MD5 Hash function

Had to get the MD5 Hash on some files and needed a light weight script. So here it is:

function Get-Md5Hash
{
    <#
        .SYNOPSIS
        This function returns the Md5 Hash for a given file.
 
        .DESCRIPTION
        This function returns the Md5 Hash for a given file.
        You can Pipe in files or just use one at a time.
 

        .EXAMPLE
        PS C:\> $ReturnedHash = Get-Md5Hash "c:\test\MyFile.txt"
 
        .EXAMPLE
        PS C:\> @("C:\TEST\TestFile1.txt","C:\TEST\TestFile2.txt","C:\TEST\TestFile3.txt") | Get-Md5Hash
 
        .INPUTS
        A file name/location.
 
        .OUTPUTS
        The Md5 Hash of the given file is returned.
 
        .NOTES
        Function Name: Get-Md5Hash
        Original Author: Norman Skinner (normans)
        Original Created on: 09/26/2013
        Version: 1.0.0.0
 
        HISTORY:
        ===========#==============#======================================
        Date       | User         | Description
        -----------+--------------+--------------------------------------
        09/26/2013 | normans      | Created script
        -----------+--------------+--------------------------------------
                   |              | 
        -----------+--------------+--------------------------------------
                   |              | 
        -----------+--------------+--------------------------------------
    #>
 
    param
    (
        [parameter(Mandatory=$true,ValueFromPipeline=$true)]
        [string]
        # This the file for getting the Md5 hash.
        $File
    )
    PROCESS
    {
        $MD5object = new-object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
        $Md5Hash   = [System.BitConverter]::ToString($MD5object.ComputeHash([System.IO.File]::ReadAllBytes($File)))
        return $Md5Hash
    }
}

Check if Running As Administrator

Have you ever had a script that requires it be run in “Run As Administrator” mode and needed a function to check that? When I run into this I use the following function:

function Confirm-RunningAsAdministrator
{
<# 
.SYNOPSIS 
This function will return a bool, "True" if running as administrator,
"False" if not.
  
.DESCRIPTION 
You can use this script to check is you are currently running as
administrator. It is best used when your script needs to verify
that this is the case.
  
.EXAMPLE 
    if (Confirm-RunningAsAdministrator)
    {
        Write-Host "Running as an administrator."
    }
    else
    {
        Write-Host "NOT running as an administrator."
    }

    ----------------------------------------------------------- 
    If running as an administrator, this would produce: 
      
Running as an administrator. 
  
.INPUTS 
None. 
  
.OUTPUTS 
[bool] - "True" if running as administrator, "False" if not. 
  
.NOTES 
Original Function name: Confirm-RunningAsAdministrator.ps1 
Original Author: Norman Skinner 
Original Created on: 12/05/2012 

HISTORY:
    ===========#================#=========#============================
    Date       | User           | Version | Description
    -----------+----------------+---------+----------------------------
    12/05/2011 | Norman Skinner | 1.0.0.0 | Created script
    -----------+----------------+---------+----------------------------
               |                |         |
    -----------+----------------+---------+----------------------------
#> 
    $WinIdentity = [Security.Principal.WindowsIdentity]::GetCurrent()
    $currentPrincipal = New-Object Security.Principal.WindowsPrincipal($WinIdentity)
    $AdministratorRole =  [Security.Principal.WindowsBuiltInRole]::Administrator 
    return $currentPrincipal.IsInRole($AdministratorRole)
}

Write-NoteStart

Once in a while I have to output information from a script that will say what I am doing and then if it completed or failed. In most cases it would look horrible on the screen. Like so:

Checking network connection...completed.
Checking file...completed.
Writing network information to file...completed.

This bugged me to no end; so I wrote the “Write-NoteStart” function to make it easier for me to sleep at night. When using this function the output looks more like this:

Checking network connection.............completed.
Checking file...........................completed.
Writing network information to file.....completed.

Here is the function:

function Write-NoteStart
{
<#
.SYNOPSIS
This function will place periods after writing a string and not write a new line.

.DESCRIPTION
This script is used to produce dots/periods after a given string for aligning
results. You can adjust the position it should add dots up to.

.EXAMPLE
    Write-NoteStart "Checking status" -DotTo 40
    Write-Host "completed."
    Write-NoteStart "Checking your connection" -DotTo 40
    Write-Host "completed."
    -----------------------------------------------------------
    This would produce:
    
Checking status.........................completed.
Checking your connection................completed.

.INPUTS
A string and an int.


.OUTPUTS
Write-Host to the screen with your string followed by periods.

.NOTES
Original Function name: Write-NoteStart.ps1
Original Author: Norman Skinner
Original Created on: 02/01/2012
Version: 1.0.0.0

#>
    param (
        [string]
        # The string for the start of the line.
        $Note = "No data",
        [int]
        # What line position to run dots to.
        $DotTo = 60
    )
    if ($Note.Length -lt $DotTo)
    {
        Write-Host $Note -NoNewline
        for ($i = $Note.Length;$i -lt $DotTo; $i++)
        {
            Write-Host "." -NoNewline
        }
    }
    else
    {
        Write-Host $Note
    }
}

PowerShell: Try, Catch, and Finally

This is the example I like to refer to for my PowerShell try/catch/finally blocks. 

###---------------------------------------------
### A try/catch/finally example.
###---------------------------------------------
try
{
    Write-Host "Try this."
    $Result = 1/$Zero
}
catch [System.DivideByZeroException]
{
    Write-Host "Caught divid by zero exception."
}

catch [System.SystemException]
{
    # This catch will catch every thing else.
    Write-Host "Caught base exception."
}
finally
{
    Write-Host "Finally this."
}