PowerShell Function Example with input validation

PowerShell_function_with_input_validation.ps1

<#
Nicholas Leader
05/16/2016
Simple function example
In this example I'm showing how input to the function can be validated

After running this script a 'Test-name' function will be available, which accepts an argument or parameter

Reference: http://mikefrobbins.com/2015/03/31/powershell-advanced-functions-can-we-build-them-better-with-parameter-validation-yes-we-can/

#>

# declaring the function name
function Test-name {

# binding to a cmdlet for calling function after script is run
    [CmdletBinding()]
  
# setting up the parameter or argument to the function  
    param (
        [ValidateScript({


# filting the input - if the user's value contains 'Monkey' or 'test' in the string, then the function will return
            If ($_ -like '*Monkey*'-or $_ -like '*test*') {
                $True
            }

# if 'monkey' or 'test' are not in the string supplied by the user then an error is thrown

            else {
                Throw "$_ is either not a valid filename or it is not recommended."
            }
        })]

# Setting the function object to a string
        [string]$FileName
    )

# writing the output of the function (assuming the value is bool of true) to the console
    Write-host $FileName "is acceptable!"