you run the .ps1 - or, if the function definition is in your profile - the function will be defined, and can be called any time you need it within that PowerShell session simply by typing Get-NetStats.

score 1 · Answer 2 · edited May 23 '17 at 11:45

1

I found a procedure that helped me figure this out. It's located here:

In PowerShell, how do I define a function in a file and call it from the PowerShell commandline?

Now, I need to figure out how to deploy my new function to remote hosts, maybe via GPO or another PowerShell script...

Cheers!

edited May 23 '17 at 11:45

Community

1
1

answered Dec 05 '16 at 18:47

Tom Blue

31
1
4

score 1 · Answer 3 · answered Dec 05 '16 at 21:16

In order to see output from a function that lives in a .ps1 file when running the .ps1 file, you need to add the function call inside the script.

For example, say I create the following file: Do-AlmostNothing.ps1

# Do-AlmostNothing.ps1
# define the function doNotSoMuch
function doNotSoMuch {
   Write-Host "Look how little I've accomplished!"
}
# execute the function defined above
doNotSoMuch

Without the call to the function, nothing will happen.

Execute the script:

PS> ./Do-AlmostNothing.ps1
Look how little I've accomplished!
PS>

score 0 · Answer 4 · answered Dec 05 '16 at 18:01

0

Are you sure you just don't need to output the return result in your script? When you run a function from $Profile in a powershell window the result is returned to that window. In a script this is not the case.

In the script try:

$result = Get-NetStats
$result

answered Dec 05 '16 at 18:01

Asnivor

266
1
8

I've have tried to pipe the function to Write-Host to no avail, which I think should produce any output to the console. – Tom Blue Dec 05 '16 at 18:27

score 0 · Answer 5 · answered Dec 05 '16 at 21:29

0

You can try something like this

$myStaff = Get-NetStats
Write-output "$myStaff"

answered Dec 05 '16 at 21:29

vitali haradkou

37
6

PowerShell function doesn't produce output

5 Answers5

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