linux chapter 11 compress backup software

7/30/2019 Linux Chapter 11 Compress Backup Software

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Archiving, Compression, and

Managing Software Packages

Chapter Eleven


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Compressing Files

Compressing files

Useful way to use less space for rarely accessed data

Makes files smaller before transmitting them over network

gzip command Compress any file; best compression 60-70% of original size

Lempel-Ziv Compression

gzipv sample sample.gz

-v verbose option

zcat sample.gz to view compressed file contents

gunzip command

Uncompresses file compressed using gzip

gunzipv sample.gz

Alternative: gzipd sample.gz


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3

The gzip Utility (continued)


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Compressing Files

bzip2 command Compress any file; better compression than gzip

BurrowsWheeler transform and Huffman coding

bzip2v sample sample.bz2

-v verbose option

bzcat sample.bz2 to view compressed file contents

bunzip2 command

Uncompresses file compressed using gzip

bunzip2v sample.bz2

bzip2d sample.bz2


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The bzip2Utility (continued)


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The bzip2Utility (continued)


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System Backup

System backup: process whereby files are copied toan archive

Archive: location (file or device) that contains copy of

files Typically created by a backup utility

Should backup user files from home directories andany important system configuration files

Possibly files used by system services as well Several backup utilities available

tar, cpio, dump/restore, burning software


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System Backup (continued)


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Using tar for Archiving Files

tar archive

Tape Archive

Single file that can contain other files anddirectory structure

tar command

Create tar archive Specify files to be included in backup archive

on command line

Writes data to file name or device


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The tar Utility (continued)


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The tar Utility (continued)


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Using tar for Archiving Files

tar and compress an entire directorys contents

tarzcvf backup.tar.gz *

View contents of archive tarztvf backup.tar.gz *

tar to a tape device

tarcvf /dev/st0 *

Extract and uncompress

tarzxvf backup.tar.gz

Extract from a tape device tarxvf /dev/st0

Tarball archive and compressed .tar.gz or .tgz


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Using tar and cpio for Archiving Files

(continued) cpio command

Copy in and out

Similar to tar

Reads from STDIN channel for file names

Writes data back to STDOUT Examples

Archive

find /homeu horvathe | cpiovocBO horvathe.cpio

Extract

cpiovicBI horvathe.cpio

tar and cpio

Help create incremental or multilevel backup


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The cpio Utility (continued)


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The cpio Utility (continued)


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The dump/restore Utility

dump/restore: Used to back up files and

directories to device or file on filesystem

Works only with files on ext2 and ext3 filesystems

Designed to backup entire filesystems to an

archive

/etc/dumpdates: file used to store information

about incremental and full backups


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(continued)

Full backup: archiving all data on filesystem

Incremental backup: backs up only data that

has changed since last backup

Can perform up to nine different incremental

backups

dump command: create archives for full or

incremental backup

restore command: extract archives created

with dump


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(continued)

A sample back-up strategy


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(continued)


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Burning Software

tar, cpio, and dump utilities copy data to backupmedium in character-by-character or block-by-block

format

Typically used with tape, floppy, and hard disk media

Disc burning software: used to write files to CD orDVD media

Build CD or DVD filesystem, organize the data, and write it

all to CD or DVD

Ubuntu comes with k3b Disc Burner burning

software

Fedora comes with Brasero Disc Burner burning

software


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Managing Packages

Linux groups related files into packages for

easier management

Software package contains all files neededto install and use application

Red Hat Package Manager format

Abbreviated as rpm

Debian Package Manager format

Abbreviated as deb


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Managing Packages (continued)

Debian package format

Used by Debian Linux distributions

.deb file extension

dpkg old form for installing packages

apt Advanced Packaging Tool

dselect - utility manages Debian packages


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Synaptic Package Manager in

Ubuntu


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Using rpm to Manage Software

Packages rpm command-line utility maintains

database listing all software packages

installed on system Lists:

Files included in each package

Packages are dependent on other packages

Other information

rpm command

Install new software packages

Erase software acka es from s stem


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Packages (continued) Name of package file includes version

information

Example gedit-2.4.0-3.i386.rpm

Version 2.4.0

Release code 3

Platform i386


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Packages (continued) Rpm command options fall into categories

-q optionquery database and learn about packages

-i or -U optioninstall or upgrade package -e optionerase (uninstall) rpm package

-f option: together with q used to display the

package to which a specific file belongs

Install new rpm files either from: Linux CD-ROM

Internet


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Packages (continued) Install package zsh-4.2.0-1.i386.rpm

rpm -uvh /tmp/zsh-4.2.0-1.i386.rpm

Can use regular expression to specifypackage names

rpm utility maintains internal database of

keys

Key is part of encryption information used

to digitally sign rpm file


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Packages (continued) Fedora keys located in /usr/share/rhn

--import imports keys into rpm database

Check for keys

rpm --checksig -v packagefilename


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Installing Programs Using RPM

Packages in RPM format have filenames that

indicate hardware architecture for which the

software was compiled

End with .rpm extension

To install an RPM package, use i option to

rpm command

Command used to install, query, and remove RPM

packages


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(continued)


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(continued)


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(continued) Most RPM packages are located on Internet Servers

Called software repositories

yum command: used to search Internet software

repositories for RPM packages Installs dependent packages if necessary

yum install packagename command

yum update packagenamecommand

KPackageKit: graphical utility for installing or updating

packages


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(continued)

The KPackageKit utility


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alien

Converts RPM to DEB Packages

sudo aptitude install alien

Download rpm

sudo alien --scripts --to-deb avg75flm-r45-

a0973.i386.rpm avg75flm_r45-1_i386.deb

Coverts to deb generated

Install Debian package

sudo dpkg --install avg75flm_r45-1_i386.deb


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Repairing Package Manager

sudo aptitude install -c

Checks apt may need to be run if Synaptic

package manager hangs sudo aptitude install --fix-missing

sudo aptitude -f install

Fix packages; even sudo dpkg --configure -a

Attempts to install all partially installed packages


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APT Tools

aptitude install package-name

Installs a package

aptitude reinstall package-name

Reinstalls a package

aptitude remove package-name

Removes a package

aptitude purge package-name

Removes package and configuration files

aptitude show packagename

Displays information about the package, including dependencies.

May also use apt-get for many commands


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APT Tools aptitude update

Updates the list of available packages from the apt sources

aptitude upgrade

Upgrades installed packages to the most recent versions.

aptitude safe-upgrade The safest way to upgrade is to use the action 'safe-upgrade'. The

new action will upgrade a package only if it does not impact other

packages, i-e: if it is necessary to add or remove a dependency

package during upgrade, safe-upgrade won't upgrade


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APT Tools aptitude full-upgrade

Upgrades installed packages to the most recent versions.

aptitude will upgrade to the latest version of a package even if it is

necessary to add or remove dependencies.

aptitude clean

Deletes packages in the APT cache.


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APT Tools

apt-cache search keyword

Searches for packages that match a keyword

apt-cache depends packagename Display dependencies; packages that must be

installed before this package can be used.

aptitude search packagename

Searches for packages have the packagename


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Repositories

Sites where packages can be downloaded

/etc/apt/sources.list

# comment

deb executable

deb-src source code


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dpkg

Monitors which software packages are installed

Location of packages

Dependencies

Will not download packages from a repository

dpkg --list packagename.deb

Information about packages

dpkg --install packagename.deb

Install packages

dpkg -- purge packagename

Delete package and configuration files


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dpkg

dpkg --status packagename Displays information about an installed

package

dpkg --search packagename

Search for packages with a name


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Updating the System

Automatically Download upgrades or security fixes for key

operating system packages installed on system


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Software Updates in Ubuntu


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Updating the System

Automatically Red Hat Network

Download upgrades or security fixes for key

operating system packages installed on system Subscribe to Red Hat Network service

May be entitled to annual subscription as part of

purchase

Individuals can use for free


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Updating the System

Automatically (continued) Red Hat Network

Uses icon on Panel in GNOME or KDE to

indicate status Check mark in blue circle

Flashing exclamation point in red circle

To register, double-click network alert icon on

panel

To configure, right-click alert icon


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Updating the System

Automatically (continued) up2date utility

Manage updated software

Configure overall settings for Red HatNetwork

System Tools then Red Hat Network on

GNOME main menu Tabs

General

Retrieval/installation

Package exceptions

C ili S C d i t


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Compiling Source Code into

Programs Procedure for compiling source code into binary

programs standardized among most OSS developers

Source files are typically stored in a .tar.gz file

make command: looks for Makefile and it to compilethe source code into binary using compiler

Makefile: contains most of the information and commands

necessary to compile a program, as well as instructions for

use of commented areas

make install command: copies complied

executable programs to correct location

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