Bài giảng Quản trị Linux: Package management, Ubuntu - Đặng Thanh Bình

Bài giảng Quản trị Linux cung cấp kiến thức cơ bản về package management và Ubuntu. Nội dung chính trong chương này gồm có: Introduction, dpkg, apt-get, aptitude, automatic updates, repository config. Mời các bạn cùng tham khảo.

Đặng Thanh Bình

Package Management - 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

DPKG

• Many files are automatically generated during the package install process, and even though they are on the filesystem, dpkg -S may not know which package they belong to.

• For example using dpkg -r zip will remove the zip package, but any packages that depend on it will still be installed and may

no longer function correctly

APT-GET

• The apt-get 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 of the package list index

– Upgrading the entire ubuntu system

• Install a Package

sudo apt-get install nmap

• Remove a Package

sudo apt-get remove nmap

• Multiple Packages: You may specify multiple packages to be installed or removed, separated

by spaces

• Adding the purge option to apt-get remove

will remove the package configuration files as well

• 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

– To update the local package index with the latest changes made in the repositories, type the following:

sudo apt-get update

• Actions of the apt-get command, such as installation and removal of packages, are logged in the /var/log/dpkg.log log file

• For further information about the use of APT, read the comprehensive Debian APT User Manual or type:

apt-get help

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 graphical terminal environment to ensure proper functioning of the command keys

non-• Start the menu-driven interface of Aptitude

as a normal user by typing the following command at a terminal prompt:

sudo aptitude

Command Line Aptitude

• To install the nmap package with all necessary dependencies, as in the apt-get example, you would use the following command:

sudo aptitude install nmap

• To remove the same package, you would use the command:

sudo aptitude remove nmap

AUTOMATIC UPDATES

• The unattended-upgrades package can be used to automatically install updated packages, and can be configured to update all packages or just install security updates

• First, install the package by entering the following in a terminal:

sudo apt-get install unattended-upgrades

Automatic Updates

• To enable automatic updates, edit

/etc/apt/apt.conf.d/10periodic and set the appropriate apt configuration options:

• Configuring Unattended-Upgrade::Mail

in upgrades will enable unattended-upgrades

/etc/apt/apt.conf.d/50unattended-to email an administra/etc/apt/apt.conf.d/50unattended-tor detailing any packages that need upgrading or have problems

• To install the apticron package

sudo apt-get install apticron

• Edit /etc/apticron/apticron.conf, to set the email address and other options:

EMAIL="root@example.com"

REPO MANAGEMENT

What is a repository?

● A software repository is a storage location from

which software packages are retrieved for

Components of repositories?

● Four separate areas or "components", according to – The level of support offered by Ubuntu and whether or not the program in question complies with Ubuntu's Free Software

Philosophy.

● Including

– Main - Officially supported software.

– Restricted - Supported software that is not available under a

completely free license.

– Universe - Community maintained software, i.e not officially

supported softs.

– Multiverse - Software that is not free

● The Ubuntu Install CDs contain software from the

"Main" and "Restricted" components

Where are they stored?

● Apt stores a list of repositories or software channels in the file

deb http://ch.archive.ubuntu.com/ubuntu/ saucy main  restricted

deb­src http://ch.archive.ubuntu.com/ubuntu/ saucy  main restricted

#

Add Universe & Multiverse Repos

● Two ways

1) Uncomment related lines

● deb http://us.archive.ubuntu.com/ubuntu/  saucy universe

● deb­src  http://us.archive.ubuntu.com/ubuntu/ 

saucy universe

● deb http://us.archive.ubuntu.com/ubuntu/  saucy­updates universe

● deb­src  http://us.archive.ubuntu.com/ubuntu/ 

saucy­updates universe

Add Universe & Multiverse Repos

● Two ways

2) Use the add-apt-repository command If your release is 'saucy':

● sudo add­apt­repository "deb 

http://us.archive.ubuntu.com/ubuntu/ saucy  universe multiverse"

– Type lsb_release -sc to find out your release Repeat the

commands with "deb-src" instead of "deb" in order to install the source files.

– Don't forget to retrieve the updated package lists:

● sudo apt­get update

Adding Partner Repositories

● Uncommenting the following lines in

/etc/apt/sources.list file:

deb http://archive.canonical.com/ubuntu saucy  partner

deb­src http://archive.canonical.com/ubuntu  saucy partner

● Then update as before:

sudo apt­get update

● Note: this repository is NOT open source

Adding Launchpad PPA Repos

Adding Launchpad PPA Repos

● Use add-apt-repository Similar to "addrepo" on Debian.

● sudo add-apt-repository ppa:<repository-name>

● Example: sudo add-apt-repository ppa:nhandler/ppa

● The command updates your sources.list file or adds/edits files under sources.list.d/

● If a public key is required and available it is automatically downloaded and registered.

● Should be installed by default On older or minimal

Ubuntu releases, you may have to install

software-properties-common and/or python-software-properties

first

– sudo apt-get install python-software-properties

Adding ISO image to be Repos

● Check apt-cdrom command

sudo mkdir /aptoncd­mountpoint

sudo mount /media/USB/aptoncd.iso ~/aptoncd­ mountpoint ­oloop

sudo apt­cdrom ­d=/aptoncd­mountpoint add

Graphical UI

● https://help.ubuntu.com/community/Repositories/ Ubuntu