I have come up to another very informative document about the transaction codes that SAP Beginners will find interesting notes. Actually my curiosity increases about the author of this document, M Rajagopalan, coz I ve seen his name on many useful SAP related documents but no chance to meet any of his profile on web. I would rather want to know more about him. Anyway, regarding the document you will find following notes;
How to display all transaction code in SAP
Use of Command Line
Determining transaction code
and the most useful part that you will understand the structure of t.codes: What is Naming Standarts of Transaction Codes ?