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

Linux+ Guide to Linux Certification, 2e2 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, 2e3 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, 2e4 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, 2e5 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, 2e6 The compress Utility (continued) Table 12-1: Common options used with the compress utility

Linux+ Guide to Linux Certification, 2e7 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, 2e8 The gzip Utility (continued) Table 12-2: Common options used with the gzip utility

Linux+ Guide to Linux Certification, 2e9 The gzip Utility (continued) Table 12-2 (continued): Common options used with the gzip utility

Linux+ Guide to Linux Certification, 2e10 The gzip Utility (continued) Table 12-2 (continued): Common options used with the gzip utility

Linux+ Guide to Linux Certification, 2e11 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, 2e12 The bzip2 Utility (continued) Table 12-3: Common options used with the bzip2 utility

Linux+ Guide to Linux Certification, 2e13 The bzip2 Utility (continued) Table 12-3 (continued): Common options used with the bzip2 utility

Linux+ Guide to Linux Certification, 2e14 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, 2e15 System Backup (continued) Table 12-4: Common tape device files

Linux+ Guide to Linux Certification, 2e16 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, 2e17 The tar Utility (continued) Table 12-5: Common options used with the tar utility

Linux+ Guide to Linux Certification, 2e18 The tar Utility (continued) Table 12-5 (continued): Common options used with the tar utility

Linux+ Guide to Linux Certification, 2e19 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, 2e20 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, 2e21 The cpio Utility (continued) Table 12-6: Common options used with the cpio utility

Linux+ Guide to Linux Certification, 2e22 The cpio Utility (continued) Table 12-6 (continued): Common options used with the cpio utility

Linux+ Guide to Linux Certification, 2e23 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, 2e24 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, 2e25 The dump/restore Utility (continued) Figure 12-1: A sample backup strategy

Linux+ Guide to Linux Certification, 2e26 The dump/restore Utility (continued) Table 12-7: Common options used with the dump/restore utility

Linux+ Guide to Linux Certification, 2e27 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, 2e28 Burning Software (continued) Figure 12-2: The X-CD-Roast program

Linux+ Guide to Linux Certification, 2e29 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, 2e30 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, 2e31 Compiling Source Code into Programs (continued) Figure 12-3: The rdesktop program

Linux+ Guide to Linux Certification, 2e32 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, 2e33 Installing Programs Using RPM (continued) Figure 12-4: The bluefish program

Linux+ Guide to Linux Certification, 2e34 Installing Programs Using RPM (continued) Table 12-8: Common options used with the rpm utility

Linux+ Guide to Linux Certification, 2e35 Installing Programs Using RPM (continued) Table 12-8 (continued): Common options used with the rpm utility

Linux+ Guide to Linux Certification, 2e36 Installing Programs Using RPM (continued) Figure 12-5: Configuring Fedora core software packages after installation