How to pass boolean values to a PowerShell script from a command prompt

Question

I have to invoke a PowerShell script from a batch file. One of the arguments to the script is a boolean value:

C:\\Windows\\System32\\WindowsPowerShell\\v1.0         


        

Answer 1

It appears that powershell.exe does not fully evaluate script arguments when the -File parameter is used. In particular, the $false argument is being treated as a string value, in a similar way to the example below:

PS> function f( [bool]$b ) { $b }; f -b '$false'
f : Cannot process argument transformation on parameter 'b'. Cannot convert value 
"System.String" to type "System.Boolean", parameters of this type only accept 
booleans or numbers, use $true, $false, 1 or 0 instead.
At line:1 char:36
+ function f( [bool]$b ) { $b }; f -b <<<<  '$false'
    + CategoryInfo          : InvalidData: (:) [f], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : ParameterArgumentTransformationError,f

Instead of using -File you could try -Command, which will evaluate the call as script:

CMD> powershell.exe -NoProfile -Command .\RunScript.ps1 -Turn 1 -Unify $false
Turn: 1
Unify: False

As David suggests, using a switch argument would also be more idiomatic, simplifying the call by removing the need to pass a boolean value explicitly:

CMD> powershell.exe -NoProfile -File .\RunScript.ps1 -Turn 1 -Unify
Turn: 1
Unify: True