How to evaluate PowerShell script inputed from stdin

Question

I want to evaluate the content from StdIn in PowerShell, like this:

echo "echo 12;" | powershell -noprofile -noninteractive -command "$input | iex"

Output:

echo 12;

Unfortunately, $input is not a String, but a System.Management.Automation.Internal.ObjectReader, which make iex not working as expected... since this one is working correctly:

powershell -noprofile -noninteractive -command "$command = \"echo 12;\"; $command | iex"

Output:

12

Answer 1

The following would work:

Use a scriptblock:

echo "echo 12;" | powershell -noprofile -noninteractive -command { $input | iex }

Or use single quotes to avoid the string interpolation:

 echo "echo 12;" | powershell -noprofile -noninteractive -command '$input | iex'

so the $input variable isn't expanded, and the string '$input' is passed to iex.

Both of these give me "12".

Answer 2

Just use - as a source file "name":

echo "echo 12;" | powershell -noprofile -noninteractive -