var MyFileObj = new File("My_Output.txt");

function ReportInitialization() {
    MyFileObj.writeln("Now initializing...");
}

function ReportNewBarData() {
    MyFileObj.writeln("Here is new bar data...");
}

function ReportEODSummary() {
    MyFileObj.writeln("Here is EOD summary...");
}

function preMain() {
    MyFileObj.open("wt");   // One time only: if file exists, overwrite it
    ReportInitialization();
    MyFileObj.flush();
    MyFileObj.close();
}

function main() {
    MyFileObj.open("at");   // Open existing file for writing = appending
         // ...other code...
    if (getBarState() == BARSTATE_NEWBAR) {ReportNewBarData()}
    if (MyTime = LastBarOfDay) {ReportEODSummary()}
    MyFileObj.flush();
    MyFileObj.close();
}