Why won't this powershell script accept parameters?

Question

myscript.ps1

Param(
    [Parameter(Mandatory=$true,Position=1)]
    [string]$computerName
)

echo "arg0: " $computerName

CMD.exe

C:\> myscript.ps1 -computerName hey

Output:

    cmdlet myscript.ps1 at command pipeline position 1
    Supply values for the following parameters:
    computerName: ddd
    arg0:
    ddd

I'm simply trying to work with Powershell parameters in CMD, and I can't seem to get a script to take one. I see sites saying to precede the script with .\ but that doesn't help. I added the mandatory line to see if Powershell was reading a parameter or not, and it's clearly not. The parameter computerName is obviously the word "hey". The Param block is the very first thing in the script. Powershell appears to recognize a parameter computerName, but no matter how I enter the command, it never thinks I'm actually entering parameter.

What the heck's wrong with my syntax?

Your code clearly works fine on my machine Seven with PowerShell 2.0. What is your installation of Powershell (OS ? PS version ?) — JPBlanc
– JPBlanc, Commented Sep 26, 2012 at 3:23
Yea this looks fine and should work. How exactly are you calling the script? From powershell.exe? From FSI? With a full path, with a relative path? — latkin
– latkin, Commented Sep 26, 2012 at 19:49
Oh man... I was calling it from CMD. My question was slightly edited, actually. See my answer below. Thank you very much for your responses, though. — Spencer Williams
– Spencer Williams, Commented Sep 26, 2012 at 22:28

Darin Strait · Accepted Answer · 2012-09-26 13:48:01Z

By default, Powershell will not run scripts that it just happens to find in your current directory. This is intended by Microsoft as a security feature, and I believe that it mimics behavior found in unix shells.

Powershell will run scripts that it finds in your search path. Your search path is stored in $env:path.

I suspect that you have a script named "myscript.ps1" in some other directory that is on your search path.

I have had this happen to me before. The symptom I saw was that the parameter list seemed different than what I had defined. Each script had a different parameter list, so the script bombed when I fed it a parameter list intended for the other script. My habit is to not rely on parameter position, so this problem was easy to find.

The addition of ".\" to the script ".\myscript.ps1" should force the shell to use the .ps1 file in your current directory. As a test, I would specify the full path to the file you are trying to execute (If there are spaces in the path, be sure to wrap the path in "quotes") or change it to some totally crazy name that won't be duplicated by some other file (like "crazyfishpants.ps1") and see if the shell still finds the file.

You can get into similar problems if you have a function ("Get-Foo") that is loaded out of a module or profile with the same name as a script file ("Get-Foo.ps1"). You may wind up running something other than what you intend.

Keith Hill · Accepted Answer · 2012-09-26 05:28:29Z

1

Position values should be 0-based (0 for the first parameter). That said, I can't duplicate what you're seeing on either PowerShell 2.0 or 3.0.

answered Sep 26, 2012 at 5:28

Keith Hill

204k44 gold badges370 silver badges377 bronze badges

Comments

Spencer Williams · Accepted Answer · 2012-09-26 22:26:38Z

Thank you all for your very informative responses. It looks like my question was slightly edited before I submitted it, in that the text leads you to believe that I was entering this command directly in Powershell.

I was actually running the command for the script in CMD, which totally explains why it was not passing parameters to the Powershell script. Whoever green-lighted my question probably changed C:\> to PS> thinking that I made a typo.

I assumed that if I could run the script straight from CMD, I could send parameters to it on CMD's command line, but apparently that's not the case. If I run the script in Powershell, it indeed works just fine, I'm now seeing.

My ultimate goal was to allow users to run the Powershell script from CMD. It's looking like I can make a batch file that accepts parameters, and then start powershell and send those parameters to the PS script. And so, in the batch file, I should do something like:

powershell -File C:\myscript.ps -computerName %1

This enigma was probably solved 100 times over on this site, and I apologize for the confusion. Thank you again, for your responses.

Collectives™ on Stack Overflow

Why won't this powershell script accept parameters?

myscript.ps1

CMD.exe

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

myscript.ps1

CMD.exe

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related