Linux+ Guide to Linux Certification Chapter 12 Compression, System Backup, and Software Installation

Linux+ Guide to Linux Certification, 2e Objectives Outline the features of common compression utilities Compress and decompress files using common compression utilities Perform system backups using the tar, cpio, and dump commands View and extract archives using the tar, cpio, and restore commands Linux+ Guide to Linux Certification, 2e

Objectives (continued) Use burning software to back up files to CD-RW and DVD-RW Describe common types of Linux software Compile and install software packages from source code Use the Red Hat Package Manager to install, manage, and remove software packages Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e Compression Compression: Process in which files are reduced in size by a compression algorithm Compression algorithm: Set of instructions used to systematically reduce a file’s contents Compression ratio: Amount of compression occurring during compression Three most common compression utilities: Compress gzip bzip2 Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e The compress Utility compress command: Used to compress files using Lempel-Ziv compression algorithm zcat command: Used to view contents of an archive created with compress or gzip to Standard Output uncompress command: Used to decompress files compressed by compress command Linux+ Guide to Linux Certification, 2e

The compress Utility (continued) Table 12-1: Common options used with the compress utility Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e The gzip Utility GNU zip (gzip): Used to compress files using Lempel-Ziv compression algorithm Varies slightly from algorithm used by compress Typically yields better compression than compress Uses .gz filename extension by default Can control level of compression gunzip command: Used to decompress .gz files Linux+ Guide to Linux Certification, 2e

The gzip Utility (continued) Table 12-2: Common options used with the gzip utility Linux+ Guide to Linux Certification, 2e

The gzip Utility (continued) Table 12-2 (continued): Common options used with the gzip utility Linux+ Guide to Linux Certification, 2e

The gzip Utility (continued) Table 12-2 (continued): Common options used with the gzip utility Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e The bzip2 Utility bzip2 command: Used to compress files using Burrows-Wheeler Block Sorting Huffman Coding compression algorithm Cannot compress directory full of files Cannot use zcat and zmore to view files Must use bzcat command Compression ratio is 50% to 75% on average bunzip2 command: Used to decompress files compressed via bzip2 Linux+ Guide to Linux Certification, 2e

The bzip2 Utility (continued) Table 12-3: Common options used with the bzip2 utility Linux+ Guide to Linux Certification, 2e

The bzip2 Utility (continued) Table 12-3 (continued): Common options used with the bzip2 utility Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e System Backup System backup: Process whereby files are copied to an archive Archive: Location (file or device) that contains copy of files Typically created by a backup utility Should backup user files from home directories and any important system configuration files Possibly files used by system services, as well Several backup utilities available tar, cpio, dump/restore, burning software Linux+ Guide to Linux Certification, 2e

System Backup (continued) Table 12-4: Common tape device files Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e The tar Utility Tape archive (tar) utility: One of oldest and most common backup utilities Can create archive in a file on a filesystem or directly on a device Accepts options to determine location of archive and action to perform on archive Linux+ Guide to Linux Certification, 2e

The tar Utility (continued) Table 12-5: Common options used with the tar utility Linux+ Guide to Linux Certification, 2e

The tar Utility (continued) Table 12-5 (continued): Common options used with the tar utility Linux+ Guide to Linux Certification, 2e

The tar Utility (continued) tar utility does not compress files inside archive Time needed to transfer archive across a network is high Can compress archive Backing up files to compressed archive on a filesystem is useful when transferring data across a network Ill suited to backing up large amounts of data for system recovery Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e The cpio Utility Copy in/out (cpio): Common backup utility Includes options similar to tar utility Has added features Ability to back up device files Long filenames Uses absolute pathnames by default when archiving Linux+ Guide to Linux Certification, 2e

The cpio Utility (continued) Table 12-6: Common options used with the cpio utility Linux+ Guide to Linux Certification, 2e

The cpio Utility (continued) Table 12-6 (continued): Common options used with the cpio utility Linux+ Guide to Linux Certification, 2e

The dump/restore Utility dump/restore: Used to back up files and directories to device or file on filesystem Works with files on ext2 and ext3 filesystems /etc/dumpdates: File used to store information about incremental and full backups Linux+ Guide to Linux Certification, 2e

The dump/restore Utility (continued) Full backup: Archiving all data on filesystem Incremental backup: Backs up only data that has changed since last backup restore command: Extract archives created with dump Linux+ Guide to Linux Certification, 2e

The dump/restore Utility (continued) Figure 12-1: A sample backup strategy Linux+ Guide to Linux Certification, 2e

The dump/restore Utility (continued) Table 12-7: Common options used with the dump/restore utility Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e Burning Software tar, cpio, and dump utilities copy data to backup medium in character-by-character or block-by-block format Typically used with tape, floppy, and hard disk media Burning software: Used to write files to CD-RW or DVD-RW media Red Hat Fedora Core 2 comes with X-CD-Roast Linux+ Guide to Linux Certification, 2e

Burning Software (continued) Figure 12-2: The X-CD-Roast program Linux+ Guide to Linux Certification, 2e

Software Installation Software for Linux can consist of: Binary files precompiled to run on certain hardware architectures Source code, which must be compiled Typically distributed in tarball format Package manager: System that defines standard package format Used to install, query, and remove packages Red Hat Package Manager (RPM): Most common package manager used by Linux systems today Linux+ Guide to Linux Certification, 2e

Compiling Source Code into Programs Procedure for compiling source code into binary programs standardized among most OSS developers GNU C Compiler (gcc): Command used to compile source code into binary programs After compilation, must move program files to appropriate directory Makefile: Contains most of information and commands necessary to compile program Linux+ Guide to Linux Certification, 2e

Compiling Source Code into Programs (continued) Figure 12-3: The rdesktop program Linux+ Guide to Linux Certification, 2e

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 Linux+ Guide to Linux Certification, 2e

Installing Programs Using RPM (continued) Figure 12-4: The bluefish program Linux+ Guide to Linux Certification, 2e

Installing Programs Using RPM (continued) Table 12-8: Common options used with the rpm utility Linux+ Guide to Linux Certification, 2e

Installing Programs Using RPM (continued) Table 12-8 (continued): Common options used with the rpm utility Linux+ Guide to Linux Certification, 2e

Installing Programs Using RPM (continued) Figure 12-5: Configuring Fedora core software packages after installation Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e Summary Many compression utilities are available for Linux systems; each uses a different compression algorithm and produces a different compression ratio Files can be backed up to an archive using a backup utility Tape devices are the most common medium used for archives To back up files to CD-RW or DVD-RW, use burning software instead of a backup utility Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e Summary (continued) tar is the most common backup utility used today Creates compressed archives called tarballs Source code for Linux software can be obtained and compiled afterward using the GNU C Compiler Most source code is available in tarball format via the Internet Linux+ Guide to Linux Certification, 2e

Linux+ Guide to Linux Certification, 2e Summary (continued) Package Managers install and manage compiled software of the same format The Red Hat Package Manager is the most common package manager available for Linux systems today Linux+ Guide to Linux Certification, 2e