[Wlug] Old man and LINUX

Folks, I have always wondered at my ability to keep the myriad of LINUX instructions in my head. What would I do if I were to start losing them? Is there a tool to search for recall? Is there any way to go backwards in LINUX command land? If I were to remember that there is a command that will print on standard output the contents of a file in txt characters, but could not for the life of me remember 'more'. Where would I go for help (other than sending a email to this list serve)? All the command dictionaries I have are alphabetic. Ken Jones (the elder)