System Ad

• Software


  A series of related instructions that tells the computer what task(s) to do and how to perform them
• Categories of software

  • System software
  • Application software
• System software


  Consists of the programs that control or maintain the operations of the computer and its devices
• Types of system software

  • Operating system
  • Utility program
• Operating system


  A set of programs that coordinates all the activities among computer hardware devices
• Utility program


  Allows a user to perform maintenance-type tasks usually related to managing a computer, its devices, or its programs
• Application software


  Consists of programs designed to make users more productive and/or assist them with personal tasks
• Factors to consider before installing software

  • Necessity
  • Requirements
  • Support
• A package manager is a program used to install, update, upgrade, or remove software
• Commonly used package managers in Linux

  • rpm (Red Hat Package Manager)
  • yum (Yellowdog Updater Modifier)
  • apt (Advanced Packaging Tool)
• Syntax for installing an rpm file

  rpm [option] file(s)
• RPM Installation and Upgrade Options

  • --excludedocs
  • --force
  • --ignoresize
  • --ignorearch
  • --includedocs
  • --nosignature
  • --nodeps
• Package dependencies


  Software libraries required to complete the installation of a given piece of software
• Parts of the yum instruction

  1. Command: install, update, remove, list

  2. Package Name: a software title

  3. Options
• Sample usages of yum

  • yum install emacs
  • yum update httpd
  • yum list *gnome*
  • yum list gimp[0-9]
• Additional yum Commands

  • check-update
  • clean
  • downgrade
  • groupinstall, grouplist, groupremove, groupupdate
  • info
• Software Maintenance for rpm

  Commands used in upgrading: -U (upgrade), -F (freshen)
• Options for rpm -U and -F commands

  • --replacepkgs: Forces the installation of the package during the upgrade even if that particular package already exists
  • --replacefiles: Forces the installation of files that already exist
  • --oldpackage: Downgrades from the currently installed package to a previous one
  • --force: Performs all the above options
• Software Maintenance for yum

  Options used in updating: check-update, downgrade, groupupdate, reinstall, update, update-to, upgrade, upgrade-to
• apt package manager in Debian Linux


  The primary program for software installation is called apt-get
• apt-get syntax

  apt-get [options] command package(s)
• Possible apt-get commands

  • install
  • remove
  • update
  • upgrade
  • dist-upgrade
• Additional apt Programs

  • apt-cache: Used to query the APT package cache
  • apt-file: Used to examine a package to identify the specific files that are included
  • apt-secure: Used to ensure the integrity and authenticity of a package through digital signature checking
• In rpm, the command used to remove a package is -e or --erase
• In yum, the syntax used in removing a package is: yum remove packagename
• An operating system (OS) is the sum of all programs required to operate a computer and control and monitor application programs
• UNIX was originally written in the programming language C and is mainly used for scientific-technical applications on mainframes and workstations
• Linux is a family of UNIX-like open-source operating systems developed by Linus Torvalds
• The Linux Kernel is the main component of a Linux OS
• A Linux distribution (distro) is a collection of software on top of a Linux kernel
• A distro aims to provide a common look and feel, secure and easy software management, and often a specific operational purpose
• Shells are interfaces to the operating system, providing necessary instructions and operations
• Forms of shells

  • GUI (Graphical User Interface)
  • CLI (Command Line Interface)
• New users will pick up a GUI much faster than a CLI
• CLI users have more control over the file system and operating system, and tasks become simple through scripting
• GUI users can do only simple and limited tasks not flexible enough for controlling the system
• Linux Desktop Environments

  • GNOME
  • KDE
  • Xfce
• GNOME was once the most popular Linux desktop environment and was used by default on Ubuntu, Fedora, Debian, and most other big Linux distributions
• KDE has always been more complex than GNOME, packing in many more configuration options and features
• Xfce is a more lightweight desktop environment, very similar to GNOME