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

In PowerShell, boolean parameters can be declared by mentioning their type before their variable.

    function GetWeb() {
             param([bool] $includeTags)
    ........
    ........
    }

You can assign value by passing $true | $false

    GetWeb -includeTags $true

Answer 2

To summarize and complement the existing answers, as of Windows PowerShell v5.1 / PowerShell Core 7.0.0-preview.4:

David Mohundro's answer rightfully points that instead of [bool] parameters you should use [switch] parameters in PowerShell, where the presence vs. absence of the switch name (-Unify specified vs. not specified) implies its value, which makes the original problem go away.

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However, on occasion you may still need to pass the switch value explicitly, particularly if you're constructing a command line programmatically:

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In PowerShell Core, the original problem (described in Emperor XLII's answer) has been fixed.

That is, to pass $true explicitly to a [switch] parameter named -Unify you can now write:

pwsh -File .\RunScript.ps1 -Unify:$true  # !! ":" separates name and value, no space

The following values can be used: $false, false, $true, true, but note that passing 0 or 1 does not work.

Note how the switch name is separated from the value with : and there must be no whitespace between the two.

^{Note: If you declare a [bool] parameter instead of a [switch] (which you generally shouldn't), you must use the same syntax; even though -Unify $false should work, it currently doesn't - see this GitHub issue.}

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In Windows PowerShell, the original problem persists, and - given that Windows PowerShell is no longer actively developed - is unlikely to get fixed.

• The workaround suggested in LarsWA's answer - even though it is based on the official help topic as of this writing - does not work in v5.1

  • This GitHub issue asks for the documentation to be corrected and also provides a test command that shows the ineffectiveness of the workaround.

• Using -Command instead of -File is the only effective workaround:

:: # From cmd.exe
powershell -Command "& .\RunScript.ps1 -Unify:$true" 

With -Command you're effectively passing a piece of PowerShell code, which is then evaluated as usual - and inside PowerShell passing $true and $false works (but not true and false, as now also accepted with -File).

Caveats:

• Using -Command can result in additional interpretation of your arguments, such as if they contain $ chars. (with -File, arguments are literals).

• Using -Command can result in a different exit code.

For details, see this answer and this answer.

Answer 3

I think, best way to use/set boolean value as parameter is to use in your PS script it like this:

Param(
    [Parameter(Mandatory=$false)][ValidateSet("true", "false")][string]$deployApp="false"   
)

$deployAppBool = $false
switch($deployPmCmParse.ToLower()) {
    "true" { $deployAppBool = $true }
    default { $deployAppBool = $false }
}

So now you can use it like this:

.\myApp.ps1 -deployAppBool True
.\myApp.ps1 -deployAppBool TRUE
.\myApp.ps1 -deployAppBool true
.\myApp.ps1 -deployAppBool "true"
.\myApp.ps1 -deployAppBool false
#and etc...

So in arguments from cmd you can pass boolean value as simple string :).

Answer 4

I had something similar when passing a script to a function with invoke-command. I ran the command in single quotes instead of double quotes, because it then becomes a string literal. 'Set-Mailbox $sourceUser -LitigationHoldEnabled $false -ElcProcessingDisabled $true';

Answer 5

You can also use 0 for False or 1 for True. It actually suggests that in the error message:

Cannot process argument transformation on parameter 'Unify'. 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.

For more info, check out this MSDN article on Boolean Values and Operators.

Answer 6

Try setting the type of your parameter to [bool]:

param
(
    [int]$Turn = 0
    [bool]$Unity = $false
)

switch ($Unity)
{
    $true { "That was true."; break }
    default { "Whatever it was, it wasn't true."; break }
}

This example defaults $Unity to $false if no input is provided.

Usage

.\RunScript.ps1 -Turn 1 -Unity $false