Midterm Flashcards
Theory
The Bash Shell
A Linux command line program used to input instructions to the computer system. The default for Red Hat Enterprise Linux is the GNU Bourne-Again Shell (bash). Bash is an improved version of one of the most successful shells used on UNIX-like systems, the Bourne Shell (sh).
Shell Prompt
When a shell is used interactively, it displays a string when it is waiting for a command from the user. When a regular user starts a shell, the default prompt ends with a $ character. The prompt ends with a # if the shell is running as the superuser, root. This makes it more obvious that it is a superuser shell, which helps to avoid accidents and mistakes in the privileged account.
Terminal
Used to access the bash shell. Consists of keyboard and display. Can also be configured through serial ports.
Virtual Consoles
The physical console supports multiple virtual consoles which act like separate terminals. Each virtual console
supports an independent login session. If the graphical environment is available, it will run on the first virtual console. Five additional text login prompts are available on consoles two through six (or one through five if the graphical environment is turned off). With a graphical environment running, access a text login prompt on a virtual console by pressing Ctrl+Alt and pressing a
function key (F2 through F6).
Commands
Three basic parts: Command to run, Options to adjust command behaviour, and Arguments (typically targets of commands)
Usage Statement
(Printed when –help is used) A description of a command’s syntax and a list of options with descriptions of their function. Square brackets, [ ], surround optional items. Anything followed by … represents an arbitrary-length list of items of that type. Multiple items separated by pipes, |, means only one of them can be specified. Text in angle brackets, <>, represents variable data. Sometimes these variables are simply written in capital letters (e.g., FILENAME).
How to end a shell session
Execute the “exit” command, or press Ctrl+d
GNOME 3
Default desktop environment for Red Hat Enterprise Linux 7 (GUI on a Linux system)
GNOME Shell
Provides the core user interface functions for the GNOME desktop environment, and is highly customizable. By default, RHEL 7 users use the “GNOME Classic” theme for gnome-shell, which is similar to the GNOME 2 desktop environment. Another available option is the “modern” GNOME 3 theme used by the upstream GNOME project. Either theme can be selected persistently at login by selecting the gear icon next to the Sign In button when entering the user’s password.
GNOME Help
GNOME Help can be quickly started by pressing F1 in gnome-shell, by selecting Applications > Documentation > Help, or by running the yelp command.
Workspaces
Separate desktop screens which have different application windows. There are three methods for switching between workspaces. One method is to click the indicator in the right corner of the window list and select the desired workspace. Another, perhaps
the fastest, is to press Ctrl+Alt+UpArrow or Ctrl+Alt+DownArrow to switch between workspaces sequentially. A third is to switch to the Activities Overview and click the desired workspace. In Activities Overview, windows can be clicked and dragged between the current workspace and one of the others.
File System Hierarchy
All files on a Linux system are stored on file systems which are organized into a single inverted tree of directories, known as a file system hierarchy. This tree is inverted because the root of the tree is said to be at the top of the hierarchy, and the branches of directories and subdirectories stretch below the root. The directory / is the root directory at the top of the file system hierarchy. The / character is also used as a directory separator in file names.
Content Types
Static, Dynamic/Variable, Persistent, Runtime
Static Content
Content that remains unchanged until explicitly edited or reconfigured.
Dynamic/Variable Content
Content typically modified or appended by active processes.
