There are two basic levels of login:
Standard Read Mode (prompt looks like router-name>)
Enable Mode (prompt looks like router-name#)
You only ever need to type enough of the command to distinguish it from other commands.
You can always press the Tab key to finish the command you start typing.
If you are locked up by router output, press Ctrl+Shift+6+X.
? is the universal help command.
To see what commands are available beyond an initial command, enter Initial command ? (for example, show ?).
To save configuration changes, enter copy running-config startup-config.
To save a configuration to a Trivial File Transfer Protocol (TFTP) server, enter copy running-config tftp, and then follow the prompts.
Some good ...