Function New-RandomFileName {

[cmdletbinding(DefaultParameterSetName = "none")]

[Alias("rfn")]

[outputtype([string])]

Param(

[parameter(Position = 0)]

[Parameter(ParameterSetName = 'none')]

[Parameter(ParameterSetName = 'home')]

[Parameter(ParameterSetName = 'temp')]

#enter an extension without the leading period e.g 'bak'

[string]$Extension,

[Parameter(ParameterSetName = 'temp')]

[alias("temp")]

[Switch]$UseTempFolder,

[Parameter(ParameterSetName = 'home')]

[alias("home")]

[Switch]$UseHomeFolder

)

if ($UseTempFolder) {

$filename = [system.io.path]::GetTempFileName()

}

elseif ($UseHomeFolder) {

$homedocs =[Environment]::GetFolderPath([Environment+SpecialFolder]::MyDocuments)

$filename = Join-Path -Path $homedocs -ChildPath ([system.io.path]::GetRandomFileName())

}

else {

$filename = [system.io.path]::GetRandomFileName()

}

if ($Extension) {

#get the extension and strip off the leading period

$original = [system.io.path]::GetExtension($filename).Substring(1)

$filename -replace "$original$", $Extension

}

else {

$filename

}

} #end New-RandomFilename

Function New-CustomFileName {

[cmdletbinding()]

[Alias("cfn")]

[outputtype([string])]

Param (

[Parameter(

Position = 0,

Mandatory,

HelpMessage = @"

You can create a template string using any of these variables, including the % symbol.

- %username

- %computername

- %year - 4 digit year

- %yr - 2 digit year

- %monthname - The abbreviated month name

- %month - The month number

- %dayofweek - The full name of the week day

- %day

- %hour - the hour of the day in 12 hour format to 2 digits

- %hour24 - the hour of the day in 24 hour format to 2 digits

- %minute

- %seconds

- %time - A compact string of HourMinuteSecond

- %string - A random string

- %guid

- %### - a random number matching the number of # characters

"@)]

[ValidateNotNullOrEmpty()]

[string]$Template,

[ValidateSet("Lower", "Upper", "Default")]

[string]$Case = "Default"

)

#convert placeholders to lower case but leave everything else as is

[regex]$rx = "%\w+(?=%|-|\.|\s|\(|\)|\[|\])"

Write-Detail "Starting $($myinvocation.MyCommand)" | Write-Verbose

Write-Detail "Processing template: $template" | Write-Verbose

$rx.matches($Template) | ForEach-Object {

Write-Detail "Converting $($_.value) to lower case" | Write-Verbose

$Template = $Template.replace($_.value, $_.value.tolower())

}

[string]$filename = $Template

Write-Detail "Using filename: $filename" | Write-Verbose

$now = Get-Date

if ($env:USERNAME) {

$user = $env:USERNAME

}

elseif ($env:USER) {

$user = $env:USER

}

else {

$user = "Unknown"

}

#this needs to be an ordered hashtable so that the regex replacements

#will be processed in the right order

$hash = [ordered]@{

'%username' = $user

'%computername' = [environment]::MachineName

'%year' = $now.Year

'%yr' = "{0:yy}" -f $now

'%monthname' = ("{0:MMM}" -f $now)

'%month' = "{0:MM}" -f $now

'%dayofweek' = $now.DayOfWeek

'%day' = "{0:dd}" -f $now

'%hour24' = "{0:HH}" -f $now

'%hour' = "{0:hh}" -f $now

'%minute' = "{0:mm}" -f $now

'%seconds' = "{0:ss}" -f $now

'%time' = "{0}{1}{2}" -f $now.hour, $now.minute, $now.Second

'%string' = ([system.io.path]::GetRandomFileName()).split(".")[0]

'%guid' = [System.Guid]::NewGuid().guid

}

$hash.GetEnumerator() | ForEach-Object {

Write-Detail "Testing $filename for $($_.key)" | Write-Verbose

if ($filename -match "($($_.key))") {

Write-Detail "replacing $($_.key) with $($_.value)" | Write-Verbose

$filename = $filename -replace "($($_.key))", $_.value

}

}

#handle ### number replacement

[regex]$rx = '%#+'

if ($rx.IsMatch($filename)) {

$count = $rx.Match($filename).Value.length - 1

$num = (0..9 | Get-Random -Count 10 | Get-Random -count $count) -join ""

Write-Detail "replacing # with $num" | Write-Verbose

$filename = $rx.Replace($filename, $num)

}

Write-Detail "Converting case to $Case" | Write-Verbose

Switch ($Case) {

"Upper" {

$filename.toUpper()

}

"Lower" {

$filename.ToLower()

}

default {

$filename

}

} #close switch

Write-Detail "Ending $($myinvocation.MyCommand)" | Write-Verbose

} #end New-CustomFileName