Error Handling Issue with Try/Catch in Powershell - powershell

Question

I have been working on the following example from one of Don Jones' powershell books as part of my personal development and am having some serious trouble getting the try/catch construct to work as it should. As you can see, when the catch block executes, it sets a variable called $everything_ok to $false - which should trigger the else block in the following code. Which it does - the logfile is appended as per my expectations.
However it does not stop the script from ALSO executing the code in the if block and spewing out 'The RPC Server is unavailable' errors when it tries to query the made-up machine 'NOTONLINE' (Exception type is System.Runtime.InteropServices.COMException).
What makes this even stranger is that I went through the script with breakpoints, checking the contents of the $everything_ok variable along the way, and it never contained the wrong value at any point. So why on earth is the if block still executing for 'NOTONLINE' when the condition I have specified ( if ($everything_ok = $true) ) has not been met?
Am I doing something wrong here?
function get-systeminfo {
<#
.SYNOPSIS
Retrieves Key Information on 1-10 Computers
#>
[cmdletbinding()]
param (
[parameter(mandatory=$true,valuefrompipeline=$true,valuefrompipelinebypropertyname=$true,helpmessage="computer name or ip address")]
[validatecount(1,10)]
[validatenotnullorempty()]
[alias('hostname')]
[string[]]$computername,
[string]$errorlog = "C:\retry.txt",
[switch]$logerrors
)
BEGIN {
write-verbose "Error log will be $errorlog"
}
PROCESS {
foreach ($computer in $computername) {
try {$everything_ok = $true
gwmi win32_operatingsystem -computername $computer -ea stop
} catch {
$everything_ok = $false
write-verbose "$computer not Contactable"
}
if ($everything_ok = $true) {
write-verbose "Querying $computer"
$os = gwmi win32_operatingsystem -computername $computer
$cs = gwmi win32_computersystem -computername $computer
$bios = gwmi win32_bios -computername $computer
$props = #{'ComputerName' = $cs.__SERVER;
'OSVersion' = $os.version;
'SPVersion' = $os.servicepackmajorversion;
'BiosSerial' = $bios.serialnumber;
'Manufacturer' = $cs.manufacturer;
'Model' = $cs.model}
write-verbose "WMI Queries Complete"
$obj = new-object -type psobject -property $props
write-output $obj
}
elseif ($everything_ok = $false) {
if ($logerrors) {
"$computer $_" | out-file $errorlog -append
}
}
}
}
END {}
}
get-systeminfo -host localhost, NOTONLINE -verbose -logerrors

Answer 1

The equals sign in Powershell is used as the assignment operation. -eq is used to test for equality. So your if statement is assigning $true to $everything_ok, which then tests true.