How to WriteAllLines in C# without CRLF

Assuming you still actually want the linebreaks, you just want line feeds instead of carriage return / line feed, you could use:

File.WriteAllText(myOutputFile, string.Join("\n", lines));

or if you definitely want a line break after the last line too:

File.WriteAllText(myOutputFile, string.Join("\n", lines) + "\n");

(Alternatively, as you say, you could fix it on the Linux side, e.g. with dos2unix.)