If we need to survive in IT industry then we need to keep our knowledge updated and for this purpose we need to read thick technical books or need to follow some tech forums. Once we read some technical stuff or some syntax it’s hard to recall that even after 15 days. To avoid this problem we usually read our notes, or revisit the original piece of info.
Here comes cheat sheets handy, Some of the websites provides cheat sheets or RefCards, Those are usually less than 5-6 page and you can carry them in your pockets.
Visit this website for more than 290 technical cheat sheets. http://www.cheat-sheets.org/