更改多个文件扩展到UTF-8没有BOM:

$Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding($False)
foreach($i in ls -recurse -filter "*.java") {
    $MyFile = Get-Content $i.fullname 
    [System.IO.File]::WriteAllLines($i.fullname, $MyFile, $Utf8NoBomEncoding)
}

这是为我工作(使用“默认”而不是“UTF8”):

$MyFile = Get-Content $MyPath
$MyFile | Out-File -Encoding "Default" $MyPath

结果是没有BOM的ASCII。

老问题，新答案:

虽然“旧的”powershell写一个BOM，但新的平台不可知的变体确实表现不同:默认是“无BOM”，它可以通过switch配置:

-Encoding Specifies the type of encoding for the target file. The default value is utf8NoBOM. The acceptable values for this parameter are as follows: ascii: Uses the encoding for the ASCII (7-bit) character set. bigendianunicode: Encodes in UTF-16 format using the big-endian byte order. oem: Uses the default encoding for MS-DOS and console programs. unicode: Encodes in UTF-16 format using the little-endian byte order. utf7: Encodes in UTF-7 format. utf8: Encodes in UTF-8 format. utf8BOM: Encodes in UTF-8 format with Byte Order Mark (BOM) utf8NoBOM: Encodes in UTF-8 format without Byte Order Mark (BOM) utf32: Encodes in UTF-32 format.

来源:https://learn.microsoft.com/de-de/powershell/module/Microsoft.PowerShell.Utility/Out-File?view=powershell-7 我特别强调

更改多个文件扩展到UTF-8没有BOM:

$Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding($False)
foreach($i in ls -recurse -filter "*.java") {
    $MyFile = Get-Content $i.fullname 
    [System.IO.File]::WriteAllLines($i.fullname, $MyFile, $Utf8NoBomEncoding)
}

我认为这不会是UTF，但我只是发现了一个相当简单的解决方案，似乎工作…

Get-Content path/to/file.ext | out-file -encoding ASCII targetFile.ext

对我来说，这导致了一个没有bom文件的utf-8，不管源格式如何。

使用.NET的UTF8Encoding类并将$False传递给构造函数似乎是可行的:

$MyRawString = Get-Content -Raw $MyPath
$Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding $False
[System.IO.File]::WriteAllLines($MyPath, $MyRawString, $Utf8NoBomEncoding)