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Conditions, Loops and Using the Pipeline in Scripts: switch, foreach, Where-Object, ForEach-Object and -Parallel

In PowerShell the foreach statement is the fastest on a collection in memory, while for data streaming from a file the pipeline does far less work because it can stop early; a break inside ForEach-Object skips the rest of the script. We show comparison operators, reading logs with switch -Regex, begin/process/end blocks and ForEach-Object -Parallel with a script that checks Bookstore's 200 book covers, along with the $using:, race condition and Format-Table traps.