360 likes | 573 Views
Linux+ Guide to Linux Certification. Chapter 12 Compression, System Backup, and Software Installation. Objectives. Outline the features of common compression utilities Compress and decompress files using common compression utilities
E N D
Linux+ Guide to Linux Certification Chapter 12 Compression, System Backup, and Software Installation
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
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
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
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
The bzip2Utility • 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 bzip2Utility (continued) Table 12-3: Common options used with the bzip2 utility Linux+ Guide to Linux Certification, 2e
The bzip2Utility (continued) Table 12-3 (continued): Common options used with the bzip2 utility 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
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
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
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