command line - adding a timeout to batch/powershell

Question

$fullnamexp = ((net user $winxp /domain | Select-String "Full Name") -replace "Full Name","").Trim();

If $winxp cannot be found, the command will hang, is there a timeout I can use with this to make it move on after 5-10 seconds? Not sure where I would put it.

Edit- I use this to pull the username:

$reg  = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey('LocalMachine', $tag1)
$key  = $reg.OpenSubKey('SOFTWAREMicrosoftWindows NTCurrentVersionWinLogon')
$winxp = $key.GetValue('DefaultUserName') -replace '^.*?\'

$winxp is then a login name such as ajstepanik then I put it into: $fullnamexp = ((net user $winxp /domain | Select-String "Full Name") -replace "Full Name","").Trim();

1.21.2014 Update

 $timeoutSeconds = 5
$code = {
    ((net user $winxp /domain | Select-String "Full Name") -replace "Full Name","").Trim(); # your commands here, e.g.
}
$j = Start-Job -ScriptBlock $code
if (Wait-Job $j -Timeout $timeoutSeconds) { $fullnamexp = Receive-Job $j }
Remove-Job -force $j

Answer 1

While @mjolinor may have indeed provided you an alternative approach, here is a direct answer to your general question: how do you force a timeout in PowerShell?

Wrap whatever you wish to time-limit in a script block, run that as a job, then use the Wait-Job cmdlet to time-limit the operation. Wait-Job will return either at the end of the timeout period or when the script block completes, whichever occurs first. After Wait-Job returns, you can examine the job state ($j.state) to determine whether it was interrupted or not, if it matters to you.

$timeoutSeconds = 5 # set your timeout value here
$j = Start-Job -ScriptBlock {
    # your commands here, e.g.
    Get-Process
    }
"job id = " + $j.id # report the job id as a diagnostic only
Wait-Job $j -Timeout $timeoutSeconds | out-null
if ($j.State -eq "Completed") { "done!" }
elseif ($j.State -eq "Running") { "interrupted" }
else { "???" }
Remove-Job -force $j #cleanup

2014.01.18 Update

Here is a bit more streamlining approach that also includes the practical step of getting information out of the script block with Receive-Job, assuming what you want is generated on stdout:

$timeoutSeconds = 3
$code = {
    # your commands here, e.g.
    Get-ChildItem *.cs | select name
}
$j = Start-Job -ScriptBlock $code
if (Wait-Job $j -Timeout $timeoutSeconds) { Receive-Job $j }
Remove-Job -force $j