Using Powershell's bitwise operators

问题

I'm looking for example of how I would solve the scenario below:

Imagine my printer has the following property for "Status"
0 -Offline
2 -Paper Tray Empty
4 -Toner Exhausted
8 -Paper Jam

When I query status it returns a value of 12. I can obviously see that this means the printer has the Toner Exhausted and a Paper Jam, but how would I work this out with Powershell?

Thanks

回答1:

The boolean bitwise and operator in Powershell is -band.

Assume you define your values and descriptions in a hashtable, and have the value of 12 from the printer:

 $status = @{1 = "Offline" ; 2 = "Paper Tray Empty" ; 4 = "Toner Exhausted" ; 8 = "Paper Jam" }
 $value = 12

Then, this statement will give you the textual descriptions:

$status.Keys | where { $_ -band $value } | foreach { $status.Get_Item($_) }

You could define the enum in Powershell, but the above works just as well, and defining enums in Powershell seems like a lot of work.

Here is an article, that talks about how to use the bitwise operators in Powershell.

回答2:

You can let PowerShell do more of the work for you. Here's an example using System.IO.FileOptions:

PS> [enum]::GetValues([io.fileoptions]) | ?{$_.value__ -band 0x90000000}
RandomAccess
WriteThrough

来源：https://stackoverflow.com/questions/2648052/using-powershells-bitwise-operators