Functions/Get-FileEncoding.ps1

# source: https://gist.github.com/jpoehls/2406504
function Get-FileEncoding {
    <#
.SYNOPSIS
    To get the file encoding of a file
.DESCRIPTION
    To get the file encoding of a file
.PARAMETER Path
    The file that you want to check its encoding.
.EXAMPLE
    Get-FileEncoding -Path .\UTF16-BigEndian.txt
 
    Unicode UTF-16 Big-Endian
.EXAMPLE
    Get-FileEncoding -Path .\UTF16-LittleEndian.txt
 
    Unicode UTF-16 Little-Endian
#>


    [CmdletBinding()]
    Param (
        [Parameter(Mandatory, HelpMessage = 'Please enter the path to a file', ValueFromPipelineByPropertyName)]
        [string] $Path
    )

    if (Test-Path -Path $Path){
        [byte[]] $byte = Get-Content -Encoding byte -ReadCount 4 -TotalCount 4 -Path $Path
        #Write-Host Bytes: $byte[0] $byte[1] $byte[2] $byte[3]

        if ( $byte[0] -eq 0xef -and $byte[1] -eq 0xbb -and $byte[2] -eq 0xbf ) {
            # EF BB BF (UTF8)
            Write-Output -inputobject 'UTF8'
        } elseif ($byte[0] -eq 0xfe -and $byte[1] -eq 0xff) {
            # FE FF (UTF-16 Big-Endian)
            Write-Output -inputobject 'Unicode UTF-16 Big-Endian'
        } elseif ($byte[0] -eq 0xff -and $byte[1] -eq 0xfe) {
            # FF FE (UTF-16 Little-Endian)
            Write-Output -inputobject 'Unicode UTF-16 Little-Endian'
        } elseif ($byte[0] -eq 0 -and $byte[1] -eq 0 -and $byte[2] -eq 0xfe -and $byte[3] -eq 0xff) {
            # 00 00 FE FF (UTF32 Big-Endian)
            Write-Output -inputobject 'UTF32 Big-Endian'
        } elseif ($byte[0] -eq 0xfe -and $byte[1] -eq 0xff -and $byte[2] -eq 0 -and $byte[3] -eq 0) {
            # FE FF 00 00 (UTF32 Little-Endian)
            Write-Output -inputobject 'UTF32 Little-Endian'
        } elseif ($byte[0] -eq 0x2b -and $byte[1] -eq 0x2f -and $byte[2] -eq 0x76 -and ($byte[3] -eq 0x38 -or $byte[3] -eq 0x39 -or $byte[3] -eq 0x2b -or $byte[3] -eq 0x2f) ) {
            # 2B 2F 76 (38 | 38 | 2B | 2F)
            Write-Output -inputobject 'UTF7'
        } elseif ( $byte[0] -eq 0xf7 -and $byte[1] -eq 0x64 -and $byte[2] -eq 0x4c ) {
            # F7 64 4C (UTF-1)
            Write-Output -inputobject 'UTF-1'
        } elseif ($byte[0] -eq 0xdd -and $byte[1] -eq 0x73 -and $byte[2] -eq 0x66 -and $byte[3] -eq 0x73) {
            # DD 73 66 73 (UTF-EBCDIC)
            Write-Output -inputobject 'UTF-EBCDIC'
        } elseif ( $byte[0] -eq 0x0e -and $byte[1] -eq 0xfe -and $byte[2] -eq 0xff ) {
            # 0E FE FF (SCSU)
            Write-Output -inputobject 'SCSU'
        } elseif ( $byte[0] -eq 0x0e -and $byte[1] -eq 0xfe -and $byte[2] -eq 0xff ) {
            Write-Output -inputobject 'SCSU'
        } elseif ( $byte[0] -eq 0xfb -and $byte[1] -eq 0xee -and $byte[2] -eq 0x28 ) {
            # FB EE 28 (BOCU-1)
            Write-Output -inputobject 'BOCU-1'
        } elseif ($byte[0] -eq 0x84 -and $byte[1] -eq 0x31 -and $byte[2] -eq 0x95 -and $byte[3] -eq 0x33) {
            # 84 31 95 33 (GB-18030)
            Write-Output -inputobject 'GB-18030'
        } else {
            Write-Output -inputobject 'ASCII'
        }
    } else {
        Write-Error -Message "The file [$Path] does not exist."
    }

}