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software; it can be used to “speak” a text display to a user, but it doesn't interface with Braille displays. GOK (option D) is an onscreen keyboard, not a Braille display tool. Framebuffer drivers (option E) are kernel drivers for managing conventional video cards; they aren't used to drive Braille displays. For more information, see Chapter 6.

      18. C. Some dependencies result from dynamically linking binaries to libraries at compile time, and so they can be overcome by recompiling the software from a source RPM, so option C is correct. Option A describes Debian source packages, not RPM packages. Recompiling a source RPM requires only issuing an appropriate command, although you must also have appropriate compilers and libraries installed. Thus, option B is overly pessimistic. Source tarballs can also be used to compile software for RPM systems, although this results in none of RPM's advantages. Thus, option D is overly restrictive. The RPM format doesn't impose any licensing requirements, contrary to option E. For more information, see Chapter 2.

      19. D. The mv utility can be used to rename files as well as move them from one location to another, so option D is correct. The dd utility (option A) is used to copy files to backups, rm (option B) is used to remove (delete) files, cp (option C) copies files, and ln (option E) creates links. For more information, see Chapter 4.

      20. B. Appending an ampersand (&) to a command causes that command to execute in the background. The program so launched still consumes CPU time, but it won't monopolize the shell you used to launch it. Thus, option B is correct. The start (option A) and background (option D) commands are fictitious. Although bg (option C) does place a job into the background, it doesn't launch a program that way; it places a process that has already been suspended (by pressing Ctrl+Z) into the background. The nice utility (option E) launches a program with modified priority, but a program so launched still monopolizes its shell unless you take additional steps. For more information, see Chapter 2.

      21. A, B. The -Uvh parameter (option A) issues an upgrade command (which installs the program whether or not an earlier version is installed) and creates a series of hash marks to display the command's progress. The -i parameter (option B) installs the program if it's not already installed but causes no progress display. Option C uses a package name, not a complete filename, and so it will fail to install the package file. The -e option (option D) removes a package. Option E's -Vp option verifies the package file but doesn't install it. For more information, see Chapter 2.

      22. B. Option B, fsck, is Linux's filesystem check utility. It's similar in purpose to the DOS and Windows CHKDSK and ScanDisk utilities (similar to options C and D), but these DOS and Windows utilities don't work on Linux filesystems like ext2fs or ReiserFS. Option A, mkfs, creates new filesystems; it doesn't diagnose or fix filesystem problems. Option E, fdisk, is a tool for creating or modifying disk partitions; it doesn't manage the filesystems they contain. For more information, see Chapter 3.

      23. A. A freshly installed MySQL database is unlikely to have a ready-made database of animals, so your first task is to create that database with the CREATE DATABASE command, as shown in option A. (You could call the database something other than animals, of course.) The USE command in option B will be useful only once the database has been created. Once the database is created, you can use CREATE TABLE, as in option C, to create a table; however, you'll need an existing database first, and this command also requires information about the type of data to be stored, which option C doesn't provide. Option D's INSERT INTO command stores data into a table once it's been created, so it's far from the first command you'll use. It also requires additional specification of the data to be stored, so it's incomplete. Option E's UPDATE command modifies existing entries, so you'll use this command only after you've created the database and added at least one animal to it. (Option E is also an incomplete command even then.) For more information, see Chapter 9.

      24. B, D. The correct answers, man and info (options B and D), are two common Linux help packages. Although ? (option C) is a common help command within certain interactive programs, it isn't a help command in bash or other common Linux shells. There is no common command called manual (option A), nor is hint (option E) a valid bash command or common program name. For more information, see Chapter 1.

      25. A, C. Unix systems traditionally store time in UTC (aka Greenwich mean time), and Linux may do so as well. Thus, option A is correct. Most other x86 PC OSs traditionally store time as the local time, however, so Linux also supports this option and option C is also correct. Internet Time (option B) is an alternative to the 24-hour clock in which the day is broken into 1,000 “beats.” Standard PC BIOSs don't support this time format. Likewise, a 12-hour clock isn't terribly useful to computers because it doesn't differentiate a.m. from p.m., making option D incorrect. Although the length of the Martian day is similar to that of Earth (24 hours and 37 minutes), those wanting to colonize Mars will have to wait for PC clocks to support setting time for the Red Planet; option E is incorrect. For more information, see Chapter 7.

      26. D. Typing lsmod (option D) produces a list of the modules that are currently loaded. The insmod (option A) and modprobe (option C) programs both load modules – either a single module or a single module and all those on which it depends, respectively. The depmod command (option B) generates the modules.dep file that contains module dependency information. The modinfo command (option E) displays information, such as its version number and author, on a single module. For more information, see Chapter 3.

      27. B, E. The chgrp and chown commands can both change the group ownership of a file. The chgrp command takes a group name and a filename as parameters, as in option B. The chown command normally changes a file's owner; but if you provide a group name preceded by a dot (.) or a colon (:), as in option E, it changes the group of a file. The chown command as used in option A, will change the primary ownership of the file to the music user, if such a user exists on the system; it won't change the group ownership. There is no standard chgroup command, as in option C. Option D will change the permissions to 0600 (-rw-), which will be a step backward with respect to the goal stated. For more information, see Chapter 4.

      28. E. Hard links to directories are not permitted by most filesystems, so you'll probably have to create a symbolic link, as noted in option E. Links don't rely on a filesystem journal, so option A is incorrect. Contrary to option B, anybody may create a link, not just the original's owner. Option C describes a restriction of hard links, but because this link will probably have to be a symbolic link, this restriction is unimportant and option C is incorrect. Option D describes a more severe restriction than option B, but it's incorrect for the same reasons. For more information, see Chapter 4.

      29. B, E. The colon (:) starts ex mode, from which you can enter commands. In ex mode, r includes a file in an existing one, w writes a file, e loads an entirely new file, and q quits the program. Thus the desired combination is :wq (option B). As a special case, ZZ does the same thing, so option E is also correct. For more information, see Chapter 5.

      30.

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