PowerShell Switch Parameter

One of the things that I’ve noticed in the PowerShell cmdlets are parameters without values.  These switches alter the way that the cmdlet functions without providing any input.  This is the switch parameter functionality.  Here is how it works. 

When you declare a parameter as a switch parameter, its value is set to $False.  Using what ever logic you like, you can test to see if the condition became $True.  That means the user executed the function and specified the switch.  Let’s look at a simple example:

function Test1 ([Int32]$Value,[switch]$Add5){
if ($Add5 -eq $True) {$Value += 5}
Write-Host $Value
}

In the function Test1, we have two values, a number and the switch parameter called $Add5.  This function is simple.  You provide it a number and it displays the number.  If you add the –Add5 parameter, it adds 5 to the number you provided.  Here is an example:

PS C:\Users\Jason> test1 5

5


PS C:\Users\Jason>

In the above example, we executed the script with the value of 5.  The result was 5.

PS C:\Users\Jason> test1 5 -Add5

10


PS C:\Users\Jason>

In this example, we included the –Add5 switch parameter.  In our code, we stipulated that if this parameter is $True, the we add 5 to the $Value that we gave the function.





The switch parameter functionality is good to use when you need to have a Boolean value as a parameter.