Get hash values of files as a batch job (multiple files at once)

HashGroup.ps1

<#
  .SYNOPSIS
    Hashes all files in a directory and sub-directories.
  .DESCRIPTION
    Hashes all files in a directory and sub-directories.
  .PARAMETER Path
    Path to the directory to hash.
  .PARAMETER Algorithm
    Select hash algorithm.
  .EXAMPLE
    HashGroup.ps1 -Path C:\Users\User\Documents
    HashGroup.ps1 -Path C:\Users\User\Documents -Algotithm MD5
  .NOTES
    Author: neuralpain
    Date created: 2024-06-26
    Last modified: 2024-06-30

    Version history:
      0.1.0 - Initial hash function
      0.2.0 - Allow user to select a specific hashing algorithm
#>

[CmdletBinding()]
Param(
  [Parameter(Mandatory = $false)]
  [string]$Path = $pwd,
  [Parameter(Mandatory = $false)]
  [string]$Algorithm
)

$HashMD5 = 'NULL'
$HashSHA1 = 'NULL'
$HashSHA256 = 'NULL'
$HashSHA512 = 'NULL'

# clean up and reset
if (Test-Path "$Path\#HashGroup") { Remove-Item "$Path\#HashGroup\*" -Force -Recurse }
else { New-Item -Path $Path -Name "#HashGroup" -ItemType Directory | Out-Null }

# get files
$Files = Get-ChildItem -Path $Path -Recurse -File
$Files = $Files | Where-Object { $_.Name -notlike "*_Hashes.txt" -and $_.Name -notlike "HashGroup.ps1" } # ignore hash output files and script if present
if ($Files.Count -eq 0) { return } # exit if no files found

foreach ($File in $Files) {
  switch ($Algorithm) {
    'MD5' { $HashMD5 = ((Get-FileHash $File -Algorithm MD5 | Select-Object Hash) -split " ").Trim("@{Hash=}") }
    'SHA1' { $HashSHA1 = ((Get-FileHash $File -Algorithm SHA1 | Select-Object Hash) -split " ").Trim("@{Hash=}") }
    'SHA256' { $HashSHA256 = ((Get-FileHash $File -Algorithm SHA256 | Select-Object Hash) -split " ").Trim("@{Hash=}") }
    'SHA512' { $HashSHA512 = ((Get-FileHash $File -Algorithm SHA512 | Select-Object Hash) -split " ").Trim("@{Hash=}") }
    default {
      $HashMD5 = ((Get-FileHash $File -Algorithm MD5 | Select-Object Hash) -split " ").Trim("@{Hash=}")
      $HashSHA1 = ((Get-FileHash $File -Algorithm SHA1 | Select-Object Hash) -split " ").Trim("@{Hash=}")
      $HashSHA256 = ((Get-FileHash $File -Algorithm SHA256 | Select-Object Hash) -split " ").Trim("@{Hash=}")
      $HashSHA512 = ((Get-FileHash $File -Algorithm SHA512 | Select-Object Hash) -split " ").Trim("@{Hash=}")
    }
  }

  # outout to text file
  $OutFile = "$Path\#HashGroup\$($File.Name)_Hashes.txt"
  if (Test-Path $OutFile) { continue } # skip if file already exists
  else {
    "MD5: $HashMD5" | Out-File -FilePath $OutFile -Append -Encoding utf8
    "SHA1: $HashSHA1" | Out-File -FilePath $OutFile -Append -Encoding utf8
    "SHA256: $HashSHA256" | Out-File -FilePath $OutFile -Append -Encoding utf8
    "SHA512: $HashSHA512" | Out-File -FilePath $OutFile -Append -Encoding utf8
  }
}