Merge files in a directory using Linq to Objects

I have a set of txt files in a directory. I want to merge them all in to one with contects appended. How can this be ac开发者_Python百科hieved using Linq?

You can do this in .Net 4 relatively easily:

File.WriteAllLines(
    outputFileName,
    Directory.EnumerateFiles(inputDirectory, @"*.txt")
             .SelectMany(file => File.ReadLines(file)));

You could extract this into a method:

public static void ConcatenateFiles(
    string outputFileName, IEnumerable<string> inputFiles)
{
    File.WriteAllLines(outputFileName, inputFiles.SelectMany(File.ReadLines));
}

Called like so:

ConcatenateFiles("test.out", Directory.EnumerateFiles(inputDirectory, @"*.txt"));