L11 Compression, System Backup, and Software Installation
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_____ is a process in which files are reduced in size by stripping out characters.
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Compression
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A _____ is a standard set of instructions used to compress a file.
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compression algorithm
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The _____ is the amount of compression occurring during compression in relation to the original file size.
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compression ratio
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State the three most common compression utilities.
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compress gzip bzip2
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T/F. The compress utility is one of the oldest compression utilities common to most UNIX and Linux systems. Its compression algorithm, which is called Adaptive Lempel-Ziv coding (LZW), has an average compression ratio of 40 to 50%.
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True
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To compress a file using the compress utility, you can specify the files to compress as arguments to the _____ command. Each file is renamed with a .Z filename extension to indicate that it is compressed.
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compress
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T/F. You can use the zmore and zless commands to view the contents of a compressed file page-by-page.
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True
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The _____ utility uses a Lempel-Ziv compression algorithm (LZ77) that varies slightly from the one used by the compress utility. Typically, this algorithm yields better compression than the one used by compress. The average compression ratio for gzip is 60 to 70%.
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GNU zip (gzip)
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The gzip utility uses the __________________________ filename extension by default and can control the level of compression via a numeric option (based on time needed to compress the file).
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...
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T/F. You can use the zcat and zmore commands to send the contents of a compressed file using the gzip utility to standard output.
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True
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The _____ command is used to decompress the .gz files.
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gunzip
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The _____ command is used to compress files using the Burrows-Wheeler Block Sorting Huffman Coding compression algorithm. It can't compress a directory full of files. The compression ratio is 50% to 75% on average.
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bzip2
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The filename extension given to a compressed file using bzip2 is __________________________.
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...
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T/F. The bzip2 utility can't use zcat and zmore to view files. Instead, the bzcat, bzmore and bzless command must be used.
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True
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The _____ command is used to decompress files compressed via bzip2.
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bunzip2
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The _____ is a process whereby files and directories are copied and stored at an alternative location.
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system backup
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______ are the backup copies of files and directories.
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Archives
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T/F. As a general rule of thumb, you should back up user files from home directories and any important system configuration files such as /etc/passwd.
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True
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There are several backup utilities available. State them.
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tar cpio dump/restore Disk-burning software
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The_____ utility is one of the oldest and most widely used backup utilities. It can create an archive in a file on a filesystem or directly on a device. It accepts options to determine the location of the archive and the action to perform on the archive.
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tape archive (tar)
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To create an archive called /backup.tar that contains the contents of the current directory and view the contents, you can use the commands:
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tar -cvf /backup.tar * ls -l /backup.tar
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T/F. The tar utility does not compress files inside the archive. Therefore, the time needed to transfer the archive across a network is high. To reduce transfer times, you can compress the archive using a compression utility before transmission.
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True
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T/F. Backing up files to a compressed archive on a filesystem is useful when transferring the archived data across a network. However, you can use tar to back up data directly to a device such as a tape.
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True
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The ____ utility is another common backup utility that uses options similar to the tar utility. It has some added features including long filenames and the ability to back up device files. It uses absolute pathnames by default when archiving.
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copy in/out (cpio)
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The _____ utility can be used to back up files and directories to a device or to a file on the filesystem. It only works with files on ext2 and ext3 filesystems.
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dump/restore
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T/F. The /etc/dumpdates is a file used to store information about incremental and full backups.
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True
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A _____ archives all of the data on the filesystem.
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full backup
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An _____ backs up only data that has changed since the last backup of any type.
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incremental backup
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The __________________________ command extracts the archives created with dump.
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...
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T/F. The tar, cpio and dump utilities copy data to a backup medium in a character-by-character or block-by-block format. It is typically used with tape, floppy and hard disk media.
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True
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_____ is used to write files to CD-RW or DVD-RW media. Fedora Core comes with the Brasero Disc Burner program.
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Burning software
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T/F. Software for Linux can consist of binary files and source code.
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True
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_____ are precompiled to run on certain hardware architectures.
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Binary files
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_____ must be compiled on the local architecture before it can be used.
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Source Code
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The _____ provides a standard format for distributing programs as well as a central database to store information about software packages installed on the system. It is used to install, query and remove packages.
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Package Manager
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The Red Hat Package Manager is the most common package manager used by Fedora Core Linux systems today.
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...
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The _____ is the most common package manager used by Debian-based Linux systems today. Ubuntu Linux uses this Package Manager.
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Debian Package Manager (DPM)
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T/F. The procedure for compiling source code into binary programs is standardized today among most Open Source Software (OSS) developers.
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True
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T/F. Because most source code comes in tarball format, you must uncompress and extract the files. This creates a subdirectory under the current directory containing the source code.
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True
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T/F. In addition, this directory typically contains a README file with information about the program and an INSTALL file with instructions for installation.
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True
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T/F. While inside the source code directory, the first step to installation is to run the configure program. This performs a preliminary check for system requirements and creates a list of what to compile inside a file called Makefile in the current directory.
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True
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T/F. Next you can type the make command, which looks for the Makefile file and uses the information in it to compile the source code into binary programs using the appropriate compiler program for the local hardware architecture.
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True
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T/F. After compilation, the binary files the program comprises remain in the source code directory. To copy the files to the appropriate location on the filesystem, such as a directory listed in the PATH variable, you must type make install.
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True
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The packages in RPM format have filenames that indicate the hardware architecture for which the software was compiled and end with the __________________________ extension.
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...
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T/F. To install an RPM package, use -i option with the rpm command.
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True
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After installation, the RPM database is updated to contain information about the installed package and files contained in it. List some useful options to use with the rpm command.
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-q option: query the full package name -i option: together with -q used to display full package information -f option: together with -q used to display the package to which a specific file belongs -e option: used to remove a package from the system
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Most RPM packages are located on Internet servers called __________________________.
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...
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The yum (Yellowdog Update Modular) command is used to search Internet software repositories for RPM packages. It downloads and installs the dependent packages if necessary.
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...
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T/F. KPackageKit is a graphical utility for installing or updating packages.
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True
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The DPM is similar to the RPM. However, it uses the __________________________ extension for its packages.
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...
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The __________________________ command can be used to install DPM packages that have been downloaded locally.
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...
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In addition, the __________________________ command can be used to download and install DPM packages from software repositories on the Internet and is analogous to the yum command for the RPM.
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...
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1. Most source code is available on the Internet in tarball format. True or False?
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True
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2. Which dump level indicates a full backup? a. 0 b. 9 c. 1 d. f
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a. 0
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3. Which filename extension indicates a tarball? a. .tar.gz b. .cpio c. .dump d. .tar
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c. .dump
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4. Files that have been compressed using the compress utility typically have the ______ extension. a. .tar.gz b. .gz c. .Z d. .bz2
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c. .Z
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5. The bzip2 and gzip utilities use similar compression algorithms. True or False?
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False
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6. When compiling source code into a binary program, which command does the compiling using the GNU C Compiler? a. tar b. ./configure c. make d. make install
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c. make
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7. The -9 option to the gzip utility results in a higher compression ratio. True or False?
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True
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8. You have created a full backup and four incremental backups. In which order must you restore these backups? a. 0, 1, 2, 3, 4 b. 0, 4, 3, 2, 1 c. 4, 3, 2, 1, 0 d. 1, 2, 3, 4, 0
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a. 0, 1, 2, 3, 4
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9. Which of the following commands extracts an archive? a. cpio -vocBL /dev/fd0 b. cpio -vicdu -I /dev/fd0 c. cpio -vicdu -O /dev/fd0 d. cpio -vti -I /dev/fd0
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b. cpio -vicdu -I /dev/fd0
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10. The Debian Package Manager (DPM) is the default package manager used by Fedora 13. True or False?
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False
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11. Which of the following commands can be used to list the files contained within an installed RPM package? a. rpm -qa packagename b. rpm -qi packagename c. rpm -ql packagename d. rpm -q packagename
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c. rpm -ql packagename
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12. When compiling source code into a binary program, which command copies compiled binary files to the correct location on the filesystem? a. tar b. ./configure c. make d. make install
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d. make install
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13. To install a new program from RPM software repositories on the Internet, you can use the yum update programname command. True or False?
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False
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14. Which file contains full and incremental backup information for use with the dump/restore utility? a. /etc/dumps b. /etc/dumpdates c. /etc/dumpfile d. /etc/dump.conf
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b. /etc/dumpdates
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16. What is the most common method for obtaining Linux software? a. CD-ROM b. floppy disk c. Internet download d. e-mail
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c. Internet download
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17. Which option to the rpm command can be used to remove a package from the system? a. r b. e c. u d. U
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b. e
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18. Which of the following commands creates an archive? a. tar -cvf /dev/fd0 b. tar -xvf /dev/fd0 c. tar -tvf /dev/fd0 d. tar -zcvf /dev/fd0 *
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d. tar -zcvf /dev/fd0 *
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19. When compiling source code into a binary program, which command performs a system check and creates the Makefile? a. tar b. ./configure c. make d. make install
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b. ./configure
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20. Which of the following commands can be used to list detailed information about a package such as its installation date and license? a. rpm -qa packagename b. rpm -qi packagename c. rpm -ql packagename d. rpm -q packagename
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b. rpm -qi packagename
