You can keep a log by using the same method as Notepad. Just add ".LOG" on the first line (without the quotation marks) and every time you open such a document, the editor will append the current date and time (as specified by your computer's clock).There is an option that lets you configure the format for the date and time text that is pasted with the corresponding command. The Date and Time filters topic gives you all the codes you can use to build a filter.