How to pass command-line arguments to a PowerShell ps1 file

For years, I have used the cmd/DOS/Windows shell and passed command-line arguments to batch files. For example, I have a file, zuzu.bat and in it, I access %1, %2, etc. Now, I want to do the same when I call a PowerShell script when I am in a Cmd.exe shell. I have a script, xuxu.ps1 (and I've added PS1 to my PATHEXT variable and associated PS1 files with PowerShell). But no matter what I do, I seem unable to get anything from the $args variable. It always has length 0.

If I am in a PowerShell shell, instead of cmd.exe, it works (of course). But I'm not yet comfortable enough to live in the PowerShell environment full time. I don't want to type powershell.exe -command xuxu.ps1 p1 p2 p3 p4. I want to type xuxu p1 p2 p3 p4.

Is this possible, and if so, how?

The sample I cannot get to work is trivial, foo.ps1:

Write-Host "Num Args:" $args.Length;
foreach ($arg in $args) {
    Write-Host "Arg: $arg";
}

The results are always like this:

C:\temp> foo
Num Args: 0
C:\temp> foo a b c d
Num Args: 0
c:\temp>

This article helps. In particular, this section:

-File

Runs the specified script in the local scope ("dot-sourced"), so that the functions and variables that the script creates are available in the current session. Enter the script file path and any parameters. File must be the last parameter in the command, because all characters typed after the File parameter name are interpreted as the script file path followed by the script parameters.

i.e.

powershell.exe -File "C:\myfile.ps1" arg1 arg2 arg3

means run the file myfile.ps1 and arg1 arg2 & arg3 are the parameters for the PowerShell script.

After digging through the PowerShell documentation, I discovered some useful information about this issue. You can't use the $args if you used the param(...) at the beginning of your file; instead you will need to use $PSBoundParameters. I copy/pasted your code into a PowerShell script, and it worked as you'd expect in PowerShell version 2 (I am not sure what version you were on when you ran into this issue).

If you are using $PSBoundParameters (and this ONLY works if you are using param(...) at the beginning of your script), then it is not an array, it is a hash table, so you will need to reference it using the key / value pair.

param($p1, $p2, $p3, $p4)
$Script:args=""
write-host "Num Args: " $PSBoundParameters.Keys.Count
foreach ($key in $PSBoundParameters.keys) {
    $Script:args+= "`$$key=" + $PSBoundParameters["$key"] + "  "
}
write-host $Script:args

And when called with...

PS> ./foo.ps1 a b c d

The result is...

Num Args:  4
$p1=a  $p2=b  $p3=c  $p4=d

OK, so first this is breaking a basic security feature in PowerShell. With that understanding, here is how you can do it:

1. Open an Windows Explorer window
2. Menu Tools -> Folder Options -> tab File Types
3. Find the PS1 file type and click the advanced button
4. Click the New button
5. For Action put: Open
6. For the Application put: "C:\WINNT\system32\WindowsPowerShell\v1.0\powershell.exe" "-file" "%1" %*

You may want to put a -NoProfile argument in there too depending on what your profile does.

You could declare your parameters in the file, like param:

[string]$para1
[string]$param2

And then call the PowerShell file like so .\temp.ps1 para1 para2....para10, etc.

Maybe you can wrap the PowerShell invocation in a .bat file like so:

rem ps.bat
@echo off
powershell.exe -command "%*"

If you then placed this file under a folder in your PATH, you could call PowerShell scripts like this:

ps foo 1 2 3

Quoting can get a little messy, though:

ps write-host """hello from cmd!""" -foregroundcolor green