Extended Commands and Command Completion

Emacs has the concept of extended commands, which consist of M-x followed by the name of the command. As an example of a useful extended command, sometimes the backspace key gets mapped to C-h (I find this happens sometimes under remote screen sessions, you'll know this is the case if you hit the backspace key twice and the emacs help buffer pops up, just hit C-g to clear the help window). To get the backspace key to act as it should (i.e., it deletes the previous character), you enter M-x normal-erase-is-backspace-mode. That's a lot to type, so you can take advantage of Emacs' command-completion by typing a partial command and hitting the Tab key one or more times. In this case, you type M-x normal-e and hit Tab, and Emacs will complete the command for you. You can then just hit Enter to execute the command. If you don't type enough of the command to make it unique, Emacs will display a list of alternatives for you to choose from. For example, if you type M-x normal- and hit the Tab key, Emacs will pop up a buffer named *Completion* with with two alternatives for you to choose from: normal-mode and mormal-erase-is-backspace-mode. Just type a bit more of the command you want and hit tab again to narrow the completion list or to complete the command if it is the only one left.