| Move one word to the right. |
| Esc, DAlt-D | Delete to the end of the current word. |
| Esc, BackspaceAlt-Backspace | Delete to the start of the current word. |
| HomeCtrl-A | Go to the start of the line. |
| EndCtrl-E | Go to the end of the line. |
4.1.1.3. Accessing previous commands
You can scroll through the history of previously entered commands using the up and down arrow keys. This enables you to easily re-enter a command, either exactly as you previously entered it or after editing.
You can also search for a previous command by pressing Ctrl-R (for reverse search ) and then typing a few characters that appear in the command. For example, if you had at some previous point typed cat /etc/hosts and you pressed Ctrl-R and typed hos , the cat /etc/hosts command would appear (providing that no intervening commands contained the letter sequence hos ).
4.1.1.4. Obtaining a root prompt to enter commands as the superuser
The superuser account, root , is also called the privileged account, because it is not subject to the security restrictions that are applied to regular user accounts. root access is required for many system administration commands. Although it's tempting to use the root account all the time on a single-user computer, it is unwise because Fedora assumes that you know what you're doing and won't ask for confirmation if you enter a dangerous command; it will just go ahead and execute it. If you're using the root account, an incorrect command can cause a lot more damage than the same command executed in a normal account.
Although you can directly log in as a root user, it's usually much safer to take on root privilege only when necessary, using the su (switch user) command:
$ su
Password:
root-password
#
The shell prompt will change to end in a pound sign ( # ) instead of a dollar sign ( $ ) when you are in root mode. Press Ctrl-D or type exit to drop superuser access and return to your regular shell prompt.
In this book, I'll use $ to indicate any normal user's prompt, user $ to specifically indicate user's prompt, and # to indicate the root prompt. Avoid entering commands as root unnecessarily!
4.1.1.5. Linux error messages
Many Linux commands will output a message only if something goes wrong. For example, if you try to remove a file using the rm command, no message will be displayed if the file is successfully deleted, but an error message will be generated if the file does not exist:
$ rm barbeque
rm: cannot remove Qbarbeque ': No such file or directory
Most error messages start with the name of the command that produced the message.
4.1.1.6. Logging out of a shell prompt
You can leave a shell by pressing Ctrl-D or typing exit . If you are using a terminal window and don't have any programs running, you can simply close the window using the X button on the title bar.
The shell prompt is managed by bash , the Bourne-again shell. bash got its name from the fact that it is a successor to the original Unix shell, sh , which is also known as the Bourne shell (after its author, Steve Bourne). bash is a command editor, command interpreter, job controller, and programming language.
When bash receives a command, it splits it into words and uses globbing to expand any ambiguous filenames. bash next checks to see if the first word is a built-in command. If not, it treats it as an external command or program and searches a list of directories to find that program. It executes that program, passing the other words to the program as arguments. Almost all Linux commands are external programs.
Linux commands generally accept three types of arguments:
Options
These start with a hyphen or double-hyphen ( - or -- ) and modify the way the command operates. For example, the ls (list-files) command will include hidden files in its output if the -a argument is given, and will list detailed information about files when the -l option is specified. These options may be used individually, used
