>perldoc perlopentut | grep -in append
366:        O_APPEND            Append to the file
395:    To open a file for appending, creating one if necessary:
398:        sysopen(FH, $path, O_WRONLY | O_APPEND | O_CREAT);
414:    To open a file for appending, where that file must already exist:
416:        sysopen(FH, $path, O_WRONLY | O_APPEND);
523:    starts with whitespace. Trailing whitespace is protected by appending an