powershell while loop not working as expected

Question

I'm having issue with this while loop. Even when the status is returned as online its still stuck in the while loop... any ideas would be amazing :)

$instance = "(opsworks instance id)"

$status = (Get-OPSInstance -InstanceId $instance  -Region eu-west-1).Status.Trim()
Write-Host "Initial:$status"

while($status -ne 'online' -or $status -ne 'start_failed')
{
  $status = (Get-OPSInstance -InstanceId $instance  -Region eu-west-1).Status.Trim()
  Write-Host "Next:$status!"
}

Change `-or` to `-and`; when it is 'online' it is also 'not start_failed' so the loop still loops. — TessellatingHeckler, Jul 12 '17 at 07:59

score 2 · Accepted Answer · answered Jul 12 '17 at 07:59

2

This is a basic boolean algebra. It happens as online is not equal to start_failed. The -or operator will check both sides of the expression and will return true incase of either matches.

Condition

($status -ne 'online' -and $status -ne 'start_failed')

will be evaluated as false iff $status is neither online nor start_failed.

answered Jul 12 '17 at 07:59

vonPryz

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Thanks! I get what your saying now and totally see where I went wrong! Amazing and thank you :) – Stelly Jul 12 '17 at 08:09

powershell while loop not working as expected

1 Answers1