Newbie powershell argument issues

Question

I made powershell script that [1] accepts 2 arguments (aka parameters), [2] changes a file's modified date & time, and [3] writes something to host. The following command line works just fine in the powershell console, but triggers an error message when I run the same command line in a Windows cmd prompt (DOS) Window:

E:\Apps\UtilitiesByMarc\Change_DateTime_for_test1.bat_and_Hello_world_with_2_named_args_aaa.ps1 -dateTimeVarArg "01/11/2005 06:01:36" -file_dateTimeMod_fullname "E:\Apps\Delete01\test1.bat"

The following is the coding for the powershell script to which I gave the long name, 'Change_DateTime_for_test1.bat_and_Hello_world_with_2_named_args_aaa.ps1':

param ( [string]$dateTimeVarArg,  [string]$file_dateTimeMod_fullname)
Get-ChildItem  $file_dateTimeMod_fullname | % {$_.LastWriteTime = $dateTimeVarArg}
#Get-ChildItem  "E:\Apps\Delete01\test1.bat" | % {$_.LastWriteTime = $dateTimeVarArg}
$strString = "Hello World"
write-host $strString


function ftest{
$test = "Test"
write-host $test
}

ftest

When I run the command line shown above in a Windows DOS command prompt setting, I get the following error message:

Exception setting "LastWriteTime": "Cannot convert null to type "System.DateTime"."
At E:\Apps\UtilitiesByMarc\Change_DateTime_for_test1.bat_and_Hello_world_with_1_named_arg_aaa.ps1:6 char:50
+ ... "E:\Apps\Delete01\test1.bat" | % {$_.LastWriteTime = $dateTimeVarArg}
+                                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], SetValueInvocationException
    + FullyQualifiedErrorId : ExceptionWhenSetting

I would like to know [1] how to alter the command line shown above (which works fine in the powershell console) so that it works in a Windows DOS command prompt setting, and [2] where I can learn more about why my command line triggers errors, and how to avoid them.
According to the output from the command "Get-Host | Select-Object Version", I am running version. 5.1.19041.1682.

Any tips would be much appreciated.

Answer 1

By default, you can not directly execute PowerShell scripts (.ps1 files) from cmd.exe, the Windows legacy shell, or from outside PowerShell altogether.

• Attempting to do so opens the script file for editing instead, as does double-clicking .ps1 files from File Explorer / the desktop.

Executing .ps1 scripts from outside PowerShell itself requires use of the PowerShell CLI (powershell.exe for Windows PowerShell, pwsh for PowerShell (Core) 7+), which in your case translates to a call such as (additional CLI parameters may be called for):

powershell.exe -File E:\Apps\UtilitiesByMarc\Change_DateTime_for_test1.bat_and_Hello_world_with_2_named_args_aaa.ps1 -dateTimeVarArg "01/11/2005 06:01:36" -file_dateTimeMod_fullname "E:\Apps\Delete01\test1.bat"

---

As for what you tried:

The fact that you were able to execute your .ps1 from cmd.exe suggests that you changed the file-type definition for such files to execute via powershell.exe instead.

The fact that the arguments you tried to pass to the script were ignored - as implied by the error message you got - suggests that you used File Explorer's Open with shortcut-menu command to choose to open all .ps1 files with powershell.exe; said method does not support argument-passing.

There is a way to change the file-type definition to support argument-passing too, and it is detailed in this answer (section "Programmatic method").

Generally, however, I suggest not applying this customization, especially in batch files that must also be run by other users / on other machines, which cannot be expected to have the same customization in place.