1-Accessing the Command Line
!
metacharacter that is used to expand previous commands without having to retype them
!historyCommandNumber
Execute a specific history entry
Virtual Console
One of multiple logical consoles that can each support an independent login session. If the graphical environment is available, it will run on the first virtual console in Red Hat Enterprise Linux 7. 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 pressingCtrl+Alt and pressing a function key (F2 through F6). Press Ctrl+Alt+F1 to return to the first virtual console and the graphical desktop.
Anything followed by ...
Represents an arbitrary-length list of items of that type
Workspaces
Separate desktop screens which have different application windows. Can be used to organize the working environment by grouping open application windows by task.
$
Shell prompt indicator showing user is running as regular user
window list
The bar that runs along the bottom of the screen. Provides an easy way to access, minimize, and restore all windows in the current workspace. On the right corner an indicator to tell the user which workspace they are on and how many are available.
Command
The name of a program to run.
Option
The part of the command line that adjusts the behavior of a command.
dash
also called the dock, this shows a configurable list of users favorite applications, running applications, and a grid button which can be used to select arbitrary applications
head -n 20
display the top 20 lines of a file
command --help
Causes command to print a description of what it does, a "usage statement" that describes the command's syntax
semicolon ;
Character to separate multiple commands on a single line
Ctrl+u
Clear from the cursor to the beginning of the command line
GNU Bourne-Again Shell (bash)
A program that interprets commands typed in by the user, an improved version of sh
Ctrl+Alt+F2-F6
Access text login prompt on a virtual console
passwd
Command to change the users password
date
Command to show current date and time
wc
Count lines, words and characters in a file
Ctrl+Right Arrow
Jump to the end of the next word on the command line
Enter
Key pressed to execute a command
Tab
Key pressed to quickly complete commands or filenames once they have typed enough to make it unique, if characters are not unique yet, pressing this key twice displays all commands that begin with the chars already typed
Multiple items separated by pipes |
Means only one of them can be specified
wc -w
Show number of words in a file
Activities Overview
Special mode that helps user organize windows and start applications. Shows the dash, windows overview, and workspace selector. Super key opens.
Applications > Utilities > Terminal or right click desktop or activities overview grid button
Starting a terminal
Prompt
The visual cue that indicates an interactive shell is waiting for the user to type a command.
Ctrl+k
Clear from the cursor to the end of the command line
Ctrl+Left Arrow
Jump to the beginning of the previous word on the command line
Ctrl+e
Jump to the end of the command line
date +%R
Show current time
wc -c
Show number of characters in a file
wc -l
Show number of lines in a file
Square brackets, [ ]
Surrounds optional items
Ctrl+Alt+UpArrow or Ctrl+Alt+DownArrow
Switching between workspaces sequentially
Argument
The part of the command line that specifies the target that the command should operate on.
file
This command scans the beginning of a file's contents and displays what type it is.
Places menu
This menu to the right of the Applications menu provides quick access through a graphical file manager to important menus in the user's home directory, to /, and to exports and file shares on the network.
+
This symbol before a date command argument specifies a format string
#
shell prompt indicator showing that user is running as superuser root
date +%x
Show current date
Terminal
An interface that provides a display for output and a keyboard for input to a shell session.
!stringcommand
Execute the most recent string command
desktop environment
Graphical user interface on a Linux System
Ctrl+a
Jump to the beginning of the command line
Ctrl+Alt+F1
Return to the first graphical console and the graphical desktop
Ctrl+r
Search the history list of commands for a pattern
top bar
The bar that runs along the top of the screen. It provides the Applications and Places menus and controls for volume, networking, calendar access, and selecting between keyboard input methods. Under the menu for the user's name are options to adjust account settings, lock the screen, switch users, log out or shut down.
Physical Console
The hardware display and keyboard used to interact with a system.
Shell
The interpreter that executes commands typed as strings.
history
displays a list of previously executed commands prefixed with a command number
tail
displays bottom 10 lines of a file
head
displays the top 10 lines of a file
message tray
provides a way to review notifications sent by applications or system components to GNOME. If a notification occurs, normally the notification first appears briefly as a single line at the bottom of the screen, and a persistent indicator appears in the lower right corner to inform the user of how many notifications have been recently received. It can be opened by pressing Super+m and closed by Esc or Super+m again.
Applications Menu
this menu on the top bar provides a way to start applications, categorized into submenus. The Activities Overview can also be started from this menu.