COMP1298-01 Networks and Applications, Ch 11
What option can be added to the rpm command to upgrade a specified package only if an older version exists on the system?
-F
When used with the compress command, what option below can be used to compress symbolic links?
-f
When used with the uncompress command, what option displays the contents of the compress file to Standard Output?
-f
Select the option that, when used with the gzip command, causes the compression ratio for files that have been compressed to be listed:
-l
When using the compress utility, each file specified for compression is renamed with what extension?
.Z
What device file below indicates the first ATAPI IDE tape device (nonrewinding)?
/dev/nht0 slash, dev, slash, nht0
The Adaptive Lempel-Ziv compression algorithm used by the compress utility is capable of an average compression ratio of what percent?
40-50
If no level of compression is specified, the gzip command assumes what compression level?
6
What is the average compression ratio for the gzip utility using the LZ77 compression algorithm?
60%-70%
When backing up a system, what type of files should be archived, and what types should not?
A typical Linux system can include hundreds of thousands of files, but you don't have to include all of them in an archive. For example, you don't have to include temporary files in the /tmp and /var/tmp directories, nor do you need to include any cached Internet content found in the .mozilla directory (if you use the Mozilla Firefox Web browser) under each user's home directory. As a rule of thumb, you should back up user files from home directories and any important system configuration files such as /etc/passwd. In addition to this, you might want to back up files used by system services. For example, you need to back up Web site files if the Linux computer is used as a Web server. Programs such as grep and vi need not be backed up because they can be restored from the original installation media in the event of a system failure.
Most Linux distributions make use of what package manager?
RPM
In order to download DPM packages, what command should be used below?
apt-get
Describe the difference between full and incremental backups. Explain how both might be used to implement a back-up strategy, mentioning how the dump/restore utility can assist in this implementation. Provide an example.
Although the dump/restore utility can be used to back up only certain files and directories, it was designed to back up entire filesystems to an archive and keep track of these filesystems in a file called /etc/dumpdates. Because archiving all data on a filesystem (known as a full backup) might take a long time, you can choose to perform a full backup only on weekends and incremental backups each evening during the week. An incremental backup backs up only the data that has been changed since the last backup. In the case of a system failure, you can restore the information from the full backup and then restore the information from all subsequent incremental backups in sequential order. You can perform up to nine different incremental backups using the dump/restore utility; number 0 represents a full backup, whereas numbers 1 through 9 represent incremental backups. Suppose, for example, that you perform a full backup of the /dev/sda3 filesystem on Sunday, perform incremental backups from Monday to Wednesday, and on Thursday the /dev/sda3 filesystem becomes corrupted. After the filesystem has been re-created, you should restore the full backup (0) followed by the first incremental backup (1), the second incremental backup (2), and the third incremental backup (3) to ensure that data has been properly recovered.
What types of media are commonly used for archives? What type of media is most commonly used for archiving on Linux systems?
You can create archives on many different types of media, such as tapes, CDs, DVDs, or hard disks. Traditionally, tapes were used to back up data. Today, large backups are typically performed using separate hard disks. Smaller backups are performed using CDs or DVDs, which require special burning software described later in this chapter.
What command looks for a Makefile and uses the information within to compile the source code into binary programs using the appropriate compiler program for the local hardware architecture?
make
The dump/restore utility is limited to a maximum of how many different incremental backups?
nine
An RPM package can be converted to a cpio archive using what command?
rpm2cpio
What yum command below can display a list of package group names?
yum grouplist
What command can be used to display the contents of a file that was compressed with the compress utility?
zcat
What option can be added to the dpkg command to remove a specified package from the system, including any configuration files used by the package?
-P
What option can be added to the rpm command in order to query packages?
-q
What command can be used to search for DPM package information?
dpkg-query
RPM packages that require other RPM packages to be installed on a system prior to being installed creates a relationship known as?
package dependency