invoke-command Passing of data/variables in and passing changed and new data/variables out

Question

I'm trying to pass some variables sort-of similar to the below, but it isn't passing back the updated/change data i want. In the small example below can you state the way this should be written to be able to pass the data in and back as shown?

    $myfirstname = Jos
    $sess = new-pssession -computername "superdooperkompooter.domain.local"
    invoke-command -jobname whatsmyname -session $sess -scriptblock {
    #Pass in external parameter
    Param($myfirstname)
#Change #myfirstname ... there's more to it in the real script
$myfirstname = Jon
    $fullname = @()
    $fullname += $myfirstname
    $fullname += "Try"
    $fullname += "Feckta" # So this should be effectively $fullname = @(Jon,Try,Feckta) at this point
    # Now i need to pass back the changed/added variables
    } -Argumentlist ($myfirstname,$fullname)

    # Now when i attempt to show the data it just comes out blank
    write-out $fullname
write-out $myfirstname 

Answer 1

The -ArgumentList is for the variables that goes in. There is no "byRef" here.

What you need to do is to assign your Invoke-Command statement to a variable. From there, when you are ready to return your "multiple variables", you can return them as a hashtable so they are ready to use in your Write-Host statements.

Example

$Output = invoke-command -jobname whatsmyname -session $sess -scriptblock {
  #Pass in external parameter
  Param($myfirstname)
#  ... Your code here
  return @{
    MyFirstName = $myfirstname
    FullName    = $fullname
  }

} -Argumentlist ($myfirstname)

write-out $Output.fullname
write-out $Output.myfirstname 

Additional notes

I am not passing the $fullName to the argument list since you did only define Param($myFirstName) and we established that yhe value would not go out and be assigned to the $fullName variable.