Find files with specific line endings or mixed line endings

Get-LineEnding.ps1

function Get-LineEnding {
    <#
    .SYNOPSIS
    Returns the line ending found in a given file.
    
    .DESCRIPTION
    Returns a [PSCustomObject] with a `LineEnding` property with the value
    'CRLF', 'LF', or 'MIXED' depending on the line endings found in the file.
    
    .EXAMPLE
    Get-ChildItem *.ps1 -Recurse | Get-LineEnding | Where-Object LineEnding -eq 'MIXED'
    
    Returns any .PS1 file in the current directory or any subdirectory where
    there are a mix of CRLF and LF line endings.

    .NOTES
    This function does not distinguish between text and binary files, and it
    reads files byte by byte, so you should take care not to pass in paths of
    large binary files.
    #>
    [CmdletBinding()]
    param(
        [Parameter(Mandatory, Position = 0, ValueFromPipeline, ValueFromPipelineByPropertyName)]
        [Alias('FullName')]
        [string]
        $Path,

        [Parameter()]
        [Switch]
        $ResolveRelativePath
    )

    begin {
        $CR, $LF = [byte[]](13, 10)
    }

    process {
        $pathParams = @{
            Path        = $Path
            ErrorAction = 'Stop'
        }
        if ($ResolveRelativePath) {
            $pathParams.Relative = $true
        }
        $Path = [string](Resolve-Path @pathParams)
        if (-not (Test-Path -Path $Path -PathType Leaf)) {
            Write-Error "The path '$Path' does not exist or is not a file."
            return
        }

        $lineEnding = $null
        try {
            $lastByte = [byte]0
            $fs = [io.file]::OpenRead($Path)
            while ($fs.Position -lt $fs.Length) {
                $byte = $fs.ReadByte()
                if ($byte -eq $LF) {
                    if ($lastByte -eq $CR) {
                        if ($lineEnding -eq 'LF') {
                            $lineEnding = 'MIXED'
                            break
                        }
                        $lineEnding = 'CRLF'
                    } else {
                        if ($lineEnding -eq 'CRLF') {
                            $lineEnding = 'MIXED'
                            break
                        }
                        $lineEnding = 'LF'
                    }
                }
                $lastByte = $byte
            }
            [pscustomobject]@{
                Path       = $Path
                LineEnding = $lineEnding
            }
        } finally {
            $fs.Dispose()
        }
    }
}