UNIX format files with Powershell

How do you create a unix file format in Powershell? I am using the following to create a file, but it always creates it in the windows format.

"hello world" | out-file -filepath test.txt -append

As I understand, the new line characters CRLF make it to be a Windows format file whereas the unix format needs only a LF at the end of the line. I tried 开发者_Python百科replacing the CRLF with the following, but it didn't work

"hello world" | %{ $_.Replace("`r`n","`n") } | out-file -filepath test.txt -append

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There is a Cmdlet in the PowerShell Community Extensions called ConvertTo-UnixLineEnding

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One ugly-looking answer is (taking input from dos.txt outputting to unix.txt):

[string]::Join( "`n", (gc dos.txt)) | sc unix.txt

but I would really like to be able to make Set-Content do this by itself and this solution does not stream and therefore does not work well on large files...

And this solution will end the file with a DOS line ending as well... so it is not 100%

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I've found that solution:

sc unix.txt ([byte[]][char[]] "$contenttext") -Encoding Byte

posted above, fails on encoding convertions in some cases.

So, here is yet another solution (a bit more verbose, but it works directly with bytes):

function ConvertTo-LinuxLineEndings($path) {
    $oldBytes = [io.file]::ReadAllBytes($path)
    if (!$oldBytes.Length) {
        return;
    }
    [byte[]]$newBytes = @()
    [byte[]]::Resize([ref]$newBytes, $oldBytes.Length)
    $newLength = 0
    for ($i = 0; $i -lt $oldBytes.Length - 1; $i++) {
        if (($oldBytes[$i] -eq [byte][char]"`r") -and ($oldBytes[$i + 1] -eq [byte][char]"`n")) {
            continue;
        }
        $newBytes[$newLength++] = $oldBytes[$i]
    }
    $newBytes[$newLength++] = $oldBytes[$oldBytes.Length - 1]
    [byte[]]::Resize([ref]$newBytes, $newLength)
    [io.file]::WriteAllBytes($path, $newBytes)
}

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make your file in the Windows CRLF format. then convert all lines to Unix format in new file:

$streamWriter = New-Object System.IO.StreamWriter("\\wsl.localhost\Ubuntu\home\user1\.bashrc2")
$streamWriter.NewLine = "`n"
gc "\\wsl.localhost\Ubuntu\home\user1\.bashrc" | % {$streamWriter.WriteLine($_)}
$streamWriter.Flush()
$streamWriter.Close()

not a one-liner, but works for all lines, including EOF. new file now shows as Unix format in Notepad on Win11.

delete original file & rename new file to original, if you like:

ri "\\wsl.localhost\Ubuntu\home\user1\.bashrc" -Force
rni "\\wsl.localhost\Ubuntu\home\user1\.bashrc2" "\\wsl.localhost\Ubuntu\home\user1\.bashrc"

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Two more examples on how you can replace CRLF by LF:

1. Example:

   (Get-Content -Raw test.txt) -replace "`r`n","`n" | Set-Content test.txt -NoNewline
   

2. Example:

   [IO.File]::WriteAllText('C:\test.txt', ([IO.File]::ReadAllText('C:\test.txt') -replace "`r`n","`n"))
   

Be aware, this does really just replace CRLF by LF. You might need to add a trailing LF if your Windows file does not contain a trailing CRLF.