Part 2: Extract the old data file
Click to go back input data panel. This time you want information only in the second file. So scroll down to the top of File2. Right click and drag over the second file name “old_data.txt”. The file name will be highlighted green. Everything in the first file is highlighted pink.
Push the shift button on your keyboard, and right click and drag over as many area as you can on a line in the file. That will select all the data in the old data file.
It looks like following:
Click button to move the selected data to panel, and name the new rule “old_data”.
Now we are ready to update the old data.