Try method in powershell

Question

So I want to build a try method into my powershell script below. If I am denied access to a server, I want it to skip that server. Please help..

[code]$Computers = "server1", "server2"

Get-WmiObject Win32_LogicalMemoryConfiguration -Computer $Computers | Select-Object `
@{n='Server';e={ $_.__SERVER }}, `
@{n='Physical Memory';e={ "$('{0:N2}' -f ($_.TotalPhysicalMemory / 1024))mb" }}, `
@{n='Virtual Memory';e={ "$('{0:N2}' -f ($_.TotalPageFileSpace / 1024))mb" }} | `
Export-CSV "output.csv"[/code]

Answer 1

You can use trap to replicate Try/Catch, see http://huddledmasses.org/trap-exception-in-powershell/ or http://weblogs.asp.net/adweigert/archive/2007/10/10/powershell-try-catch-finally-comes-to-life.aspx for examples.

Answer 2

Try/catch functionality is built-into PowerShell 2.0 e.g.:

PS> try {$i = 0; 1/$i } catch { Write-Debug $_.Exception.Message }; 'moving on'
Attempted to divide by zero.
moving on

Just wrap you script in a similar try/catch. Note you could totally ignore the error by leaving the catch block empty catch { } but I would recommend at least spitting out the error info if your $DebugPreference is set to 'Continue'.

Answer 3

You can simply suppress errors with the ErrorAction parameter:

Get-WmiObject Win32_LogicalMemoryConfiguration -Computer $Computers -ErrorAction SilentlyContinue | ...

Answer 4

Use a filter function? Like this tutorial explains.

He passes a list of computers to his pipeline - first it tries to ping each one, and then only passes the ones that respond to the next command (reboot). You could customize this for whatever actual functionality you wanted.