Linux introduction Class 03 of 03.

1. ACE Course CT01558
Linux Introduction
Linux GUI & Command Tools

2.  X, DM, KDE and GNOME
 Other X Graphical User Interfaces
 Command Line Tools
 Shells, bash options, shell scripts
 Basic administration
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Agenda
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3.  X11, or “X Window System” is the a distributed
client/server software as well as protocol
 http://en.wikipedia.org/wiki/X_server
 Display Manager
 Controls WHO logs into display
 If GUI crashes, it restarts itself again!
 In most distributions, you can’t login as root to DM
 Each GUI has its version: KDM, GDM, MDM, …
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X & Display Managers

4.  Controls the placement & appearance of application
windows (frames, titles, icons)
 Metacity in GNOME
 KWin in KDE
 Xfwm in Xfce
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Window Managers

5.  Provide additional functionality to GUI with:
 Control panel
 cut & paste
 trash can
 file manager
 multimedia tools, music & wallpapers!
 notepad, calendar, calculator
 shared libraries for those programs
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Desktop Environments (DE)

6.  Most Popular Desktop Environments are:
 KDE http://kde.org/
 GNOME http://www.gnome.org/
 Xfce http://xfce.org/
 Much more exist!
 Common Desktop Environment (CDE)
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Linux Desktop Environments

7. 7
Basic Linux Usage
Accessing a terminal in a GUI environment

8.  Graphical interface
 Start GUI environment on top of BASH shell
 Or, switch to a graphical terminal
e.g., GNOME Display Manager (gdm)
Graphical Interface

9. Shells, Terminals, and the Kernel
 From the local server, use key combinations to change to
separate terminal
 Command-line terminal may be accessed from GUI
environment
 Command line prompt:
 Root user: #
 Regular user: $

10.  Commands: indicate name of program to execute
 Case sensitive
 Options: specific letters starting with “-” appearing
after command name
 Alter way command works
 Arguments: specify a command’s specific working
parameters
Basic Shell Commands

11.  ls command: List the files in a directory
 May pass an argument indicating the directory to be
listed
 –F option: Argument to indicate file types
 –l option: Argument to list long file listings
Linux+ Guide to Linux Certification, 3ed 11
Listing Files

12. Basic Shell Commands (continued)
Some common Linux commands

13. Shell Metacharacters
 Metacharacters: characters with
a special meaning
 e.g., $
 Refers to a variable
 Avoid use of metacharacters
when typing commands unless
using their special functionality
 Single quotation marks ‘ ’ protect
metacharacters from being
interpreted specially by the shell

14.  A shell script is a script written for the shell
 Operations: backups, file manipulation, program
execution, and printing text
 A script needs to be “flagged” as an executable “x”
with the chmod command
 If you are running a script from current directory it
needs to be preceded by “./”
Shell Scripts

15. Getting Command Help
 Manual (man) pages: most common form of
documentation for Linux commands
 type “man” followed by command name
 contains different sections
 Searchable by keyword
 Info pages: set of local, easy-to-read command syntax
documentation
 type “info” followed by a command name

16.  Start/Stop/Reboot Server
 Backup critical or User files
 Install NEW software or services
 Update EXISTING software
 Add/Remove users
 Troubleshoot
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Basic Administration

17. Linux#3 - Commands 17
System Stop or Reboot
 To reboot:
 shutdown –r
 reboot
 init 6
 To halt:
 shutdown –s
 halt
 init 0
 You must be administrator!
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18.  Adds
functionality to
your system,
example:
install LibreOffice
or MySQL
 From Command
line mode:
 sudo apt-get
mysql
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Install Software

19.  Keeps your
system safe and
bug-free
 From Command
line mode:
 sudo apt-get
update
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Update Software

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Monitoring & Process Control
 top – displays top processes
 uptime + ps = w
 ps ax – list of all running processes
 nice PID priority – changes priority level
 Default priority is 10, it can be changed
 from -20 (highest priority) to 19 (lowest)
 kill –signal PID
 killall process
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21.  useradd <username>
 passwd <username> //changes password for a user
 userdel <username>
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User Maintenance

22.  Installation Fails
 Server crashes
 Service(s) not running
 Read LOGS! /var/log/messages
 Restart in single user mode [init S]
 Check file system for errors
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Troubleshooting

23.  KDE and GNOME
 Other X Graphical User Interfaces
 Command Line Tools
 Shells, bash options, shell scripts
 Basic administration
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Summary
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24. Questions???