Speeding Up Entering Commands
Now you’ve learned a few basic commands, we can teach you a few tricks to speed up your use of the shell.
First of all, the shell keeps a record of the commands you enter called your history, so you can save retyping if you want to reuse a command. If you want to reuse the last command, just type in two exclamation marks and press Enter. If you want to use an earlier command, tapping the up arrow brings back your previous commands in order (most recent first) and puts them after your prompt. The down arrow moves through your history in the other direction if you overshoot the command you want. You can edit the command before pressing Enter to issue it.
The shell also tries to guess what you want to type and automatically completes it for you if you tap the Tab key. You can use it for commands and files. For example, type
and then press the Tab key, and the path is completed as /boot/.
This technique is particularly helpful if you’re dealing with long and complicated filenames. If it doesn’t work, you haven’t given the shell enough of a hint, so you need to give it some more letters to be sure what you mean.