LPIC-1 Linux Professional Institute Certification Study Guide. Richard Blum

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СКАЧАТЬ (HTTPS), none of which is commonly used for email retrieval. For more information, see Chapter 8.

      13. C. Log files, such as /var/log/messages and sometimes others in /var/log, often contain useful information concerning server errors. The tail program displays the last few lines of a file, so using it to examine log files immediately after a problem occurs can be a useful diagnostic procedure. Option C correctly combines these features. The http://localhost:631 URL of option A accesses the Common Unix Printing System (CUPS) configuration utility, which has nothing to do with SSH. There is no standard diagnose utility (option B) to help diagnose server problems, and there is no standard /dev/ssh file (option D). The sshd program is the SSH server itself, so option E will simply launch the server. For more information, see Chapter 5.

      14. B. The ∼./profile file is one of several bash startup scripts, as stated in option B. It has nothing to do with the ProFTP server (option A) or the tcsh shell (option D). The ProFile file manager mentioned in option C is fictitious. Users' encrypted passwords (option E) are usually stored in /etc/shadow. For more information, see Chapter 9, “Writing Scripts, Configuring Email, and Using Databases.”

      15. E. The at utility was created to run programs at one specified point in the future. Thus, option E will accomplish the stated goal. Options A and C might also work, but neither is the best way to accomplish this goal. Option A will tie up CPU time, and if the program crashes or the system is shut down during the intervening two years, the message will never be displayed. Option C would be more reliable, but it adds unnecessary complexity to your hourly cron job schedule. The cal program displays a text-mode calendar, enabling you to identify the days of a week for a given month; it doesn't schedule future jobs, as option B suggests. A GUI calendar program, as specified in option D, might work, but NTP is the Network Time Protocol, a protocol and like-named program for synchronizing clocks across a network. Thus, NTP isn't the tool for the job, and option D is incorrect. For more information, see Chapter 7.

      16. D. Option D provides the correct command to add 172.24.21.1 as the default gateway. Options A and B both use the fictitious gateway command, which doesn't exist and therefore won't work unless you create a script of this name. Option C uses the correct route command, but there is no gateway option to route; you must use add default gw, as in option D. There is no standard gw command, so option E is incorrect. For more information, see Chapter 8.

      17. B, C. The BRLTTY package is an add-on daemon for handling a Braille display device, and some features for using these devices have been added to the 2.6.26 kernel, so options B and C are correct. Emacspeak (option A) is speech-synthesis 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 СКАЧАТЬ