What is `$?` in Powershell?

Question

What is the meaning of $? in Powershell?

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Edit: TechNet answers in tautology, without explaining what \'succeed\' or \'fail\' mean.

Answer 1

You can also access last commands exit code using $LastExitCode parameter.

# run some command
# ...
if ((! $?) -and $ErrorAction -eq "Stop") { exit $LastExitCode }