Basic Template for writing a PS script

PSTemplate.ps1

<#
.SYNOPSIS
  <Overview of script>

.DESCRIPTION
  <Brief description of script>

.PARAMETER <Parameter_Name>
    <Brief description of parameter input required. Repeat this attribute if required>

.INPUTS
  <Inputs if any, otherwise state None>

.OUTPUTS
  <Outputs if any, otherwise state None - example: Log file stored in C:\Windows\Temp\<name>.log>

.NOTES
  Version:        1.0
  Author:         Your Name
  Creation Date:  <Date>
  Purpose/Change: Initial script development
  
.EXAMPLE
  <Example goes here. Repeat this attribute for more than one example>
#>


#----------------------------------------------------------[Declarations]----------------------------------------------------------

#Parameters
[CmdletBinding()]
Param(
  [Parameter(Mandatory=$false,Position=1)] # Non-mandatory String type parameter with a default value of "one" in the 1st position
   [string]$stringparameter="one",
	
   [Parameter(Mandatory=$false)] # Non-mandatory integer type parameter with a default value of 2
   [int]$integerparameter=2,

   [Parameter(Mandatory=$false)] # Non-mandatory array type parameter with a default values of [0]=10,[1]=20,[2]=30
   [array]$arrayparameter=@(10,20,30),

   [Parameter(Mandatory=$false)] # Non-mandatory boolean type parameter with a default value of TRUE
   [bool]$booleanparameter=$True
)

#---------------------------------------------------------[Initialisations & Functions]--------------------------------------------------------

#Set Error Action to Silently Continue
$ErrorActionPreference = "SilentlyContinue"

#Dot Source required Function Libraries
# . "C:\Scripts\Functions\Logging_Functions.ps1"

$ArrayCollection = @() # Define and reset the Array
$ArrayObject = "" | Select-Object 1stattr, 2ndattr, 3rdattr # Variable Attributes
$ArrayCollection += $ArrayObject # Build Array

Function Write-Log {
  <#
      .Synopsis
          Write-Log writes a message to a specified log file with the current time stamp.
      .DESCRIPTION
          The Write-Log function is designed to add logging capability to other scripts.
          In addition to writing output and/or verbose you can write to a log file for
          later debugging.
      .NOTES
          Created by: Jason Wasser @wasserja
          Modified: 11/24/2015 09:30:19 AM  

          Changelog:
              * Code simplification and clarification - thanks to @juneb_get_help
              * Added documentation.
              * Renamed LogPath parameter to Path to keep it standard - thanks to @JeffHicks
              * Revised the Force switch to work as it should - thanks to @JeffHicks

          To Do:
              * Add error handling if trying to create a log file in a inaccessible location.
              * Add ability to write $Message to $Verbose or $Error pipelines to eliminate
              duplicates.
      .PARAMETER Message
          Message is the content that you wish to add to the log file. 
      .PARAMETER Path
          The path to the log file to which you would like to write. By default the function will 
          create the path and file if it does not exist. 
      .PARAMETER Level
          Specify the criticality of the log information being written to the log (i.e. Error, Warning, Informational)
      .PARAMETER NoClobber
          Use NoClobber if you do not wish to overwrite an existing file.
      .EXAMPLE
          Write-Log -Message 'Log message' 
          Writes the message to c:\Logs\PowerShellLog.log.
      .EXAMPLE
          Write-Log -Message 'Restarting Server.' -Path c:\Logs\Scriptoutput.log
          Writes the content to the specified log file and creates the path and file specified. 
      .EXAMPLE
          Write-Log -Message 'Folder does not exist.' -Path c:\Logs\Script.log -Level Error
          Writes the message to the specified log file as an error message, and writes the message to the error pipeline.
      .LINK
          https://gallery.technet.microsoft.com/scriptcenter/Write-Log-PowerShell-999c32d0
  #>

  [CmdletBinding()]
  Param
  (
      [Parameter(Mandatory = $true,
          ValueFromPipelineByPropertyName = $true)]
      [ValidateNotNullOrEmpty()]
      [Alias("LogContent")]
      [string]$Message,

      [Parameter(Mandatory = $false)]
      [Alias('LogPath')]
      [string]$Path = 'C:\Logs\PowerShellLog.log',
      
      [Parameter(Mandatory = $false)]
      [ValidateSet("Error", "Warn", "Info")]
      [string]$Level = "Info",
      
      [Parameter(Mandatory = $false)]
      [switch]$NoClobber
  )

  Begin {
      # Set VerbosePreference to Continue so that verbose messages are displayed.
      $VerbosePreference = 'Continue'
  }
  Process {
      
      # If the file already exists and NoClobber was specified, do not write to the log.
      if ((Test-Path $Path) -AND $NoClobber) {
          Write-Error "Log file $Path already exists, and you specified NoClobber. Either delete the file or specify a different name."
          Return
      }

      # If attempting to write to a log file in a folder/path that doesn't exist create the file including the path.
      elseif (!(Test-Path $Path)) {
          Write-Verbose "Creating $Path."
          $NewLogFile = New-Item $Path -Force -ItemType File
      }

      else {
          # Nothing to see here yet.
      }

      # Format Date for our Log File
      $FormattedDate = Get-Date -Format "yyyy-MM-dd HH:mm:ss"

      # Write message to error, warning, or verbose pipeline and specify $LevelText
      switch ($Level) {
          'Error' {
              Write-Error $Message
              $LevelText = 'ERROR:'
          }
          'Warn' {
              Write-Warning $Message
              $LevelText = 'WARNING:'
          }
          'Info' {
              Write-Verbose $Message
              $LevelText = 'INFO:'
          }
      }
      
      # Write log entry to $Path
      "$FormattedDate $LevelText $Message" | Out-File -FilePath $Path -Append
  }
  End {
  }
}

#-----------------------------------------------------------[Execution]------------------------------------------------------------

Set-ExecutionPolicy -ExecutionPolicy Unrestricted -Force

#Script Execution goes here

Write-Log -Message "Starting Log"