PACKAGE MANAGEMENT WITH APT-GET

Ubuntu features a comprehensive package management system for installing, upgrading, configuring, and removing software. In addition to providing access to an organized base of over 60,000 software packages for your Ubuntu computer, the package management facilities also feature dependency resolution capabilities and software update checking.

Several tools are available for interacting with Ubuntu’s package management system, from simple command-line utilities which may be easily automated by the system administrators, to a graphical interface which is easy to use by those new to Ubuntu.

Introduction

Ubuntu’s package management system is derived from the same system used by the Debian GNU/Linux distribution. The package files contain all of the necessary files, meta-data, and instructions to implement a particular functionality or software application on your Ubuntu computer.

Debian package files typically have the extension .deb, and usually exist in repositories which are collections of packages found online or on physical media, such as CD-ROM discs. Packages are normally in a pre-compiled binary format; thus installation is quick and requires no compiling of software.

Many packages use dependencies. Dependencies are additional packages required by the principal package in order to function properly. For example, the speech synthesis package festival depends upon the package alsa-utils, which is a package supplying the ALSA sound library tools needed for audio playback. In order for the festival to function, it and all of its dependencies must be installed. The software management tools in Ubuntu will do this automatically.

sudo su

In Linux (and Unix in general), there is a SuperUser named root. The Windows equivalent of the root is the Administrators group. The SuperUser can do anything and everything, and thus doing daily work as the SuperUser can be dangerous.

By default, the root account password is locked in Ubuntu. This means that you cannot log in as root directly or use the su command to become the root user.

The sudo command stands for "superuser do" .

sudo su

It will ask for a Linux password.

 Apt-Get

The apt-get the command is a powerful command-line tool, which works with Ubuntu's Advanced Packaging Tool (APT) performing such functions as installation of new software packages, upgrade of existing software packages, updating the package list index, and even upgrading the entire Ubuntu system.

Update the Package Index The APT package index is essentially a database of available packages from the repositories defined in the /etc/apt/sources.list file and in the /etc/apt/sources.list.d directory. To update the local package index with the latest changes made in the repositories, type the following

 

sudo apt-get update

 

Upgrade Packages

 Over time, updated versions of packages currently installed on your computer may become available from the package repositories (for example security updates). To upgrade your system, first, update your package index as outlined above, and then type:

 sudo apt-get upgrade

 

Aptitude

Launching Aptitude with no command-line options will give you a menu-driven, text-based front-end to the Advanced Packaging Tool (APT) system. Many of the common package-management functions, such as installation, removal, and upgrade, can be performed in Aptitude with single-key commands, which are typically lowercase letters.

Aptitude is best suited for use in a non-graphical terminal environment to ensure the proper functioning of the command keys. You may start the menu-driven interface of Aptitude as a normal user by typing the following command at a terminal prompt:

sudo aptitude 

When Aptitude starts, you will see a menu bar at the top of the screen and two panes below the menu bar. The top pane contains package categories, such as New Packages and Not Installed Packages. The bottom pane contains information related to the packages and package categories. 

 

Find Out Package Name and Description of Software

 

To find out the package name and its description before installing, use the ‘search‘ flag. Using “search” with apt-cache will display a list of matched packages with a short description. Let’s say you would like to find out the description of package ‘bluefish‘ , then the command would be.

 apt-cache search bluefish

 

Install a Specific Package

Installation of packages using the apt-get tool is quite simple. For example, to install the Bluefish HTML Editor, type the following:

 

sudo apt-get install bluefish

 

Install multiple packages

 You can add more than one package name along with the command in order to install multiple packages at the same time. For example, the following command will install packages ‘bluefish‘ and ‘leafpad‘.

 sudo apt-get install bluefish leafpad 

 

Remove a Package

Removal of a package (or packages) is also straightforward. To remove the package installed in the previous example, type the following:

 

sudo apt-get remove bluefish

 

Completely Remove Packages

 To remove software packages including their configuration files, use the ‘purge‘ subcommand as shown below.

 

sudo apt-get purge bluefish

 

Clean Up Disk Space

 The ‘clean‘ command is used to free up the disk space by cleaning retrieved (downloaded) .deb files (packages) from the local repository (/var/cache/apt/archives).

 

sudo apt-get clean

 

Download a Package without Installing

 Using the ‘download’ option, you can download any given package without installing it. For example, the following command will only download the ‘bluefish‘ package to the current working directory.

 

sudo apt-get bluefish

 

Check Broken Dependencies?

The ‘check’ a command is a diagnostic tool. It used to update the package cache and checks for broken dependencies.

 sudo apt-get check

 

MANUAL INSTALLATION OF APPLICATIONS

 Debian/Ubuntu package file has the .deb suffix. 

Download the package file wish to install and save it in a home folder.

 

sudo dpkg -i packagename.deb

 

E.g. sudo dpkg -i teamviewer*.deb If any dependency problem shows, apply force install command:

 

sudo apt-get install -f

REFERENCES

Apt-Get https://help.ubuntu.com/12.04/serverguide/apt-get.html

https://www.tecmint.com/useful-basic-commands-of-apt-get-and-apt-cache-for-package-management/