# 下载 Calibre ， 找到 ebook-convert.exe

$app = ".\ebook-convert.exe" #  ebook-convert.exe 路径 
$root = ".\epub\" # 电子书路径 

Get-ChildItem "$root\*.epub" | %  FullName | % {

    $newPath = [System.IO.Path]::ChangeExtension($_, ".mobi")

    if (-not [System.IO.File]::Exists($newPath))
    {
        & $app $_ $newPath
        if (-not $?)
        {
            throw [System.ApplicationException]::new("文件 $_ 转换失败")
        }
    }
}