#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(['"`])(?:(?<!\\)\\(?:\\\\)*\1|(?!\1).)*\1(*SKIP)(*F)|\\n"
Local $sString = "\nnew"test\naaaa"\nta\n`this is a \nnewline that should be kept`\ntest\n'this \n should also be kept'\n" & @CRLF & _
"" & @CRLF & _
"\n`escaped quote:\` this should be kept: \n `\n" & @CRLF & _
"\n`not a escaped quote:\\` this should not be kept: \n `\n" & @CRLF & _
"\n`escaped quote:\\\` this should be kept: \n `\n"
Local $sSubst = ""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm