PowerShell and Ampersand

I have the following simple Powershell script:

$test = "Test%$&*()!@#&"

Write-Host  "$test" 
C:\Temp\Test.cmd $test

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ECHO Parameter = %1

PS H:\> $test = "Test%$&*()!@#&"

Write-Host  "$test"
C:\Temp\Test.cmd $test


H:\>ECHO Parameter = Test%$
Parameter = Test%$
Test.cmd : '*' is not recognized as an internal or external command,
At line:6 char:1
+ C:\Temp\Test.cmd $test
+ ~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: ('*' is not reco...ternal command,:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
operable program or batch file.

PS H:\>
LVL 96
Bob LearnedAsked:
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I don't think this is anything to do with PowerShell.
At a command prompt (not PS), try running
test.cmd Test%$&*()!@#&

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and you see the error.  I'd say it's a limitation of the command processor, but that's just a guess.
You might need to escape the & character.  My first thought would be to try the backslash or carrot character to do the escape.

Otherwise, you might try putting the string in quotes.
Qlemo"Batchelor", Developer and EE Topic AdvisorCommented:
I too thought it to be a cmd issue, but the error message looks like it is generated by PowerShell, not cmd.exe, and that puzzled me. However, it is indeed cmd.exe.
The command is expanded to be
C:\Temp\Test.cmd Test%$&*()!@#&

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in PowerShell. Though you may not use that line directly in PowerShell (the ampersand is an reserved operator, and may not be used literally outside of a string), it is valid if using a string var.
Now, because cmd.exe is the registered app for .cmd files, it is triggered and starts interpreting the command line. It sees
C:\Temp\Test.cmd Test%$ & *()!@# &

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because ampersand is a command separator (like semi-colon in PowerShell), used for concatenating commands, like in
echo one & echo two

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The batch file runs fine, but then a command starting with * is tried to be run - to no avail, of course. Even if that would succeed, the trailing ampersand would cause an error, as no further command is following it.
You wiill have issues with parens, caret, ampersand and potentially percent and exclamation mark if trying to pass to a batch file. As long as there is no double quote involved, this should work in PowerShell
C:\Temp\Test.cmd """$test"""

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but the double quotes are then part of the parameter:
Parameter = "Test%$&*()!@#&"

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This again can be compensated by using %~1, but that again opens another can of worms with the same result - an error message because of the ampersand, but this time from within the batch file.

Base line: You are f*cked up if you need to call .cmd files with parameters or environment vars containing some special characters. I can tell you a thing or two about it - trying to pass passwords that way can be pain.

My recommendation is to stay within PowerShell. Mixing PS and VBS is ok (if necessary), but never call .cmd files; the mix makes it just more difficult to maintain and troubleshoot.

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Bob LearnedAuthor Commented:
It was the triple double-quotes that fixed my problem:

C:\Temp\Test.cmd """$test"""
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