PowerShell's pipe adds linefeed

Introduction

Here is my Invoke-RawPipeline function (get latest version from this Gist).

Use it to pipe binary data between processes' Standard Output and Standard Input streams. It can read input stream from file/pipeline and save resulting output stream to file.

It requires PsAsync module to be able to launch and pipe data in multiple processes.

In case of issues use -Verbose switch to see debug output.

Examples

Redirecting to file

• Batch:
  findstr.exe /C:"Warning" /I C:\Windows\WindowsUpdate.log > C:\WU_Warnings.txt
• PowerShell:
  Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; Arguments = '/C:"Warning" /I C:\Windows\WindowsUpdate.log'} -OutFile 'C:\WU_Warnings.txt'

Redirecting from file

• Batch:
  svnadmin load < C:\RepoDumps\MyRepo.dump
• PowerShell:
  Invoke-RawPipeline -InFile 'C:\RepoDumps\MyRepo.dump' -Command @{Path = 'svnadmin.exe' ; Arguments = 'load'}

Piping strings

• Batch:
  echo TestString | find /I "test" > C:\SearchResult.log
• PowerShell:
  'TestString' | Invoke-RawPipeline -Command @{Path = 'find.exe' ; Arguments = '/I "test"'} -OutFile 'C:\SearchResult.log'

Piping between multiple processes

• Batch:
  ipconfig | findstr /C:"IPv4 Address" /I
• PowerShell:
  Invoke-RawPipeline -Command @{Path = 'ipconfig'}, @{Path = 'findstr' ; Arguments = '/C:"IPv4 Address" /I'} -RawData

Code:

<#
.Synopsis
    Pipe binary data between processes' Standard Output and Standard Input streams.
    Can read input stream from file and save resulting output stream to file.

.Description
    Pipe binary data between processes' Standard Output and Standard Input streams.
    Can read input stream from file/pipeline and save resulting output stream to file.
    Requires PsAsync module: http://psasync.codeplex.com

.Notes
    Author: beatcracker (https://beatcracker.wordpress.com, https://github.com/beatcracker)
    License: Microsoft Public License (http://opensource.org/licenses/MS-PL)

.Component
    Requires PsAsync module: http://psasync.codeplex.com

.Parameter Command
    An array of hashtables, each containing Command Name, Working Directory and Arguments

.Parameter InFile
    This parameter is optional.

    A string representing path to file, to read input stream from.

.Parameter OutFile
    This parameter is optional.

    A string representing path to file, to save resulting output stream to.

.Parameter Append
    This parameter is optional. Default is false.

    A switch controlling wheither ovewrite or append output file if it already exists. Default is to overwrite.

.Parameter IoTimeout
    This parameter is optional. Default is 0.

    A number of seconds to wait if Input/Output streams are blocked. Default is to wait indefinetely.

.Parameter ProcessTimeout
    This parameter is optional. Default is 0.

    A number of seconds to wait for process to exit after finishing all pipeline operations. Default is to wait indefinetely.
    Details: https://msdn.microsoft.com/en-us/library/ty0d8k56.aspx

.Parameter BufferSize
    This parameter is optional. Default is 4096.

    Size of buffer in bytes for read\write operations. Supports standard Powershell multipliers: KB, MB, GB, TB, and PB.
    Total number of buffers is: Command.Count * 2 + InFile + OutFile.

.Parameter ForceGC
    This parameter is optional.

    A switch, that if specified will force .Net garbage collection.
    Use to immediately release memory on function exit, if large buffer size was used.

.Parameter RawData
    This parameter is optional.

    By default function returns object with StdOut/StdErr streams and process' exit codes.
    If this switch is specified, function will return raw Standard Output stream.

.Example
    Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; Arguments = '/C:"Warning" /I C:\Windows\WindowsUpdate.log'} -OutFile 'C:\WU_Warnings.txt'

    Batch analog: findstr.exe /C:"Warning" /I C:\Windows\WindowsUpdate.log' > C:\WU_Warnings.txt

.Example
    Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; WorkingDirectory = 'C:\Windows' ; Arguments = '/C:"Warning" /I .\WindowsUpdate.log'} -RawData

    Batch analog: cd /D C:\Windows && findstr.exe /C:"Warning" /I .\WindowsUpdate.log

.Example
    'TestString' | Invoke-RawPipeline -Command @{Path = 'find.exe' ; Arguments = '/I "test"'} -OutFile 'C:\SearchResult.log'

    Batch analog: echo TestString | find /I "test" > C:\SearchResult.log

.Example
    Invoke-RawPipeline -Command @{Path = 'ipconfig'}, @{Path = 'findstr' ; Arguments = '/C:"IPv4 Address" /I'} -RawData

    Batch analog: ipconfig | findstr /C:"IPv4 Address" /I

.Example
    Invoke-RawPipeline -InFile 'C:\RepoDumps\Repo.svn' -Command @{Path = 'svnadmin.exe' ; Arguments = 'load'}

    Batch analog: svnadmin load < C:\RepoDumps\MyRepo.dump
#>

function Invoke-RawPipeline
{
    [CmdletBinding()]
    Param
    (
        [Parameter(ValueFromPipeline = $true)]
        [ValidateNotNullOrEmpty()]
        [ValidateScript({
            if($_.psobject.Methods.Match.('ToString'))
            {
                $true
            }
            else
            {
                throw 'Can''t convert pipeline object to string!'
            }
        })]
        $InVariable,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [ValidateScript({
            $_ | ForEach-Object {
                $Path = $_.Path
                $WorkingDirectory = $_.WorkingDirectory

                if(!(Get-Command -Name $Path -CommandType Application -ErrorAction SilentlyContinue))
                {
                    throw "Command not found: $Path"
                }

                if($WorkingDirectory)
                {
                    if(!(Test-Path -LiteralPath $WorkingDirectory -PathType Container -ErrorAction SilentlyContinue))
                    {
                        throw "Working directory not found: $WorkingDirectory"
                    }
                }
            }
            $true
        })]
        [ValidateNotNullOrEmpty()]
        [array]$Command,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [ValidateScript({
            if(!(Test-Path -LiteralPath $_))
            {
                throw "File not found: $_"
            }
            $true
        })]
        [ValidateNotNullOrEmpty()]
        [string]$InFile,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [ValidateScript({
            if(!(Test-Path -LiteralPath (Split-Path $_)))
            {
                throw "Folder not found: $_"
            }
            $true
        })]
        [ValidateNotNullOrEmpty()]
        [string]$OutFile,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [switch]$Append,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [ValidateRange(0, 2147483)]
        [int]$IoTimeout = 0,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [ValidateRange(0, 2147483)]
        [int]$ProcessTimeout = 0,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [long]$BufferSize = 4096,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [switch]$RawData,

        [Parameter(ValueFromPipelineByPropertyName = $true)]
        [switch]$ForceGC
    )

    Begin
    {

        $Modules = @{PsAsync = 'http://psasync.codeplex.com'}

        'Loading modules:', ($Modules | Format-Table -HideTableHeaders -AutoSize | Out-String) | Write-Verbose

        foreach($module in $Modules.GetEnumerator())
        {
            if(!(Get-Module -Name $module.Key))
            {
                Try
                { 
                    Import-Module -Name $module.Key -ErrorAction Stop
                }
                Catch
                {
                    throw "$($module.Key) module not available. Get it here: $($module.Value)"
                }
            }
        }

        function New-ConsoleProcess
        {
            Param
            (
                [string]$Path,
                [string]$Arguments,
                [string]$WorkingDirectory,
                [switch]$CreateNoWindow = $true,
                [switch]$RedirectStdIn = $true,
                [switch]$RedirectStdOut = $true,
                [switch]$RedirectStdErr = $true
            )

            if(!$WorkingDirectory)
            {
                if(!$script:MyInvocation.MyCommand.Path)
                {
                    $WorkingDirectory = [System.AppDomain]::CurrentDomain.BaseDirectory
                }
                else
                {
                    $WorkingDirectory = Split-Path $script:MyInvocation.MyCommand.Path
                }
            }

            Try
            {
                $ps = New-Object -TypeName System.Diagnostics.Process -ErrorAction Stop
                $ps.StartInfo.Filename = $Path
                $ps.StartInfo.Arguments = $Arguments
                $ps.StartInfo.UseShellExecute = $false
                $ps.StartInfo.RedirectStandardInput = $RedirectStdIn
                $ps.StartInfo.RedirectStandardOutput = $RedirectStdOut
                $ps.StartInfo.RedirectStandardError = $RedirectStdErr
                $ps.StartInfo.CreateNoWindow = $CreateNoWindow
                $ps.StartInfo.WorkingDirectory = $WorkingDirectory
            }
            Catch
            {
                throw $_
            }

            return $ps
        }

        function Invoke-GarbageCollection
        {
            [gc]::Collect()
            [gc]::WaitForPendingFinalizers()
        }

        $CleanUp = {
            $IoWorkers + $StdErrWorkers |
            ForEach-Object {
                $_.Src, $_.Dst |
                ForEach-Object {
                    if(!($_ -is [System.Diagnostics.Process]))
                    {
                        Try
                        {
                            $_.Close()
                        }
                        Catch
                        {
                            Write-Error "Failed to close $_"
                        }
                        $_.Dispose()
                    }

                }
            }
        }

        $PumpData = {
            Param
            (
                [hashtable]$Cfg
            )
            # Fail hard, we don't want stuck threads
            $Private:ErrorActionPreference = 'Stop'

            $Src = $Cfg.Src
            $SrcEndpoint = $Cfg.SrcEndpoint
            $Dst = $Cfg.Dst
            $DstEndpoint = $Cfg.DstEndpoint
            $BufferSize = $Cfg.BufferSize
            $SyncHash = $Cfg.SyncHash
            $RunspaceId = $Cfg.Id
        
            # Setup Input and Output streams
            if($Src -is [System.Diagnostics.Process])
            {
                switch ($SrcEndpoint)
                {
                    'StdOut' {$InStream = $Src.StandardOutput.BaseStream}
                    'StdIn' {$InStream = $Src.StandardInput.BaseStream}
                    'StdErr' {$InStream = $Src.StandardError.BaseStream}
                    default {throw "Not valid source endpoint: $_"}
                }
            }
            else
            {
                $InStream = $Src
            }

            if($Dst -is [System.Diagnostics.Process])
            {
                switch ($DstEndpoint)
                {
                    'StdOut' {$OutStream = $Dst.StandardOutput.BaseStream}
                    'StdIn' {$OutStream = $Dst.StandardInput.BaseStream}
                    'StdErr' {$OutStream = $Dst.StandardError.BaseStream}
                    default {throw "Not valid destination endpoint: $_"}
                }
            }            
            else
            {
                $OutStream = $Dst
            }

            $InStream | Out-String | ForEach-Object {$SyncHash.$RunspaceId.Status += "InStream: $_"}
            $OutStream | Out-String | ForEach-Object {$SyncHash.$RunspaceId.Status += "OutStream: $_"}

            # Main data copy loop
            $Buffer = New-Object -TypeName byte[] $BufferSize
            $BytesThru = 0

            Try
            {
                Do
                {
                    $SyncHash.$RunspaceId.IoStartTime = [DateTime]::UtcNow.Ticks
                    $ReadCount = $InStream.Read($Buffer, 0, $Buffer.Length)
                    $OutStream.Write($Buffer, 0, $ReadCount)
                    $OutStream.Flush()
                    $BytesThru += $ReadCount
                }
                While($readCount -gt 0)
            }
            Catch
            {
                $SyncHash.$RunspaceId.Status += $_
        
            }
            Finally
            {
                $OutStream.Close()
                $InStream.Close()
            }
        }
    }

    Process
    {
        $PsCommand = @()
        if($Command.Length)
        {
            Write-Verbose 'Creating new process objects'
            $i = 0
            foreach($cmd in $Command.GetEnumerator())
            {
                $PsCommand += New-ConsoleProcess @cmd
                $i++
            }
        }

        Write-Verbose 'Building I\O pipeline'
        $PipeLine = @()
        if($InVariable)
        {
                [Byte[]]$InVarBytes = [Text.Encoding]::UTF8.GetBytes($InVariable.ToString())
                $PipeLine += New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
                $PipeLine[-1].Write($InVarBytes, 0, $InVarBytes.Length)
                [Void]$PipeLine[-1].Seek(0, 'Begin')
        }
        elseif($InFile)
        {
            $PipeLine += New-Object -TypeName System.IO.FileStream -ArgumentList ($InFile, [IO.FileMode]::Open) -ErrorAction Stop
            if($PsCommand.Length)
            {
                $PsCommand[0].StartInfo.RedirectStandardInput = $true
            }
        }
        else
        {
            if($PsCommand.Length)
            {
                $PsCommand[0].StartInfo.RedirectStandardInput = $false
            }
        }

        $PipeLine += $PsCommand

        if($OutFile)
        {
            if($PsCommand.Length)
            {
                $PsCommand[-1].StartInfo.RedirectStandardOutput = $true
            }

            if($Append)
            {
                $FileMode = [System.IO.FileMode]::Append
            }
            else
            {
                $FileMode = [System.IO.FileMode]::Create
            }

            $PipeLine += New-Object -TypeName System.IO.FileStream -ArgumentList ($OutFile, $FileMode, [System.IO.FileAccess]::Write) -ErrorAction Stop
        }
        else
        {
            if($PsCommand.Length)
            {
                $PipeLine += New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
            }
        }
    
        Write-Verbose 'Creating I\O threads'
        $IoWorkers = @()
        for($i=0 ; $i -lt ($PipeLine.Length-1) ; $i++)
        {
            $SrcEndpoint = $DstEndpoint = $null
            if($PipeLine[$i] -is [System.Diagnostics.Process])
            {
                $SrcEndpoint = 'StdOut'
            }
            if($PipeLine[$i+1] -is [System.Diagnostics.Process])
            {
                $DstEndpoint = 'StdIn'
            }

            $IoWorkers += @{
                Src = $PipeLine[$i]
                SrcEndpoint = $SrcEndpoint
                Dst = $PipeLine[$i+1]
                DstEndpoint = $DstEndpoint
            }
        }
        Write-Verbose "Created $($IoWorkers.Length) I\O worker objects"

        Write-Verbose 'Creating StdErr readers'
        $StdErrWorkers = @()
        for($i=0 ; $i -lt $PsCommand.Length ; $i++)
        {
            $StdErrWorkers += @{
                Src = $PsCommand[$i]
                SrcEndpoint = 'StdErr'
                Dst = New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
            }
        }
        Write-Verbose "Created $($StdErrWorkers.Length) StdErr reader objects"

        Write-Verbose 'Starting processes'
        $PsCommand |
            ForEach-Object {
                $ps = $_
                Try
                {
                    [void]$ps.Start()
                }
                Catch
                {
                    Write-Error "Failed to start process: $($ps.StartInfo.FileName)"
                    Write-Verbose "Can't launch process, killing and disposing all"

                    if($PsCommand)
                    {
                        $PsCommand |
                            ForEach-Object {
                                Try{$_.Kill()}Catch{} # Can't do much if kill fails...
                                $_.Dispose()
                            }
                    }

                        Write-Verbose 'Closing and disposing I\O streams'
                    . $CleanUp
                }
                Write-Verbose "Started new process: Name=$($ps.Name), Id=$($ps.Id)"
            }

        $WorkersCount = $IoWorkers.Length + $StdErrWorkers.Length
        Write-Verbose 'Creating sync hashtable'
        $sync = @{}
        for($i=0 ; $i -lt $WorkersCount ; $i++)
        {
            $sync += @{$i = @{IoStartTime = $nul ; Status = $null}}
        }
        $SyncHash = [hashtable]::Synchronized($sync)

        Write-Verbose 'Creating runspace pool'
        $RunspacePool = Get-RunspacePool $WorkersCount

        Write-Verbose 'Loading workers on the runspace pool'
        $AsyncPipelines = @()
        $i = 0
        $IoWorkers + $StdErrWorkers |
        ForEach-Object {
            $Param = @{
                BufferSize = $BufferSize
                Id = $i
                SyncHash = $SyncHash
            } + $_

            $AsyncPipelines += Invoke-Async -RunspacePool $RunspacePool -ScriptBlock $PumpData -Parameters $Param
            $i++

            Write-Verbose 'Started working thread'
            $Param | Format-Table -HideTableHeaders -AutoSize | Out-String | Write-Debug
        }

        Write-Verbose 'Waiting for I\O to complete...'
        if($IoTimeout){Write-Verbose "Timeout is $IoTimeout seconds"}

        Do
        {
            # Check for pipelines with errors
            [array]$FailedPipelines = Receive-AsyncStatus -Pipelines $AsyncPipelines | Where-Object {$_.Completed -and $_.Error}
            if($FailedPipelines)
            {
                "$($FailedPipelines.Length) pipeline(s) failed!",
                ($FailedPipelines | Select-Object -ExpandProperty Error | Format-Table -AutoSize | Out-String) | Write-Debug
            }

            if($IoTimeout)
            {
                # Compare I\O start time of thread with current time
                [array]$LockedReaders = $SyncHash.Keys | Where-Object {[TimeSpan]::FromTicks([DateTime]::UtcNow.Ticks - $SyncHash.$_.IoStartTime).TotalSeconds -gt $IoTimeout}
                if($LockedReaders)
                {
                    # Yikes, someone is stuck
                    "$($LockedReaders.Length) I\O operations reached timeout!" | Write-Verbose
                    $SyncHash.GetEnumerator() | ForEach-Object {"$($_.Key) = $($_.Value.Status)"} | Sort-Object | Out-String | Write-Debug
                    $PsCommand | ForEach-Object {
                        Write-Verbose "Killing process: Name=$($_.Name), Id=$($_.Id)"
                        Try
                        {
                            $_.Kill()
                        }
                        Catch
                        {
                            Write-Error 'Failed to kill process!'
                        }
                    }
                    break
                }
            }
            Start-Sleep 1
        }
        While(Receive-AsyncStatus -Pipelines $AsyncPipelines | Where-Object {!$_.Completed}) # Loop until all pipelines are finished

        Write-Verbose 'Waiting for all pipelines to finish...'
        $IoStats = Receive-AsyncResults -Pipelines $AsyncPipelines
        Write-Verbose 'All pipelines are finished'

        Write-Verbose 'Collecting StdErr for all processes'
        $PipeStdErr = $StdErrWorkers |
            ForEach-Object {
                $Encoding = $_.Src.StartInfo.StandardOutputEncoding
                if(!$Encoding)
                {
                    $Encoding = [System.Text.Encoding]::Default
                }
                @{
                    FileName = $_.Src.StartInfo.FileName
                    StdErr = $Encoding.GetString($_.Dst.ToArray())
                    ExitCode = $_.Src.ExitCode
                }
            } | 
                Select-Object   @{Name = 'FileName' ; Expression = {$_.FileName}},
                                @{Name = 'StdErr' ; Expression = {$_.StdErr}},
                                @{Name = 'ExitCode' ; Expression = {$_.ExitCode}}

        if($IoWorkers[-1].Dst -is [System.IO.MemoryStream])
        {
            Write-Verbose 'Collecting final pipeline output'
                if($IoWorkers[-1].Src -is [System.Diagnostics.Process])
                {
                    $Encoding = $IoWorkers[-1].Src.StartInfo.StandardOutputEncoding
                }
                if(!$Encoding)
                {
                    $Encoding = [System.Text.Encoding]::Default
                }
                $PipeResult = $Encoding.GetString($IoWorkers[-1].Dst.ToArray())
        }


        Write-Verbose 'Closing and disposing I\O streams'
        . $CleanUp

        $PsCommand |
            ForEach-Object {
                $_.Refresh()
                if(!$_.HasExited)
                {
                    Write-Verbose "Process is still active: Name=$($_.Name), Id=$($_.Id)"
                    if(!$ProcessTimeout)
                    {
                        $ProcessTimeout = -1
                    }
                    else
                    {
                        $WaitForExitProcessTimeout = $ProcessTimeout * 1000
                    }
                    Write-Verbose "Waiting for process to exit (Process Timeout = $ProcessTimeout)"
                    if(!$_.WaitForExit($WaitForExitProcessTimeout))
                    {
                        Try
                        {
                            Write-Verbose 'Trying to kill it'
                            $_.Kill()
                        }
                        Catch
                        {
                            Write-Error "Failed to kill process $_"
                        }
                    }
                }
                Write-Verbose "Disposing process object: Name=$($_.StartInfo.FileName)"
                $_.Dispose()
            }

        Write-Verbose 'Disposing runspace pool'
        # http://stackoverflow.com/questions/21454252/how-to-cleanup-resources-in-a-dll-when-powershell-ise-exits-like-new-pssession
        $RunspacePool.Dispose()

        if($ForceGC)
        {
            Write-Verbose 'Forcing garbage collection'
            Invoke-GarbageCollection
        }
    
        if(!$RawData)
        {
            New-Object -TypeName psobject -Property @{Result = $PipeResult ; Status = $PipeStdErr}
        }
        else
        {
            $PipeResult
        }
    }
}

Bruteforce approach: feed binary data to process' stdin. I've tested this code on the cat.exe from UnixUtils and it seems to do what you want:

# Text to send
$InputVar = "No Newline, No NewLine,`nNewLine, No NewLine,`nNewLine, No NewLine"

# Buffer & initial size of MemoryStream
$BufferSize = 4096

# Convert text to bytes and write to MemoryStream
[byte[]]$InputBytes = [Text.Encoding]::UTF8.GetBytes($InputVar)
$MemStream = New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize
$MemStream.Write($InputBytes, 0, $InputBytes.Length)
[Void]$MemStream.Seek(0, 'Begin')

# Setup stdin\stdout redirection for our process
$StartInfo = New-Object -TypeName System.Diagnostics.ProcessStartInfo -Property @{
                FileName = 'MyLittle.exe'
                UseShellExecute = $false
                RedirectStandardInput = $true
            }

# Create new process
$Process = New-Object -TypeName System.Diagnostics.Process

# Assign previously created StartInfo properties
$Process.StartInfo = $StartInfo
# Start process
[void]$Process.Start()

# Pipe data
$Buffer = New-Object -TypeName byte[] -ArgumentList $BufferSize
$StdinStream = $Process.StandardInput.BaseStream

try
{
    do
    {
        $ReadCount = $MemStream.Read($Buffer, 0, $Buffer.Length)
        $StdinStream.Write($Buffer, 0, $ReadCount)
        $StdinStream.Flush()
    }
    while($ReadCount -gt 0)
}
catch
{
    throw 'Houston, we have a problem!'           
}
finally
{
    # Close streams
    $StdinStream.Close()
    $MemStream.Close()
}

# Cleanup
'Process', 'StdinStream', 'MemStream' |
    ForEach-Object {
        (Get-Variable $_ -ValueOnly).Dispose()
        Remove-Variable $_ -Force
    }