问题:

I tried some random parameters after the shutdown command in PowerShell 2.0 when I stumbled upon shutdown -y. All it seems to do is log out the user.
if any other random letter is used (that isn't a valid parameter) nothing happens. For example: shutdown -b

My question is: Does shutdown -y do anything special?

I could not find any documentation about this.

回答1:

The Windows 2000 documentation states the following:

/y: Use this switch to force a "yes" answer to all queries from the computer.

So it looks like by using -y or /y with no other switches you are doing the default behaviour of shutdown.exe, which is to logoff the user while also forcing any confirm prompts to be acknowledged with yes.

回答2:

Shutdown is not exactly a PowerShell command. It's the same shutdown.exe that also works in CMD.

Interestingly, the -y command is not mentioned in the documentation. As Mark Wragg found out, it's used to force a "yes" answer for remote shutdown. So, if no other parameters are specified, the default action (logoff user) is executed.

Another question: Why were you trying random parameters? Follow the docu and you're less likely to encounter any unexpected behavior.