BLUM. Assessment test
What does the number 703 represent in the following /etc/passwd entry? george:x:703:100:George Brown:/home/george:/bin/tcsh A. The account's human ID (HID) number B. The account's process ID (PID) number C. The account's group ID (GID) number D. The account's globally unique ID (GUID) number E. The account's user ID (UID) number
E. The third field of /etc/passwd entries holds the UID number for the account, so option E is correct. Linux doesn't use any standard identifier called a human ID (HID; option A), although the acronym HID stands for human interface device, a class of USB devices. Accounts don't have PID numbers (option B); those belong to running processes. The account's GID number (option C) is stored in the fourth field of /etc/passwd—100 in this example. Linux accounts don't use globally unique ID (GUID) numbers, so option D is incorrect. For more information, see Chapter 7, "Administering the System."
Which of the following commands will install an RPM package file called theprogram-1.2.3-4.i386.rpm on a computer? (Select two.) A. rpm -Uvh theprogram-1.2.3-4.i386.rpm B. rpm -i theprogram-1.2.3-4.i386.rpm C. rpm -U theprogram D. rpm -e theprogram-1.2.3-4.i386.rpm E. rpm -Vp theprogram-1.2.3-4.i386.rpm
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.
How can you tell whether your system is using inetd or xinetd as a super server? (Select two.) A. Type ps ax | grep inetd, and examine the output for signs of inetd or xinetd. B. Type superserver to see a report on which super server is running. C. Look for the /etc/inetd.conf file or /etc/xinetd.d subdirectory, which are signs of inetd or xinetd, respectively. D. Examine the /etc/inittab file to see which super server is launched by init, which is responsible for this task. E. Type netstat -a | grep inet and examine the output for signs of inetd or xinetd.
A, C. Examining a process listing (obtained from ps) for signs of the super server is the most reliable way to determine which one is actually running, so option A is correct. The presence of the super server's configuration file or files (as in option C) is also a good diagnostic, although some older systems that have been upgraded may have both sets of configuration files. There is no standard superserver utility to report on which one is used, so option B is incorrect. Most distributions launch the super server through a SysV startup script; the /etc/inittab file isn't directly involved in this process, so examining it would be pointless, and option D is incorrect. Although the output of netstat -ap, when typed as root, will include an indication of any instance of inetd or xinetd that's listening for connections, option E omits the critical -p option, which causes the program to display process names. Thus, option E is incorrect. For more information, see Chapter 10, "Securing Your System."
A computer's hardware clock keeps track of the time while the computer is powered off. In what formats may this time be stored on an x86 Linux system? (Select two.) A. Coordinated Universal Time (UTC) B. Internet Time C. Local time D. 12-hour time E. Mars time
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.
Which of the following ports are commonly used to retrieve email from an email server computer? (Select two.) A. 110 B. 119 C. 139 D. 143 E. 443
A, D. Port 110 (option A) is assigned to the Post Office Protocol (POP), and port 143 (option D) is assigned to the Internet Message Access Protocol (IMAP), both of which may be used to retrieve email messages from an email server system. Port 119 (option B) is assigned to the Network News Transfer Protocol (NNTP), port 139 (option C) is assigned to the Server Message Block/Common Internet File System (SMB/CIFS) protocol, and port 443 (option E) is assigned to the Hypertext Transfer Protocol with SSL encryption (HTTPS), none of which is commonly used for email retrieval. For more information, see Chapter 8.
You've just installed MySQL, and you intend to use it to store information about the animals in a zoo, from the anteaters to the zebras. What command are you likely to use first, once you start MySQL? A. CREATE DATABASE animals; B. USE animals; C. CREATE TABLE animals; D. INSERT INTO animals; E. UPDATE animals;
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.
You've configured your computer to use SMTP and IMAP via a tunneled SSH connection to your ISP's email server for improved security. Why might you still want to use GPG encryption for your emails on top of the encryption provided by SSH? A. The SSH tunnel reaches only as far as the first email server; GPG encrypts data on all of the computers all the way to or from your email correspondents. B. SSH encryption is notoriously poor for email, although it's perfectly adequate for login sessions; thus, adding GPG encryption improves security. C. SSH doesn't encrypt the headers of the email messages; GPG encrypts the headers to keep snoopers from learning your correspondents' identities. D. Using GPG guarantees that your email messages won't contain unwanted viruses or worms that might infect your correspondents' computers. E. Configured in this way, SSH will encrypt the email headers and bodies but not any attachments to your email.
A. Option A correctly describes the features of SSH and GPG in this context. Option B is incorrect because SSH should do a fine job of encrypting your email so that it can't be decoded between your system and your ISP's email server. Option C has it backward; email transferred via SSH will be completely encrypted, including both headers and body. GPG doesn't encrypt headers, just message bodies. Option D is incorrect because GPG isn't a virus scanner, just an encryption tool. Option E is incorrect because the SSH tunnel will encrypt everything in the SMTP transfer, including email attachments. For more information, see Chapter 10.
What software can you use to drive a Braille display device? (Select two.) A. Emacspeak B. BRLTTY C. A 2.6.26 or later kernel D. GOK E. A framebuffer driver
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.
Which of the following are journaling filesystems for Linux? (Select three.) A. vfat B. ReiserFS C. Ext2fs Assessment Test xxxix D. Ext3fs E. XFS
B, D, E. ReiserFS (option B) was written from scratch for Linux. The Third Extended Filesystem (ext3fs; option D) is a journaling filesystem based on the older non-journaling Second Extended Filesystem (ext2fs; option C). The Extents Filesystem (XFS; option E) is a journaling filesystem written by SGI for Irix and later ported to Linux. The Virtual File Allocation Table (vfat; option A) is a non-journaling filesystem designed by Microsoft for Windows. For more information, see Chapter 3, "Configuring Hardware."
Which of the following commands displays help on topic, when typed in a Linux shell? (Select two.) A. manual topic B. man topic C. ? topic D. info topic E. hint topic
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.
You want to enable all members of the music group to read the instruments.txt file, which currently has 0640 (-rw-r-----) permissions, ownership by root, and group ownership by root. How might you accomplish this goal? (Select two.) A. Type chown music instruments.txt in the file's directory. B. Type chgrp music instruments.txt in the file's directory. C. Type chgroup music instruments.txt in the file's directory. D. Type chmod 0600 instruments.txt in the file's directory. E. Type chown :music instruments.txt in the file's directory.
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.
Which of the following, when typed in vi's command mode, saves a file and quits the program? (Select two.) A. :rq B. :wq C. :re D. :we E. ZZ
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.
You want to run a lengthy scientific simulation program, called simbigbang, which doesn't require any user interaction; the program operates solely on disk files. If you don't want to tie up the shell from which you run the program, what should you type to run simbigbang in the background? A. start simbigbang B. simbigbang & C. bg simbigbang D. background simbigbang E. nice simbigbang
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.
What tool can diagnose and fix many common Linux filesystem problems? A. mkfs B. fsck C. chkdsk D. scandisk E. fdisk
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 ontain. For more information, see Chapter 3.
Which section in the X server configuration file defines the combination of monitors and video cards that you're using on your Linux system? A. Monitor B. Screen C. Modeline D. Device E. Module
B. The Monitor section defines the monitor options and settings but doesn't combine it with the video card, so option A is incorrect. The Modeline line defines the available video modes in the Monitor section, but it doesn't define video cards, so option C is incorrect. Option D, the Device section, is also incorrect; it defines the video card but doesn't match it with a monitor on the system. Option E is incorrect because the Module section defines which X server modules (or drivers) are loaded but it doesn't match monitors and video cards. Option B, the Screen section, tells the X server about the combination of video cards and monitors that you're using, so it's the correct answer. For more information, see Chapter 6, "Configuring the X Window System, Localization, and Printing."
What does the grep command accomplish? A. It creates a pipeline between two programs. B. It searches files' contents for a pattern. C. It concatenates two or more files. D. It displays the last several lines of a file. E. It locates files on the hard disk.
B. The grep command scans files to find those that contain a specified string or pattern, as described by option B. In the case of text files, grep displays the matching line or lines; for binary files, it reports that the file matches the pattern. The method of creating a pipeline (option A) involves separating two commands with a vertical bar (|). The grep command can be used in a pipeline, but it doesn't create one. The command that concatenates files (option C) is cat, and the command that displays the last several lines of a file (option D) is tail. Several commands, such as find, locate, and whereis locate files (option E), but grep is not among them. For more information, see Chapter 1.
What is the function of the ~/.profile file? A. It's the user configuration file for the ProFTP server. B. It's one of a user's bash startup scripts. C. It's the user configuration file for the ProFile file manager. D. Its presence tells tcsh to ignore file modes. E. It holds the user's encrypted password.
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."
Which of the following are required when configuring a computer to use a static IP address? (Select two.) A. The IP address of the DHCP server B. The hostname of the NBNS server C. The computer's IP address D. The network mask E. The IP address of the NTP server
C, D. The computer's IP address (option C) and network mask (aka subnet mask or netmask; option D) are the most critical components in TCIP/IP network configuration. (Additional information that you may need to provide on many networks includes the IP addresses of one to three DNS servers, the hostname or IP address of a router, and the computer's hostname.) You shouldn't need the IP address of a Dynamic Host Configuration Protocol (DHCP) server (option A)—and if a DHCP server is present, chances are you should be using DHCP rather than static IP address assignment. A NetBIOS Name Service (NBNS) server (option B) converts between names and IP addresses on NetBIOS networks. The hostname of such a computer isn't likely to be a critical configuration element, although you may need to provide this information to Samba for some operations to function correctly when sharing files. A Network Time Protocol (NTP) server (option E) helps you maintain system time on all of your computers, but this isn't required for basic network configuration. For more information, see Chapter 8, "Configuring Basic Networking."
You're experiencing sporadic problems with a Secure Shell (SSH) login server—sometimes users can log in and sometimes they can't. What might you try immediately after a failure to help diagnose this problem? A. On the server computer, type http://localhost:631 into a web browser to access the SSH configuration page and check its error subpage for error messages. B. Type diagnose sshd to run a diagnostic on the SSH server daemon (sshd). C. Type tail /var/log/messages to look for error messages from the server. D. Examine the /dev/ssh device file to look for error messages from the server. E. On the server computer, type sshd to view SSH's diagnostic messages.
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.
Which is true of source RPM packages? A. They consist of three files: an original source tarball, a patch file of changes, and a PGP signature indicating the authenticity of the package. B. They require programming knowledge to rebuild. C. They can sometimes be used to work around dependency problems with a binary package. D. They are necessary to compile software for RPM-based distributions. E. They always contain software that's licensed under terms of the GPL.
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.
What file would you edit to restrict the number of simultaneous logins a user can employ? A. /etc/pam.d/login-limits B. /etc/bashrc C. /etc/security/limits.conf D. /etc/inittab E. /etc/passwd
C. The /etc/security/limits.conf file defines various limits on user resources, including the number of simultaneous logins individual users are permitted. Thus, option C is correct. The /etc/pam.d/login-limits file (option A) is fictitious, although login limits do rely on the pam_limits module to the Pluggable Authentication System (PAM). The /etc/bashrc file (option B) is a global bash startup script file, but it's not normally used to impose login limits. The /etc/inittab file (option D) is a key Linux startup file, but it doesn't have any direct bearing on imposing login limits. The /etc/passwd file (option E) defines many key account features, but login limits are not among these. For more information, see Chapter 10.
Which of the following characters defines the end of an OS or kernel definition in /boot/ grub/grub.cfg? A. ; B. ) C. } D. */ E. None of the above; the definition ends with the title line beginning the next entry.
C. The grub.cfg filename indicates a GRUB 2 configuration file. In such files, each OS or kernel stanza begins with a menuentry line and an open curly brace ({) and ends with a close curly brace (}). Thus, option C is correct. Some configuration files and programming languages use semicolons (;) at the end of most lines, but this isn't true of GRUB 2, so option A is incorrect. Although close parentheses ()) are used to terminate some types of options in some configuration files, including disk identifiers in GRUB 2's configuration file, they aren't used to terminate whole OS or kernel definitions in this file, so option B is incorrect. The string */ terminates comments in C program files but isn't commonly used in GRUB 2 configuration files, so option D is incorrect. Option E would be correct if the question had asked about a GRUB Legacy configuration file (menu.lst or grub.conf), but the question specifies a GRUB 2 configuration file (grub.cfg); the two boot loaders terminate their OS/kernel stanzas differently, so option E is incorrect. For more information, see Chapter 5, "Booting Linux and Editing Files."
A user's home directory includes a file called ~/.forward that consists of one line: |~/ junkme. What is the effect of this configuration? A. The user's incoming mail is forwarded to the junkme user on the same system. B. The user's incoming mail is stored in the ~/junkme file. C. The user's incoming mail is sent through the ~/junkme program file. D. The user's incoming mail is flagged as spam and deleted. E. The user's incoming mail is forwarded to the same user on the junkme computer.
C. The ~/.forward file is a user email forwarding file. The vertical bar character (|) at the start of such a file is a code to send the email through the specified program file, so option C is correct. To do as option A describes, the file would need to read junkme or junkme@ hostname, where hostname is the computer's hostname. To do as option B describes, the leading vertical bar would have to be omitted. It's conceivable that the ~/junkme script does as option D describes, but there's no way of knowing this for certain. To do as option E describes, the file would have to read user@junkme, where user is the username. For more information, see Chapter 9.
How would you configure a computer to use the computer whose IP address is 172.24.21.1 as a gateway for all network traffic that's not otherwise configured? A. gateway default 172.24.21.1 B. gateway 172.24.21.1 C. route gateway 172.24.21.1 D. route add default gw 172.24.21.1 E. gw 172.24.21.1
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.
How does the lpc utility for CUPS differ from its counterpart in BSD LPD and LPRng? A. The lpc utility is unique to CUPS; it doesn't ship with BSD LPD or LPRng. B. CUPS doesn't ship with an lpc command, but BSD LPD and LPRng do. C. CUPS's lpc is much more complex than its counterpart in BSD LPD and LPRng. D. CUPS's lpc is much simpler than its counterpart in BSD LPD and LPRng. E. The lpc utility is identical in all three of these printing systems.
D. The lpc utility is used to start, stop, change the priority of, and otherwise control jobs in a print queue. CUPS ships with an lpc utility, but it's quite rudimentary compared to the lpc utilities of BSD LPD and LPRng. Instead, CUPS relies on its Web-based interface to provide the ability to control print jobs. Thus, option D is correct, and the remaining options must logically all be incorrect. For more information, see Chapter 6.
Which utility should you use by itself to rename the file pumpkin.txt to lantern.txt? A. dd B. rm C. cp D. mv E. ln
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.
You want to know what kernel modules are currently loaded. What command would you type to learn this information? A. insmod B. depmod C. modprobe D. lsmod E. modinfo
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.
You want to create a link to the /usr/local/bin directory in another location. Which of the following statements is true? A. You can do this only if /usr/local/bin is on a journaling filesystem. B. You must own /usr/local/bin to create the link. C. You can create the link only if the link's location is on the same filesystem as the original directory. D. Only the system administrator can do this. E. The link will probably have to be a symbolic link.
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.
You want your computer to remind you to get your car inspected in two years. What is the best way to do this among the specified options? A. Create a program that repeatedly checks the time and, when two years have passed, displays a message to get your car inspected. B. Type cal day month year, where day, month, and year specify the date of the future inspection, to have Linux run a program that you then specify on that date. C. Create a cron job that runs hourly. This job should check the date and, when the correct date comes up, use mail to notify you of the need for a car inspection. D. Use the NTP GUI calendar program to create an alarm for the specified date. The program will then display the message you enter at the specified date and time. E. Type at date, where date is a date specification. You can then specify a command, such as mail with appropriate options, to notify you of the need to get your car inspected.
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.
What does the following command accomplish? $ wc report.txt | tee wc A. It launches the wc editor on both the report.txt and wc.txt files; each file opens in its own window. B. It displays a count of the windows in which the report.txt file is displayed and shows that information in a new window called wc. C. It creates a count of newlines, words, and bytes in the report.txt file and then displays a count of these statistics about the report it just generated. D. It cleans up any memory leaks associated with the tee program's use of the report .txt file. E. It displays a count of newlines, words, and bytes in the report.txt file and copies that output to the wc file.
E. The wc command displays a count of newlines, words, and bytes in the specified file (report.txt). Piping this data through tee causes a copy of the output to be stored in the new file (wc in this example—you shouldn't run this command in the same directory as the wc executable file!). Thus, option E is correct. Contrary to option A, wc is not an editor, and the remaining syntax wouldn't cause two files to open in separate windows even if wc were an editor. Contrary to option B, wc doesn't count windows or open a new window. Option C describes the effect of wc report | wc—that is, it overlooks the tee command. Contrary to option D, wc has nothing to do with cleaning up memory leaks, and tee doesn't directly use the report.txt file. For more information, see Chapter 1, "Exploring Linux Command-Line Tools."