Running PowerShell command from CMD gives positional parameter error

Question

I have this PowerShell command:

Get-WmiObject -Query "Select * from CIM_DataFile Where Extension = 'ost'" |
    Select-Object 'Name' |
    Out-File C:\temp\ost.txt -Append

But I need to run it form a command prompt. I'm running it like this:

powershell.exe -ExecutionPolicy ByPass -Command "Get-WmiObject -Query "Select * from CIM_DataFile Where Extension = 'ost'" | Select-Object 'Name' | Out-File C:\temp\ost.txt -Append"

I'm getting this error:

Get-WmiObject : A positional parameter cannot be found that accepts argument '*'.
At line:1 char:1
+ Get-WmiObject -Query Select * from CIM_DataFile Where Extension = 'os ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Get-WmiObject], ParameterBindingException
    + FullyQualifiedErrorId : PositionalParameterNotFound,Microsoft.PowerShell.Commands.GetWmiObjectCommand

How do I run this correctly?

Use single-quotes for the `-Query` parameter and escape your double-quotes with `^`. — Maximilian Burszley, Nov 14 '18 at 17:45
Escape the nested double quotes with backslashes: `"Get-WmiObject -Query \"Select * from ...\" | ..."` — Ansgar Wiechers, Nov 14 '18 at 17:50
@AnsgarWiechers Why ``\``? I thought the `cmd` escape was `^` — Maximilian Burszley, Nov 14 '18 at 17:56
Don't ask me why. All I can tell you is that `^` is the escape character in CMD *most* of the time. ;) — Ansgar Wiechers, Nov 14 '18 at 17:57
@TheIncorrigible1: It is _PowerShell_ that requires `\ `-escaping of `"` chars. _when processing CLI arguments_. `cmd.exe` ignores the `\ ` itself, though its treating the following `"` as a syntax element then brings its own challenges. — mklement0, Nov 14 '18 at 19:07

mklement0 · Accepted Answer · 2018-11-14T20:23:29.987

You must escape the nested " chars. in your command, which is most robustly done as \"" (sic):

PowerShell.exe -c  "Get-WmiObject -Query \""Select * ... 'ost'\"" | Select ..."

Caveat: Use of \"" works well and robustly with powershell.exe, (and pwsh for PowerShell Core) but not with other programs, such as python, ruby, perl or node.

See the linked answer for a detailed explanation, including how to escape for other programs.

Running PowerShell command from CMD gives positional parameter error

1 Answers1