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Using a Linux Desktop Environment
- Used more by regular user
- Set of programs that control screen displays
- Small utilities programs to perform tasks:
- –Managing files
- –Setting permissions
- –Administering users
- –Changing configuration settings
- –Configuring desktop settings and much more
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KDE
- K Desktop Environment
- www.kde.org
- Default for Mandriva and SUSE
- Many powerful tools
- Built using Qt widget set
- Qt widget set
- –Application framework for developing application software with a Graphical User Interface
- –Can develop command line programs as well
- –Open Source–Standard language C++, but supports others
- KDE most like traditional desktops
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GNOME
- GNU Network Object Model Environment
- www.gnome.org
- Rival to KDE
- Default for Fedora and Debian
- Built using GIMP Tool Kit (GTK+)
- GIMP Tool Kit (GTK+) widget set
- –Application framework for developing application software with a Graphical User Interface
- –Can develop command line programs as well
- –Open Source
- –Language support C++, Java, Perl, Python, Ruby + others
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LXDE
- Lightweight X11 Desktop Environment
- www.lxde.org
- Intended to consume few resource
- Good for old less powerful systems
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Unity
- Publisher of Ubuntu release this desktop in 2010
- Similar to GNOME
- Good for inexperienced users
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Xfce
- www.xfce.org
- Intended to consume few resource
- Build using Gimp TK
- Very configurable
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Build-Your-Own desktop environment
- Build a desktop from component you like
- Need a Windows Manager (many available)
- Need other components like File Manager and productivity tools
- Not suited for the average users
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Launching Programs
- Desktop Menus
- –Available along the top, bottom, or sides of screen
- –Access to preselected applications
- –Add to or remove from
- Desktop Icons
- –Place commonly used application icons on desktop
- –Quick access
- Panels
- –Usually located on sides of the screens
- –Common application appear there
- Context Menus
- –Right click in an used part of screen to obtain a context menu
- –Provide a variety of options
- Searching for Programs
- –Some desktop provide a prominent search feature (GNOME)–Used to find programs by name–Use wildcards
- Terminals
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Using a File Manager
- Many available for Linux
- GNOME
- –Nautilus
- –Default for GNOME
- –Similar to other file managers in different O/S’s
- –Icon resembles a “Filing Cabinet”
- –Found in “Favorites” panel or “Computer” icon on desktop
- Location may vary depending on distribution or version
- –Automount – file manager automatically is launched -Available when a USB device is inserted
- –Different sections of the display- Left side displays series of locations
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File Manager Categories
- –User’s Home Directory–Desktop–File System–Network–Other file systems Included disk partitions
- –Trash (Recycle Bin)–Documents–Music–Pictures –Videos–Downloads and more
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Web Browsers
- Chrome
- –Technical commercial software but download for free
- FireFox
- –Most popular for Linux
- –Can consume resources
- Web
- –Originally called “Epiphany”
- –wiki.gnome.org/Apps/Web
- –lightweight
- Konqueror
- –KDE
- –Web browser and file manager
- Lynx
- –Text based
- Opera
- –Commercial (download for free)
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Web Browsers Problems
- –Web sites log user access data (Marketing/Junk)
- –Dynamic Web sites can download Java type program to local machine (can be used to deliver Malware)
- –Malicious web site can trick user into giving up sensitive data
- –Some web sites are not secure (https)
- –Passwords on web site may not be secure
- Hard to remember all logins for different sites
- Some browsers remember logins (Facebook)
- Vulnerable to theft or loss
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Email Clients
- –Read and write emails
- –Requires a email server
- –Mailbox locations:
- On local device: POP3
- On Server: IMAP
- Evolution: projects.gnome.org/evolution
- GUI email client
- Groupware and scheduling features
- KmailKDE: userbase.kde.org/Kmail
- Also can be used with other desktops
- mutt: www.mutt.org
- Text based
- Thunderbird: www.mozilla.org/thunderbird/
- Associated to Firefox Web browser
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GNOME Office
- –live.gnome.org/gnomeOffice
- –AbiWord: word processor
- –Evince: document viewer
- –Evolution: groupware and Email client
- –Gnumeric: spreadsheet
- –Inkscape: Vector graphics and presentation creation
- –Ease: presentation
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Calligra
- –Split from KDE office suite
- –www.calligra.org
- –Word processor, Presentation, Spreadsheet, Flowcharting, Database
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LibreOffice
- –Forked from OpenOffice
- –Becoming very popular with Linux users
- –Writer: word processor
- –Calc: spreadsheet
- –Impress: presentation
- –Base: database
- –Draw: vector graphics
- –Math: equation editor
- –May be slow on older systems
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Apache OpenOffice
- –Corporate sponsor Oracle stopped supporting development
- –Donated to Apache group
- –Has a full suite of applications
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Using Multimedia Applications
- Audacity
- Blender
- GIMP
- ImageMagick
- HandBrake
- MythTV
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Cloud Computing
- Offerings
- –Private cloud
- –Public cloud
- –Hybrid cloud
- Services
- –SaaS (Software as a Service)
- On-demand software
- Application and Database software
- –PaaS (Platform as a Service)
- Operating Systems, Database, Web Servers
- –IaaS (Infrastructure as a Service)
- Physical computing resources, Virtualization etc
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Android
- Linux based O.S.
- Different applications than on desktop or server
- “apps” small programs for mobile devices
- Are small usually commercial
- Provide quick and specialized computation
- Download “apps” using app called “Market”
- market.android.com
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Linux server
- Linux is a powerful O.S. for running server programs
- Wide variety of server programs
- Many Network Protocols
- Protocols are defined by RFC (Request for Comments)
- –RFC have a number associated i.e. RFC1035 for DNS
- –Ports are used to transfer data: 0-65535 ports
- –Ports and their use are found in /etc/services
- –Servers attach to a port number and receives all incoming requests on that port
- DNS, DHCP, Apache, D/B
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Common Network Ports
- 22 SSH OpenSSH
- 23 Telnet telnetd
- 53 DNS dnsmasq, named
- 80 HTTP Apache, NGINX
- 118 SQL MySQL, PostgreSQL, MariaDB
- 443 HTTPS Apache, NGINX
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Installing and Launching Servers
- Usually via configuration file(s)
- Service in Linux is called Daemon
- Daemons started at boot time or when needed
- Daemons run in background
- Scripts used to launch daemon
- systemd - system and services manager Directory structure for scripts: sysVinit /etc/init.d/rc.d
- Directory structure many change depending upon distribution
- Super Server:xinetd or inetd
- Can control specific daemons
- Can provide some security
- Systemctl start httpd
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Compiled vs Interpreted
- Complied: - Convert source code into machine code
- Compilation could take awhile depending on program size
- May fail because of syntax errors
- Even if compiles successfully no guarantee program will function as required
- Interpreted: Converted to machine code when the program is run
- Line by line bases
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Assembly Language
- Low-level language
- Requires a good deal of skill
- Produces very compact and efficient programs
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C
- Important language for Linux
- Most of the Kernel is written in C
- Fairly efficient
- Filenames that end in .c (main source code) or .h (header files)
- Compiled using “gcc” compiler
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Common Programming Languages
- C++: Extension to C that adds Object-Oriented features
- Different file extensions .cc, .cpp., .cxx
- Java: Created by Sun Microsystems (owned by Oracle)
- Cross between compiled and interpreted
- Popular for web site development
- Perl: Interpreted language
- Used to manipulate text
- PHP: PHP Hypertext Preprocessor – interpreted language
- Used on Web Servers for dynamic content
- Shopping carts, dynamic logins
- Python: Interpreted language
- Support OOP
- Shell Scripting: Many different shells
- BASH very common
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Identifying Common Package Tools
- dpkg Debian
- rpm Redhat, CentOS + others
- apt-get Debian
- yum Redhat, CentOS + others
- Fedora working on DNF new package manager
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