ccpq/data/tmp/lpic1_pratice_book_solutions.csv

1	1. D. The udevadm command is used to work with the udev interface of the kernel, and the
2	monitor subcommand displays kernel uevents and other udev events in real time.
3	2. B. Current IRQ assignments are contained in the file /proc/interrupts. Therefore,
4	viewing the contents of the file with a command such as cat will work. There is no “view”
5	command, making option A incorrect. Likewise, there is no /dev/irq file, making options
6	C and D incorrect.
7	3. D. Configuration files for udev are found in /etc/udev, which makes option D correct.
8	The other options do not exist.
9	4. A. The modprobe command loads the module and its dependencies, if applicable. The
10	lsmod command is used to list currently loaded modules, making option B incorrect. The
11	insmod command will load a given module but not its dependencies. Option D, rmmod, is
12	used to remove a module from memory.
13	5. B. The lsusb command is used to obtain a basic list of USB devices on a system. The other
14	commands are not valid. In the case of option D, the ls command is valid, but there is no
15	--usb option.
16	6. B. The info command for udevadm enables querying for additional information about a
17	hotplug device managed with udev.
18	7. D. The dmesg command displays the contents of the kernel ring buffer. On many Linux
19	distributions, this log is also saved to /var/log/dmesg. The other options shown for this
20	question are not valid commands.
21	8. C. Runlevel 1, sometimes displayed as runlevel s or S, is single-user mode in which many
22	services are not started. Runlevels 5 and 6 are used for other purposes, and runlevel SU is
23	not a valid option.
24	9. D. Scripts are stored in /etc/init.d on a system using SysV init. You may sometimes
25	find these linked from /etc/rc.d/init.d as well. The other options are not valid for this
26	question.
27	10. A. The init command can be used to access different runlevels. Runlevel 6 is used for
28	rebooting the system. Option B will shut down the system entirely, not reboot it. Option C
29	will place the system into single-user mode. Option D is not a valid option.
30	11. C. The telinit command can be used to refresh the system after changes have been made
31	to /etc/inittab. Notably, option B will reboot the system but that was not an option in
32	the question. Options A and D are not valid commands.
33	12. D. The runlevel command displays the current runlevel for a system. Option B is not a
34	valid option to the init command, and adding sudo in front of the init command makes
35	no difference. Option A is not a valid command.13. C. Unit configuration files are stored in /lib/systemd/system. The other directory
36	options for this question are not relevant or do not exist by default.
37	14. B. The systemctl command is used to work with services and targets. The list-units
38	command is used to list targets. The other commands are not used for this purpose or do
39	not exist with the required option.
40	15. C. The -nn option displays both numbers and device names, making option C correct. The
41	-n option (option B) displays only numbers. The other two options do not exist.
42	16. D. The lsmod command is used to list currently loaded kernel modules, making option D
43	correct for this question. The insmod command (option A) is used to load modules. Option
44	C is a valid command but not a valid option for that command, and option B does not
45	exist.
46	17. C. The --show-depends option shows the modules that depend on the specified module.
47	The other options do not exist.
48	18. B. The wall command is used to send a message to all users, thereby making option B
49	correct. The cat command is used as a means to concatenate or view files, and tee is used
50	to send output to standard output and a file. Finally, ssh is the secure shell client command
51	and is not used for the purpose specified.
52	19. B. Checking to ensure that the disk is detected in the basic input/output system (BIOS)
53	is a good first step in troubleshooting. Option A, unplugging the disk, won’t help it to
54	be detected. Restarting the web server won’t help detect the disk, and the disk-detect
55	command does not exist.
56	20. D. The /sys/bus/usb/devices directory contains information about USB devices. The
57	other directories are not valid for this purpose.
58	21. D. The file /var/log/dmesg will typically contain historical messages from the current
59	booting of the system. On some distributions of Linux, this information is also in
60	/var/log/boot.log.
61	22. C. Out of the options given, the systemctl status command and option is the most
62	appropriate. The telinit and sysctl commands are not used for this purpose. Likewise,
63	the --ls option is not valid for systemctl.
64	23. B. The isolate option is used to move the system into the target specified, making option
65	B the correct one. The other options do not exist.
66	24. A. The initctl reload command causes Upstart to reread its configuration files.
67	25. B. The --list option will show all services on a system along with their status for each
68	runlevel.
69	26. C. USB devices are generally considered to be hotplug devices. Hotplug devices describe
70	those devices that can be inserted and removed while the system is “hot,” or powered on,
71	whereas coldplug devices are those that must be inserted and removed when the system is
72	powered off.27. B. The umount command is used to unmount drives within a running system. The other
73	commands do not exist.
74	28. D. Of the options presented, running dmesg is a common way to determine the location to
75	which the kernel has assigned the drive. Rebooting the system is not a good option, though
76	it would work. There is no such thing as /var/log/usb.log, and the location of the drive
77	may change regardless of port, depending on how the drive may be detected in the system.
78	29. B. From these options, only B will shut down the system immediately. Option A will cancel
79	a shutdown.
80	30. C. The ExecStart option indicates the command to be executed on startup of a systemd
81	service.
82	31. D. The systemctl get-default command will show the default target. The other
83	commands and options are not valid.
84	32. A. The enable option configures the service to start on boot. The start option, D, is used
85	to start a service immediately. The other options are not valid for this command.
86	33. C. The /proc filesystem contains information about currently running processes and
87	additional information about the kernel and current boot of the system.
88	34. C. The -t option to lsusb will print output in a tree-like format so that you can see which
89	devices are connected to which bus. The other arguments to lsusb are not valid, and the
90	usblist command is not real.
91	35. D. If a working device does not appear in lsmod, it typically means that the kernel has a
92	driver already loaded by virtue of being compiled into the kernel itself rather than loaded
93	through a module. The use of systemd (option A) or initramfs (option B) has no effect.
94	36. C. The -w option causes the module to wait until it’s no longer needed prior to unloading.
95	The -f option forces immediate removal and should be used with caution. The other
96	options are not valid for rmmod.
97	37. B. The tune2fs command can be used for this purpose but should be used with care
98	because it can result in data corruption.
99	38. C. Rules related to udev are stored in /etc/udev/rules.d. The /etc/udev hierarchy
100	contains the udev.conf configuration file along with other components related to the
101	configuration of udev.
102	39. B. The -k option shows the kernel driver associated with a given PCI device and can be
103	helpful when planning a new kernel compile. The -t option displays information in a tree-
104	like structure, and -n uses numbers instead of device names. There is no -a option.
105	40. B. The /etc/modprobe.d directory is used for storing configuration information related
106	to modules such as that used for blacklisting purposes but also for other configuration
107	information, such as udev and module options.41. B. The dracut command is used to create the initial RAM disk for newer systems and has
108	replaced the legacy mkinitrd command used for the same purpose.
109	42. D. The file /proc/kallsyms provides a way to view the currently loaded kernel symbols.
110	This can be helpful for resolving module dependencies. Note that on legacy systems, this
111	file might be called /proc/ksyms.
112	43. A. The systool utility can be used to show currently loaded options for a given module.
113	The modinfo -r command is not valid, and though modinfo shows information about a
114	module, it does not include core size and other settings. The lsmod command cannot be
115	used for this purpose, and there is no infmod command.
116	44. B. The /proc/sys/kernel hierarchy contains vital configuration information about a
117	kernel. These settings can be changed on a running system.
118	45. B. The /etc/systemd/system directory is where it is recommended to store unit files for
119	systemd. The other locations are not valid.
120	46. C. The systemctl command will be used for this purpose with the daemon-reload
121	subcommand. The reboot option would work to reload the systemd configuration but is
122	not correct because it requires the entire server to reboot, which is not what was asked in
123	this question.
124	47. B. The /etc/inittab file contains the various runlevels and what to run at the given
125	runlevel. For example, runlevel 1 is single-user, runlevel 6 is reboot, and so on. The other
126	files listed do not exist.
127	48. B. The SYSLINUX boot loader is used for FAT filesystems to create rescue disks and to
128	assist with installation of Linux in general. SYSLINUX also describes an overall project
129	containing other specialty boot loaders. The other options listed for this question are not
130	valid boot loaders, though.
131	49. C. initrd is used for an initial root filesystem for early drivers. initrd is configured to
132	load within the GRUB configuration file for a given operating system.
133	50. B. The fsck command is used to diagnose and repair hard drive problems in Linux. The
134	defrag command is not available in Linux.
135	51. D. The telinit command can be used for this purpose, and passing 1 as the argument
136	will switch the system into single-user mode. The other commands shown are not valid.
137	52. D. The -n option changes the boot order for the next boot only and boots from the
138	specified partition. The -b along with -B modifies and then deletes the option. The -o
139	option sets the boot order. The -c option creates a boot number.
140	53. A. ISOLINUX provides a means by which CD-ROMS formatted as ISO 9660 can be
141	booted. It’s very common to have live CDs or rescue/recovery CDs that use ISOLINUX for
142	boot. The other boot loaders are not valid for this purpose or don’t exist.54. A. The /usr/lib/systemd hierarchy contains files related to systemd configuration. The
143	user directory within the hierarchy is used for user unit files, and the system files are stored
144	in /usr/lib/systemd/system.
145	55. B. Due to the decidedly insecure decisions made with the design of Microsoft’s UEFI, a
146	shim is often needed to enable Linux to boot on a system with UEFI. The shim.efi file can
147	be used as an initial boot loader for this purpose.
148	56. D. Scripts for starting and stopping services are located in /etc/init.d on a SysV
149	init-based system. The other directories listed within this question are not valid.
150	57. C. The systemd-delta command is used to determine overridden configuration files. Of
151	the other commands, diff is valid but not for this purpose. The systemctl command is
152	also valid, but again, not for the purpose described.
153	58. B. The chkconfig --list command displays all services that will be executed on boot
154	along with the setting for each service for each runlevel. Of the other commands, the
155	init command is valid but does not have a --bootlist option. The other commands are
156	invalid.
157	59. B. The bcfg command within the UEFI shell is used to configure boot loaders on a UEFI-
158	based system. The command can accept various parameters to configure how the boot
159	loader and kernel will load on boot. Of the other commands shown, grub-install is valid
160	but not within the UEFI shell.
161	60. D. The pxelinux.0 file must exist within /tftpboot on the TFTP server in order for
162	a system to use PXELINUX for booting. The other files are not valid or necessary for
163	PXELINUX.
164	61. D. The update-rc.d utility can be used to manage SysV init scripts on Debian or Ubuntu
165	and other distributions. When using update-rc.d, you supply the script name and the
166	utility will take care of creating symlinks to the appropriate runlevels.
167	62. B. The e key, when pressed at the right time during boot, will send you into the GRUB
168	shell, where you can change parameters related to boot, such as the kernel options and
169	other related parameters.
170	63. D. The isolate subcommand followed by the desired target is used to switch between
171	runlevels with a systemd-based system. The other subcommands shown are not valid for
172	systemctl.
173	64. C. The runlevel defined as initdefault is the default runlevel for the system. The other
174	options shown do not exist.
175	65. B. The initramfs system is used instead of initrd to create the filesystem-based loading
176	process for key drivers that are needed for boot.
177	66. A. The systemctl command will be used for this purpose, and the set-default
178	subcommand is necessary to affect the desired behavior. The target file is simply called
179	multi-user.target.67. C. The shim.efi boot loader loads another boot loader, which is grubx64.efi by default.
180	The other options are not valid filenames for the purpose described.
181	68. D. The /etc/rc.d hierarchy contains symbolic links to files found within /etc/init.d.
182	These symlinks are then used for executing the scripts at the appropriate runlevel. For
183	example, on boot the system will execute the scripts found in the runlevel directory for each
184	runlevel executed at boot time.
185	69. A. The default.target is the default target unit that is activated by systemd on boot.
186	The default target then starts other services based on the dependencies.
187	70. B. LUNs that contain the characters fc are found through Fibre Channel. Therein lies the
188	difference between options B and C, where option C contains the letters scsi, which would
189	usually represent a local disk. The other options are not valid.
190	71. B. NVMe-capable drives are named /dev/nvme*. No special drivers are needed other than
191	those found in the native kernel on a modern system. The other options do not exist as
192	paths by default.
193	72. D. The /proc/mdstat file contains information on RAID arrays, including RAID
194	personalities found on the system, the devices that comprise the array, and other pertinent
195	information. The other files shown are not valid.
196	73. B. The /sys/class/fc_host directory contains other directories based on the Fibre
197	Channel connections available. Within those host directories will be found the WWN in a
198	file called port_name. The other directory hierarchies are not valid.
199	74. C. The /dev/mapper directory contains information about multipath devices such as
200	logical volumes. The other directories are not valid.
201	75. C. The lspci command will be used for this purpose. NVMe devices are listed with the
202	name nVME or NVMe; therefore, adding -i to grep will make the search case insensitive.
203	You’d use this in order to ensure that the devices are detected. The other commands are
204	not valid, with the exception of the lspci command, but you cannot grep for scsi in this
205	scenario.
206	76. D. Tape devices are found within /dev/st*, making st0 the first device.
207	77. C. The /etc/issue file is used to provide a message to users, such as a login banner, prior
208	to local login. The other files shown are not valid for the purpose described.
209	78. C. The contents of the file motd, an abbreviation for Message of the Day, are displayed
210	when a user logs in successfully. Among the other options, the contents of /etc/issue are
211	displayed prior to local login. The other filenames are not valid for this purpose.
212	79. B. The /etc/issue.net file is used to provide a message for remote logins such as telnet.
213	The other files listed are not valid for the purpose described.
214	80. D. The poweroff target of systemd, accessed using the systemctl command, is used for
215	halting the system and then attempting to remove power on compatible systems. The halt
216	target stops the system but does not attempt to remove power, whereas reboot simply
217	restarts the system. There is no stop target.81. A. The -r option is needed to specify reboot, and the format for counting time from now is
218	prefaced with a plus sign (+), making option A correct. Of the other commands, specifying
219	+15 without the -r option simply shuts down the computer in 15 minutes, and specifying
220	the time as 00:15, as in option D, will shut down the computer at 12:15 a.m.
221	82. A. The service command is used to work with services, such as starting and stopping
222	them. On newer systems, the systemctl command has replaced the service command.
223	83. A. The journalctl command with the -b option displays boot messages.
224	84. A. The -h option halts the system, including shutting down acpid-related hardware.
225	85. C. The number 9 corresponds to SIGKILL and can be passed to the kill command to
226	issue that signal. The number 1 is SIGHUP. Others can be found within the manual for the
227	kill command.
228	86. C. The /etc/init.d directory contains the startup and shutdown scripts for services on a
229	Debian system that is not running systemd.
230	87. A. Among the options, examining the boot messages would be a first logical step and
231	would prevent having to reboot the system. Rebooting may be a next step in order to
232	examine the status of the peripheral within the BIOS.
233	88. C. The -n option prevents the banner from displaying when using wall. The other options
234	shown are not used with the wall command.
235	1. C. SATA disks are addressed as /dev/sdX, just like a Small Computer System Interface
236	(SCSI ) disk. /dev/hdX is a traditional ATA disk. The other options do not exist.
237	2. C. The keyword single, given on the Linux kernel command line, will boot the system
238	into single-user mode. The other options are not valid.
239	3. A. The Shift key, if pressed when control has first been handed to GRUB, will cause the
240	GRUB menu to be displayed.
241	4. B. The root=/dev/sda2 option will cause the given kernel to load /dev/sda2 for its root
242	partition. The rootpartition option is not valid, and the format of the root={hd0,3} is
243	not valid in this context.
244	5. C. You begin an editing session with an e when the boot option is highlighted. You can
245	then make changes and, when done, press b to boot the system.6. D. The root partition is mounted after device initialization. System services, including
246	multi-user mode, start after the root partition is mounted. The other two options, A and C,
247	take place prior to the kernel-initializing device drivers. This process is essentially the same
248	for virtual machines as it is for physical machines.
249	7. D. The ESP is typically mounted at /boot/efi.
250	8. D. The partition containing /var should be the largest for a mail server because mail
251	spools are stored within this hierarchy. The /etc/ hierarchy is usually small, as is /usr/
252	bin. The /mail directory does not exist by default.
253	9. C. The rootnoverify option is used to specify a non-Linux kernel, one that GRUB should
254	not attempt to load. The initrd option is used for specifying the initial RAM disk, making
255	option A incorrect. The remaining options, B and D, are not valid options for GRUB.
256	10. A. The update-grub command sends its output to STDOUT. Therefore, you must redirect
257	using > and send that output to the correct file. The other options are not valid for this
258	purpose. Options C and D are not valid commands, and option B contains invalid options
259	as well as an invalid location for the destination file.
260	11. B. MBR-based disks can be partitioned with up to four primary partitions, one of which
261	can be further partitioned or extended into logical partitions.
262	12. D. The ldconfig command updates the current shared library cache and list. ldconfig
263	reads /etc/ld.so.conf and incorporates any changes found within it. The other
264	commands listed as options for this question do not exist.
265	13. B. The upgrade option for apt-get will upgrade the system to the latest version of
266	software for packages already installed. The apt-update command does not exist, nor
267	does the -U option to dpkg. The apt-cache command is used to work with the package
268	cache.
269	14. C. The yum install command will install a given package. The update option will
270	update a package. The other options listed do not exist.
271	15. C. Root’s home directory is /root on a Linux system. While the /home directory does
272	exist, there is no root or su user within that hierarchy by default. The / directory is the root
273	of the filesystem but not the root’s home directory.
274	16. A. rpm2cpio sends its output to STDOUT by default, and therefore that output needs to be
275	redirected to a file in most cases.
276	17. B. The /usr hierarchy contains many of the programs that run on a Linux system. Other
277	notable directories for programs are /bin and /sbin.
278	18. B. GRUB begins its count at 0 and in this scenario there are two operating systems.
279	Therefore, because Linux is first in the configuration file its number would be 0, which is
280	then sent to the default= option.19. A. The /etc/default/grub file can be used for this purpose. You may also edit /boot/
281	grub/grub.cfg, but this was not an option given for this question.
282	20. B. The deplist option displays the dependencies for the given package. The list option
283	displays information about a specific package while the other two options are not valid.
284	21. A. The -ivh options will install a file using rpm, displaying both verbose output and hash
285	marks for progress. The other options presented do not exist or do not accomplish the
286	specified task.
287	22. B. The export command is used to set environment variables in BASH. The other
288	commands are not valid for this purpose.
289	23. D. The yumdownloader utility will download an RPM package but not install it. The
290	yumdownloader utility is part of the yum-utils package. The other options listed for this
291	question do not exist.
292	24. A. The apt-cache command is used to work with the package cache and the search
293	option is used to search the cache for the supplied argument, in this case zsh. The apt-get
294	command is used to work with packages themselves, and the apt search command does
295	not exist.
296	25. C. The GRUB_DEFAULT option, when in the /etc/default/grub file, is used to configure
297	the operating system that will boot by default. The other options do not exist in this
298	context.
299	26. A. The ro option, which is the default for GRUB, will initially mount the root partition as
300	read-only and then remount as read-write.
301	27. D. Configuration files related to the repositories for yum are located in /etc/yum.repos.d.
302	Of the other options, /etc/yum.conf is a file and not a directory, and the other directories
303	do not exist.
304	28. A. The -V or --verify option will check the files in a given package against versions
305	(or checksums) in the package database. If no files have been altered, then no output is
306	produced. Note that output may be produced for files that are changed during installation
307	or for other reasons. Note also the use of an uppercase V for this option as opposed to the
308	lowercase v for verbose.
309	29. C. The -o option can be used to specify a destination file to which output will be sent
310	instead of STDOUT. The other options listed in this question do not exist.
311	30. A. The menu.lst and grub.conf files are used in GRUB Legacy, that is, prior to GRUB 2.
312	This therefore makes option B incorrect.
313	31. D. The ldd command will list the libraries on which the command’s argument depends.
314	32. B. Swap space is used when there is insufficient RAM memory on a system.
315	33. B. The /etc/lib directory is not typically associated with library files and does not usually
316	exist on a Linux system unless manually created. The other options either contain system
317	libraries or can be used for that purpose.34. C. The apt-get update command will cause the package cache to be updated by
318	retrieving the latest package list from the package sources. There is no cache-update or
319	update option to apt-cache. The upgrade option is used to update the system’s packages
320	and not the cache.
321	35. C. The sources.list file located in /etc/apt contains the list of repositories for Debian
322	packages. The other file locations do not exist by default.
323	36. A. The /boot partition will typically be much less than 500MB but should not be
324	undersized. The used space within /boot will increase as more kernels are added, such as
325	during an upgrade process. Therefore, even though the recommended size is up to 500MB,
326	experience proves that a larger partition is helpful, possibly 1GB to 2GB.
327	37. B. The pvcreate command initializes a physical partition for future use as a logical
328	volume with LVM.
329	38. D. The grub-install command is used to install GRUB onto a disk and the second SATA
330	disk would be /dev/sdb, making option D correct.
331	39. A. The dpkg-reconfigure program will cause an already installed package to be
332	reconfigured or changed. The -r option for dpkg removes a package, making option B
333	incorrect. There is no reconf option for dpkg or reinstall option for apt-get.
334	40. C. The lvcreate command is used to create logical volumes with LVM. The pvcreate
335	command initializes physical volumes prior to creating logical volumes. The commands in
336	the other two options for this question do not exist.
337	41. A. Physical volumes are initialized first, followed by volume group creation, and then
338	logical volume creation.
339	42. D. aptitude provides the terminal-based interface rather than the standard command-line
340	interface of the other tools listed in this question.
341	43. D. The search option performs a search of various fields such as the package name and
342	description.
343	44. B. The rpm -qa kernel command will show the kernel version. You can also use
344	uname -r for the same purpose.
345	45. C. The GRUB_DEFAULT option in /etc/default/grub will set the operating system to boot
346	by default.
347	46. A. The exclude option can be used to exclude certain packages. The argument accepts
348	wildcards, and therefore excluding all kernel* updates will create the desired behavior.
349	47. B. The grub-mkconfig command should be run after making a change to the /etc/
350	default/grub file so that a new configuration file can be created with the changed
351	option(s).
352	48. B. The -s option to dpkg searches for the given package and provides information about
353	its current status on the system. The apt-cache command is not used for this purpose, and
354	the -i option for dpkg installs a package. The apt-info command does not exist.49. C. The lvmdiskscan command looks for physical volumes that have been initialized for
355	use with LVM.
356	50. B. The --resolve option will download the dependencies of the package being
357	downloaded. The other options shown within this question are not valid for the
358	yumdownloader command.
359	51. A. The -i option to dpkg will install a previously downloaded package. The other
360	commands don’t exist, and the -U option for dpkg does not exist.
361	52. D. GRUB Legacy begins counting at 0 and separates disk letter and partition with a
362	comma, making 0,0 the first partition on the first disk. Options A and C are not the first
363	disk on the system, and option B contains a nonexistent partition.
364	53. A. ESP uses the legacy FAT filesystem type for its underlying format. There is a
365	specification for how the ESP partition must be created on top of the FAT format for boot
366	loaders and kernel images. Note that the partition is typically FAT32 but can be FAT16 if
367	only Linux systems will reside on the drive.
368	54. A. The --install option is used followed by the partition to which extlinux will be
369	installed for boot.
370	55. C. The format for the mount command is [partition] [target], making option C
371	correct. The other options are not valid because the arguments are in the wrong order.
372	56. B. The master boot record (MBR) is the first sector on a disk and contains information
373	about the structure of the disk. If the MBR becomes corrupt, all data on the disk may be
374	lost. The other options shown for this question are not valid.
375	57. D. The --boot-directory option enables you to specify an alternative location for GRUB
376	images rather than the default /boot. The other options shown for this question are not
377	valid.
378	58. D. The /etc/mtab file lists the currently mounted filesystems. The /etc/fstab file
379	lists overall filesystems for the computer but does not distinguish between mounted or
380	unmounted filesystems. The other options listed for this question do not exist.
381	59. B. The swapon command enables swap space, making it available for use as virtual
382	memory. The mkswap command formats the space. The other two commands are not valid.
383	60. C. The pvdisplay command shows information about a given physical volume. You can
384	use pvdisplay to view the device on which the PV is built along with the extent size of the
385	PV. The other commands shown are not valid.
386	61. B. The lvcreate command is used to create a logical volume from previously created
387	physical devices and volume groups. Using lvcreate is the final of three steps in the
388	process for using LVM prior to actually using the logical volume.62. A. The vgscan command looks for both physical volumes and volume groups related to
389	an LVM configuration. The vgscan command is run at system startup but can also be run
390	manually. The other commands are not valid.
391	63. C. The pvscan command displays a list of physical volumes on a given server. The PVs
392	displayed are those that have been initialized with pvcreate for use with LVM.
393	64. A. The -a or --activate option sets whether or not the logical volume can be used. There
394	is no -b or -c option, and the -d option is used for debugging.
395	65. C. The script is using a relative path to look for srv/vhosts rather than /srv/vhosts with
396	an absolute path back to the root directory of the system.
397	66. B. Application containers share kernel and other resources with the underlying OS and use
398	a container daemon to communicate between the host OS and the application container.
399	Virtual machines have their own kernel and are self-contained machines running on top of
400	a host OS or host kernel. Linux containers also provide a containerized virtual machine–
401	like experience but are distinct from application containers.
402	67. D. The /etc/ld.so.conf directory is used in addition to /lib and /usr/lib to configure
403	library locations. The other paths and files shown do not exist.
404	68. A. Among these options, compute resources, such as adding more CPUs, would be the most
405	likely option. Adding RAM might also be warranted, but that was not one of the available
406	options for this question. There is no indication in the question that the network is slow,
407	and there is no indication that adding disk space or block storage (which are essentially the
408	same thing in this context) will help.
409	69. A. GRUB 2 uses grub.cfg whereas GRUB uses menu.lst and grub.conf, making option
410	A the correct choice.
411	70. B. The MAC address will be unique for each virtual machine deployed using the image.
412	Guest drivers would usually not be unique to an individual virtual machine but might be
413	unique on a per-template or per-image basis. System directories are not unique per virtual
414	machine, and there is no such thing as pilot homing in this context.
415	71. B. The cloud-init program is available on Ubuntu and other distributions and can be
416	used to deploy images to popular cloud providers.
417	72. C. The yum package manager configuration file is /etc/yum.conf. The other files listed do
418	not exist.
419	73. B. The -L option to dpkg lists the files included with a given package. The -f option to
420	dpkg shows a field from a package entry, and the other options do not exist.
421	74. A. The public key is deployed to the authorized_keys file on each image, and the private
422	key is used from the host to connect to each virtual machine. There is no reason to deploy
423	the private key to the virtual machine in order to make a connection to it.75. A. The /boot/efi partition needs to exist for the EFI partition and is typically sized
424	100MB to 250MB, though that size can vary.
425	76. A. The install option, or simply in, will install a package on a system that uses zypper
426	for package management. Among the other options listed, the ref option refreshes the
427	repository. The other options are not valid with zypper.
428	77. D. A system running Fedora 22 will use the dnf package manager by default. The yum
429	package manager is used on CentOS and Red Hat, and apt and dpkg are used on Debian.
430	78. A. The repoquery command with the -l option is used for this purpose. The dpkg -L
431	command is appropriate for this purpose on Debian systems. The other commands do not
432	exist.
433	79. C. Home directories for normal users are in /home and the home directory for root is at
434	/root, making option C correct.
435	80. A. The /etc/machine-id file contains the unique identifier for a given machine.
436	81. A. The -n option tells ldconfig to process only the directories given on the command line.
437	The -i option ignores the auxiliary cache file. The -v option is verbose, and -r changes the
438	root directory from which to begin processing.
439	82. C. The stats option shows total package names along with other information about the
440	package cache. The other options are not valid for use with apt-cache.
441	83. D. The --efi-directory option is used to specify the location of the EFI partition,
442	typically /boot/efi.
443	84. A. The /etc/fstab file contains a list of partitions for the system. The /etc/mtab file
444	contains currently mounted partitions. The other files do not exist.
445	85. B. The options qlp list the files in an rpm package. The other options are not valid for the
446	purpose described in the question.
447	86. B. Among the commands and options shown, the info option to yum is used for this
448	purpose. The dpkg and apt package managers are used on Debian systems and thus would
449	not be appropriate for a CentOS system.
450	87. A. The presence of the string vmx in the flags section indicates that an Intel processor is
451	capable of virtualization. This extension is called svm on an AMD architecture.
452	88. A. The lvm.conf file is a primary configuration file for LVM. Within lvm.conf, typically
453	found in /etc/ or /etc/lvm/, you can set things like filters for devices to include or
454	exclude from the vgscan process. The other files shown are not valid.
455	89. C. The --show option displays information about the swap spaces on the computer,
456	including how much swap is currently being used. The -a option activates all swap spaces.
457	There is no --list option, and -h displays help.
458	1. D. The set command can be used for a variety of purposes to change how the shell
459	environment works. One such option is –C, which prevents output redirection such as that
460	done with > from overwriting a file if the file already exists.
461	2. B. The env command will print the current environment variables from Bash. The
462	printenv command will perform the same operation. The other commands listed in this
463	question do not exist.
464	3. C. The man command displays documentation for the command given as the argument.
465	The other options listed for this question do not exist.
466	4. D. The uname command is used to print system information, and the -a option prints all
467	information available to uname.
468	5. A. The g option, also known as global or greedy, will apply the matched operation to the
469	entire line rather than just the first instance of the match. The other options apply as they
470	would for a Perl-Compatible Regular Expression. Note also the tr command that provides
471	some of the same functionality as sed.
472	6. C. The -l option provides the number of lines given as input. For example, wc -l /etc/
473	passwd would print the number of lines in the /etc/passwd file. The other options given in
474	this question are not valid for the wc command.
475	7. C. Both head and tail print 10 lines of output by default.
476	8. B. The -rf options to rm will recursively remove the contents of a directory, including
477	other directories. The -f option alone will not work in this case because of the additional
478	directories. The other options given for rmdir do not exist.
479	9. D. The -type option causes find to limit its search to directories only, whereas the
480	-name option limits the names of returned elements. Note the use of the wildcard due to
481	the phrasing of the question. Also note the use of ./ to denote beginning the search in the
482	current directory.
483	10. A. The cat command will display the contents of file /etc/passwd and then pipe that
484	output to the awk command. The awk command then parses its input, splitting along the
485	specified separator for /etc/passwd, which is a colon (:). The output is then printed and
486	piped to the sort command. The sort command in option B will not work because the
487	cut command requires an argument. Likewise, the echo command in option C will only
488	echo /etc/passwd to STDOUT.
489	11. C. The -l option for ls produces long or listed output and -t sorts by time stamp. The -r
490	option reverses the order, and -a is needed to include hidden (dot) files, making option C
491	correct.12. A. The time stamp of the file will change when touch is run on a file that already exists.
492	13. D. The -i option will cause both cp and mv to be interactive, that is, prompt before
493	overwriting. The -f option will force the command to run, whereas -r is recursive.
494	14. C. The tee command will send output both to STDOUT and to the specified file, making
495	option C correct. Option A will redirect output to the correct file but not to STDOUT
496	simultaneously. The other options will not work for this question.
497	15. A. The -p option will cause mkdir to create additional levels of directories without error.
498	Running mkdir without options will not work in this case. The -r and -f options to mkdir
499	do not exist.
500	16. B. The -R option will copy directories recursively. Note that if the -i option is not enabled,
501	the recursive copy will overwrite files in the destination. The -v option adds verbosity but
502	does not cause any recursion, and the -Z option does not exist.
503	17. C. The file command can be used to determine which type of file is being used. This can
504	be particularly helpful for files without extensions where you are unsure if you should view
505	the contents of the file. Option A, grep, is used to look within files but would not be helpful
506	in this case. The telnet and export commands are not used for this purpose.
507	18. C. The dd command is used to create disk images, among other things. In this case, the
508	input file is /dev/sda1 and the output file is output.img. It’s also common to add the
509	blocksize option by using the bs argument, such as bs=1M.
510	19. B. The cut command uses Tab as its default delimiter. This can be changed with the -d
511	option.
512	20. A. The -z option will unzip the file, -x will extract from the tar archive, and -f is used to
513	indicate the file on which to perform the aforementioned operations. It’s typical to add -v
514	for verbose output as well.
515	21. D. The fg command will bring a command to the foreground if it has been backgrounded
516	with either & or with the bg command.
517	22. B. While the ps auwx command combined with grep will provide information on the
518	running Apache instances, it will provide much more information than is required or useful
519	for this problem. The pgrep command provides only the process IDs and therefore meets
520	the criteria presented in the question.
521	23. D. The top command is used to continuously monitor things like CPU and memory
522	usage, and the -p option monitors a single process. By using the runquotes with the pidof
523	command, the process ID is provided as input to the -p option.
524	24. D. The free command displays overall memory usage for both RAM and swap and can be
525	used to determine when additional memory might be needed.
526	25. A. You need to write the changes to the file; therefore you’ll need :w. The addition of q will
527	also quit. Note that you could use ZZ to write and quit as well. The dd command deletes a
528	line, and x deletes a single character.26. D. The -n option changes the number of lines of output for both head and tail to the
529	number specified. The other options listed in this question are not valid for head, and the
530	-f option follows a file with tail as the file grows.
531	27. A. The uptime command shows basic information such as that described along with the
532	number of users logged into the system and the current time. The bash command is a shell
533	environment, and the ls command will not display the required information.
534	28. D. The screen command starts a new terminal that can be disconnected and reconnected
535	as needed. Processes running from within the screen session do not know that they are
536	running in a screen session and therefore meet the criteria needed to satisfy this question.
537	The fg and bg commands will not meet the criteria, and the kill command will stop a
538	process.
539	29. C. The -9 option invokes SIGKILL, which will force the process to end. The 15 signal is
540	the default, and the -f and -stop options do not exist.
541	30. C. Within Bash, the number 1 represents STDOUT and 2 represents STDERR. Redirecting
542	both means combining them in the manner shown in option C.
543	31. B. The nice command, when run without arguments, will output the priority for the
544	currently logged-in user, which is normally 0. The renice command can be used to change
545	the priority of running processes. The other two commands shown as options for this
546	question do not exist.
547	32. D. Within a regular expression, * represents 0 or more characters. In this case, it doesn’t
548	matter whether a person is using /bin/bash or /usr/bin/zsh. Likewise, a . matches
549	a single character, but in the case of bash and zsh, we need to look at the first and then
550	optionally a second character. The ? character makes the second . optional. Finally, the $
551	anchors the pattern at the end of the string and is also the key for this regular expression.
552	33. A. The different levels of the manual are accessed by preceding the argument with the
553	desired level. The other options, such as --list, do not exist in this context.
554	34. C. The o command opens a new line below the current cursor location. The a command
555	begins an insert mode session at the character after the cursor, not the line. The i command
556	begins an insert mode session at the current cursor location.
557	35. A. Sending -HUP as part of the kill command will restart a process. Of the other options,
558	a -9 will kill the process completely. The other two options do not exist as valid means to
559	kill a process.
560	36. B. The history command will display your command history, including commands from
561	the current session. You can specify how many lines of history to display, as shown in the
562	answer for this question. Note that .bash_history will not show the current session’s
563	history.
564	37. C. The jobs built-in command shows the list of jobs running in the background. Its output
565	includes a job number and the status of the job.38. B. The find command, beginning with the path and then the -name argument, will locate
566	all of the files called .bash_history. The output from the find command should be piped
567	to xargs, which can then build further commands from standard input. Note that this
568	question and solution assumes that all users use the Bash shell and are keeping history.
569	39. C. The tail command provides the end portion of the file given as an argument. Adding
570	the -f option will cause the output to update as new lines are added to the file being tailed.
571	40. D. The nl command will prepend line numbers onto the file given as its argument. The
572	output is then sent to STDOUT. Of the other options, wc -l will print the number of lines
573	in the file but not prepend those numbers onto each line, as was asked for in this question.
574	41. A. The xz command can compress and decompress files in a variety of formats, one of
575	which is lzma.
576	42. A. The find command will be used for this purpose. Adding -type f will limit the search
577	to only files and the -mtime option will limit to modification time in day format.
578	43. C. The mv command is used to move files, and *.txt will look for all files with a .txt
579	extension. Note the fully qualified destination with a / preceding the name tmp.
580	44. D. The pwd command prints the current working directory. The cd command changes
581	directory.
582	45. A. The file needs to first be sorted to group common ZIP codes together. After that, piping
583	the output to uniq will display the unique ZIP codes, and the -c option provides a count.
584	46. A. Preceding the command with a ! will search history and execute the specified
585	command. For example, !vi will start your last Vi session.
586	47. C. The killall command is used to terminate processes using their name.
587	48. C. The ? key will search backward in a file within Vi. The / is used for searching forward.
588	The h key moves the cursor to the left one character, and the x key will delete a character.
589	49. D. The export command makes an environment variable available to subsequent child
590	processes. The other commands shown are not valid.
591	50. B. The echo command sends output and $0 is the parameter that contains the current
592	script name. Of the other options, $PS1 is the shell prompt and the other two options do
593	not exist by default.
594	51. B. The gunzip command is typically used for decompressing files with a .gz extension.
595	The other options are not valid commands.
596	52. C. The -i option causes rm to use interactive mode, where the command will prompt for
597	confirmation prior to taking action. See the (1) rm man page for additional information on
598	the other options.
599	53. A. The find command can be used for this purpose. When used with the size option,
600	various size-related options can be used. The option +1G searches for files greater than or
601	equal to 1GB.54. B. The -v or verbose option lists files as cpio is working with them. Of the other options,
602	-s is swap bytes and –l is used to link files. The -k option is included for compatibility
603	purposes.
604	55. B. The bzcat command sends output to STDOUT from a bzip2 archive.
605	56. C. The jobs command is actually a shell built-in command, meaning that more
606	information is available by using the man page for bash itself. The other options either are
607	not valid or will not show information about the jobs command/built-in.
608	57. B. The nohup command can preface another command when starting so that the process or
609	command will not accept a SIGHUP.
610	58. D. The watch command runs a command repeatedly and displays the output and errors
611	from the command. The pgrep command does not fulfill the needs of this scenario. The
612	mon and procmon commands are not real.
613	59. B. The tmux command creates two (or more) sessions within the same physical terminal
614	window and thus enables this scenario. The screen command can be used to create an
615	additional session, but the screen command does not meet the criteria specified in this
616	scenario, because the scrollback buffer does not capture enough lines by default. The other
617	commands shown are not valid.
618	60. A. The pkill command can be used for the scenario described. The other options are not
619	valid commands.
620	61. A. The -f option matches against the full path. The -d option is used to set the delimiter,
621	the -o option matches the oldest process, and the -i option sets the search to be case
622	insensitive.
623	62. B. The which command is used to determine the command that will be run based on the
624	current environment settings such as the path. The find and ls commands will not work
625	for this purpose.
626	63. B. The unset shell built-in is used for the purpose described. Both the reset and clear
627	commands do not accomplish the task described, and there is no undo command.
628	64. A. The type shell built-in displays information about a given executable. For example, the
629	command type alias shows that alias is a shell built-in as well.
630	65. C. Double quotes help to ensure that variables are interpolated within a shell script.
631	Runquotes are not used for this purpose, and the other options are not valid types of
632	quotes.
633	66. C. The less pager fits the scenario described. The more pager does not have as much
634	flexibility as less. The other options shown are not valid.
635	67. C. The od command converts a file to octal format. The other options shown all have
636	invalid commands.68. B. The -b option for sha256sum and sha512sum reads the file in binary mode as opposed
637	to text mode, which is the default.
638	69. B. The h, j, k, and l keys enable movement of the cursor in command mode Vi.
639	70. C. The decompress and stdout options to xz are functionally equivalent to the xzcat
640	program. There is also a related program called zcat for outputting files compressed with
641	gzip to STDOUT.
642	71. A. The EDITOR environment variable controls the editor that is used. Typical choices
643	include nano, Emacs, Vi or enhanced Vi, known as Vim.
644	72. D. The seventh manual section for regex is found by specifying the level after the command
645	and prior to the manual page to examine.
646	73. B. The renice command changes the priority of a running process. The nice command is
647	not capable of altering running processes, and the other commands shown are not valid.
648	74. B. The fgrep command is equivalent to running the grep command with an -F option.
649	The -f option specifies a file, and the -E option utilizes an extended regular expression and
650	is equivalent to the egrep command. The -a option is important in its own right and causes
651	grep to process a binary file as if it were a text file.
652	75. A. All of the options shown use regular expressions. In the correct answer, the strings
653	Steve and steve will match due to the use of a character class. Option B would match
654	only Steve but, due to the quantifier *, would also match strings like Siwejfiwjfheteve.
655	Option C uses anchoring and thus would only match Steve or steve at the beginning of a
656	line. Option D also uses an anchor to indicate end of line and thus does not make sense in
657	this context.
658	76. C. The top command shows running processes, typically sorted by CPU usage and updates
659	every few seconds. The ps command shows processes but does not auto-update. The nice
660	command sets priority, and there is no procs command.
661	77. A. Files compressed with the gzip utility can typically be read by other operating systems,
662	though it may require additional software for certain operating systems. Compression
663	utilities like bzip2 and xz almost certainly require additional software. The tar command
664	in option D is not a compression utility.
665	78. A. The question mark can be used as a wildcard for such a scenario. An asterisk would
666	also work for file globbing.
667	79. B. The split command can break up a file into multiple pieces. The cut command would
668	split an individual line but does not meet the criteria in this scenario. There is no dice or
669	rem command.
670	80. C. The scheduling priority of the process is shown in the PR column. The process ID is
671	displayed in the PID column. The top command shows CPU utilization in the %CPU
672	column and does not display information about the processor cores.81. A. The d key will be used for this and the number 7 used in order to cut or remove eight
673	lines. Other keys to work with text for cut, copy, and paste in Vi include p, y, dd, and yy.
674	The other options shown for this question are not valid.
675	82. A. The unxz command decompress a file that has been compressed with xz.
676	83. D. The md5sum command creates a 128-bit MD5 message digest. The sha256sum command
677	produces 256-bit values, whereas sha512sum produces 512-bit values.
678	84. A. The paste command fits the scenario described and separates the lines from each file by
679	a tab. The other commands are not valid.
680	85. A. Using a fully qualified path meets the scenario in the most typical manner. You could
681	add the command path to the PATH environment variable, but that is unnecessary given the
682	scenario. Restarting the shell or computer would not have any effect.
683	86. B. The SIGTERM signal is used by default by the pkill command. This can be changed
684	using the --signal option.
685	87. D. Running jobs are listed with the -r option. The -s option displays only stopped jobs,
686	whereas -l shows process IDs. There is no -a option to the jobs built-in command.
687	88. C. The -c option outputs to STDOUT. See the bzip2(1) man page for additional details.
688	1. A. The listing shows a symbolic linked file located in the current directory, linked to
689	.configs/fetchmail/.fetchmailrc. The file is owned by the root user and root group
690	and was created on July 8, 2014.
691	2. A. The mount command is used to mount drives in Linux. The source and destination
692	mount points are expected as arguments. Drive partitions begin at the number 1, making
693	the first partition number 1.
694	3. C. The noexec option will prevent programs from being executed that reside on the
695	partition. The noexec option is used frequently for mounting the /tmp partition.
696	4. B. 0x82 is Linux swap, and 0x83 is Linux. NTFS is 0x07, and FAT is 0.0c.
697	5. B. The partition type 0x83 should be created for a normal Linux partition. Type 82 is used
698	for swap; 84 is an OS/2 partition. There is no L type.6. A. The which command returns the full path to the given command and is useful for
699	determining both whether a given command is available and the location from which the
700	command will run.
701	7. A. The chgrp command can be used to change group ownership of a file. The order is
702	chgrp <groupname> <target>.
703	8. C. The file is almost certainly a hard link to the original script. Although ls won’t show
704	this information, the stat command will show that it is a link and also show the inode to
705	which the file is linked.
706	9. A. The -i option to df produces information on inodes across all filesystems. The ls -i
707	option will produce inode listings, but only for the current directory. The -i option is
708	invalid for du, and dm does not exist as a command.
709	10. C. The -y option will attempt to repair automatically, essentially answering y or yes
710	instead of prompting. Of the other options, only -V is valid and will produce verbose
711	output.
712	11. B. The addition of journaling in ext3 increased filesystem reliability and performance.
713	12. C. The -S option displays output in a format such as u=rwx,g=rx,o=rx. The other options
714	listed do not perform the desired operation.
715	13. B. The -s option to ln creates a symbolic link, or symlink.
716	14. C. The whereis command displays pertinent information about the command given as
717	its argument. For example, entering whereis apache2 on a Debian system will show the
718	binary location, configuration file location, and other relevant details.
719	15. A. The PRUNEPATHS option accepts a space-separated list of paths to remove from the
720	results. The other options listed do not exist.
721	16. D. The /srv hierarchy is used for data for server programs. The /etc hierarchy is
722	configuration information; /var is also data files but variable, such as mail files. The /tmp
723	directory is for temporary files.
724	17. C. The chmod command is used for this purpose, and the u+s option sets the sticky bit for
725	the user on the specified target.
726	18. B. The -a option mounts all filesystems in /etc/fstab that are currently available. This
727	option is typically used if the mount points are not mounted at boot time or another mount
728	point is added to the system after it has been booted.
729	19. B. The mkswap command formats a swap partition. The fdisk command is used to create
730	the partition itself but not format it. The other two options do not exist.
731	20. A. The tune2fs command displays a lot of information about filesystems, and when used
732	with the -l option, the output includes the number of times that the filesystem has been
733	mounted.21. A. The -g option displays progress of the dump. The other options listed do not exist.
734	22. A. The du command will report on disk usage in a recursive manner, unlike the other
735	commands shown here.
736	23. C. The /etc/fstab file is used to store information about the filesystems to mount within
737	the system.
738	24. D. The /media mount point is used for removable media. See https://wiki
739	.linuxfoundation.org/lsb/fhs-30 for more information on the FHS.
740	25. A. The /etc/mtab file contains currently mounted filesystems. Note that /etc/fstab
741	contains filesystem information but doesn’t report which filesystems are currently mounted.
742	26. B. The -r option causes umount to attempt to remount in read-only mode. The -v option is
743	verbose mode, and the -f option forces the operation. The -o option does not exist.
744	27. A. The 022 umask will translate into 644 permissions on a new nonexecutable file.
745	28. C. The updatedb command will update the database used by the locate command.
746	29. A. The type built-in returns the location that the shell will use in order to run the given
747	command. The find command cannot be used for this purpose, and the other commands
748	do not exist.
749	30. B. The -R option will perform the change ownership in a recursive manner.
750	31. D. The proper order is the device (UUID or partition) or filesystem to mount, followed by
751	the mount point or directory to mount that device, followed by its type and options, and
752	then the dump and pass settings.
753	32. A. The blkid command will show partition UUIDs. You can also get this information
754	with the lsblk -no UUID <partition> command. The other commands shown in this
755	question do not accomplish the required task.
756	33. A. Priority order for systemd configuration files are those within the /etc/ hierarchy,
757	followed by files in the /run/ hierarchy, followed by files in the /lib/ hierarchy.
758	34. A. The -y option causes fsck to assume yes instead of prompting when repairing a
759	filesystem. The -v option is verbosity. There is no -m or -x option for fsck.
760	35. C. The -t option sets the filesystem type as ext2, ext3, or ext4. The mke2fs command is
761	typically symlinked from /sbin/mkfs.ext2, /sbin/mkfs.ext3, and /sbin/mkfs.ext4.
762	The -F option forces mke2fs to create a filesystem, and the -a and -e options do not exist.
763	36. B. The file /etc/auto.master contains the configuration for autofs. The other files listed
764	as options are not valid for this scenario.
765	37. C. The mkisofs command creates an ISO filesystem, which can then be written to a CD or
766	DVD. The other commands listed are not valid.38. B. The -c option sets the maximum mount count. The -C option sets the current number
767	of mounts. The -b and -a options do not exist.
768	39. D. The -f option, also known as fake, is helpful for situations where you need to debug the
769	mount process or when you need to add an entry to /etc/mtab for a previously mounted
770	filesystem. The -l option shows labels, and -v is verbose. There is no -q option.
771	40. C. The letters ro indicate that the filesystem has been mounted read-only, meaning that
772	it is not possible to perform a write to the filesystem. The other possible option is rw,
773	indicating that the filesystem has been mounted read-write.
774	41. C. Bad blocks are shown with the -b option. The -f option forces dumpe2fs to perform
775	the requested operation, and the other command options do not exist.
776	42. D. Btrfs is based on the copy-on-write principle and is generally considered more advanced
777	than ext4 and its predecessors. FAT is a legacy filesystem primarily used for DOS and its
778	follow-ons like Windows.
779	43. B. The xfs_info command, which is functionally equivalent to xfs_grow -n, displays
780	information about an XFS-formatted filesystem.
781	44. A. The blkid command shows information about partitions including their type, their
782	UUID, and other basic information. The other commands shown do not exist.
783	45. C. The -t option, which can accept a comma-separated list of types, specifies that only
784	filesystems of the listed type are to be unmounted. This is useful in conjunction with the
785	-a option, which unmounts all filesystems except /proc. The -v option is verbose, and -f
786	forces the operation to continue.
787	46. D. The sync command writes unwritten data to the disk immediately and is useful to run
788	just prior to attempting an unmount operation.
789	47. C. The -f option specifies that xfs_check should check the contents of the named file for
790	consistency. The -v option sets verbosity, and there is no -d or -a option.
791	48. B. The -w option causes debugfs to open the filesystem in read-write mode. There is also
792	a -c option to open in catastrophic mode for filesystems with significant damage. The -rw,
793	-r, and -n options are not valid.
794	49. D. The smartd daemon monitors SMART-compatible disks for notable events and can be
795	configured to send alerts when events occur. The other commands listed are not valid for
796	this scenario.
797	50. A. The -f option forces fsck to run on an otherwise clean filesystem for ext3 filesystems.
798	This can be helpful for times when you suspect there is an error on the filesystem and need
799	to verify the integrity of the filesystem as part of the troubleshooting process. This can also
800	be helpful to prepare the filesystem for conversion, such as might be the case with a tool like
801	btrfs-convert.51. A. The block size for import or restore must match the block size used on export or dump.
802	Block size is specified with the -b option, making option A correct. The other options are
803	not valid for xfsrestore.
804	52. B. A filesystem with the word defaults for its mount options will be mounted read-write
805	(rw), suid, with the ability to have executables (exec). The filesystem will be auto-mounted
806	(auto), but users will not be able to mount it (nouser). Character and block special devices
807	will be interpreted (dev), and operations on the disk will be performed in an asynchronous
808	manner (async).
809	53. B. The btrfs subvolume create command creates a btrfs subvolume. The other
810	commands are not valid.
811	54. C. The -z option sets the maximum size for files to be included in the dump. The -b
812	option sets the block size but is not related to what is being asked for in this scenario. The
813	–s option sets the path for inclusion in the dump, and -p sets the interval for progress
814	indicators.
815	55. C. The -e option sets the behavior, such as continue, remount read-only, or panic, when
816	an error occurs at the filesystem level. The -f option forces whatever operation you’re
817	requesting to continue even if there are errors. The -d and -k options are not valid.
818	56. D. The -n option causes mount to not write to /etc/mtab and is particularly useful for the
819	scenario described. The -a option mounts all filesystems in /etc/fstab. There is no -b or
820	-a option.
821	57. A. The swapoff command deactivates swap space, thereby making it unavailable as virtual
822	memory on the system. The other commands shown as options are not valid.
823	58. A. The Where= directive specifies the location for the final mounted filesystem.
824	59. A. The mkfs.fat or mkfs.vfat commands are valid for creation of FAT filesystems. There
825	is no -f option to mkfs, and there is no mkfat command.
826	60. D. The tune2fs command is used for working with ext2, ext3, and ext4 filesystems. The
827	-j option adds a journal. The other commands are not valid.
828	61. A. The snapshot subcommand of btrfs subvolume creates a snapshot. The other
829	commands shown are not valid.
830	62. A. The -L option forces the log to be cleared or zeroed out, which may cause a loss of
831	data. The -v option sets verbose output; -V prints the version. The -d option performs a
832	dangerous repair, which can be used on a read-only filesystem.
833	63. C. The -o option enables the setting of one or more options for the mount command, and
834	ro is read-only. Note that the -r option will also mount as read-only. The other options
835	shown are not valid.
836	64. B. The -E option signals that an extended option follows, such as stripe_width. The -f
837	option forces an operation but should not be necessary for this solution, and the -e option
838	sets the behavior on error. There is no -extend option.65. A. The gdisk utility is the equivalent of fdisk for working with GPT partitions. Later
839	versions of fdisk can also be used to manage GPT partitions.
840	66. A. The maximum size for a partition on an MBR disk is 2 terabytes. GPT has largely
841	replaced MBR on newer Linux systems.
842	67. C. The -m option with 0 will format the partition with no reserved blocks for superuser or
843	system use. The -r option sets the filesystem revision.
844	68. B. The default time for filesystem reorganization is two hours, or 7200 seconds.
845	69. C. The file permissions are 640, meaning that the group owner can read the file. Therefore,
846	changing group ownership should have the fewest side effects. Granting root access is not
847	preferred, especially noting that the problem statement indicated that granting sudo wasn’t
848	preferred. While using chown on the file to change the owner would also work, it’s likely
849	to have additional side effects that could prevent the owner of the file from reading and
850	writing, and there isn’t enough information in the problem for that. Finally, running
851	chmod 777 is almost never the correct solution to any problem on Linux.
852	70. B. The -a option shows all devices, even those that are empty. The -r option is for raw
853	devices, and the other options do not exist.
854	71. D. USB devices and others removable media can typically be found within the /media/
855	mount point.
856	72. C. The mkfs-related commands are typically used for formatting filesystems on Linux. In
857	this case, mkfs.exfat is the correct option for formatting exFAT filesystems.
858	73. C. The xfs_db command is used for debugging XFS-formatted filesystems.
859	74. C. The -b option is used to specify an alternate superblock and helps in the scenario
860	described, where the superblock has been damaged. The -B option specifies the block size.
861	There is no –s or -o option for e2fsck.
862	75. A. The -h option is the flag for human-readable formatting and shows numerical output in
863	larger size increments rather than bytes. The other options are not valid for df.
864	76. B. The /etc/profile file is one of a few locations in which default options can be set for
865	users of Bash. The other file locations shown do not exist.
866	77. A. A symbolic link will not work. The users would be editing the same file and, without
867	saving as a different filename, would not be able to keep their own edits.
868	78. B. The find command will be used for this purpose, and the -uid option will need to be
869	used because the user has already been deleted. If the user had not been deleted, then the
870	-user option would still work.
871	79. A. The updatedb command is used to update the locate database. The other commands
872	are not valid.80. B. The -f option shows the UUIDs of the filesystems mounted on the system. The -a
873	option shows all devices, the -o option enables specification of output columns, and the -u
874	option does not exist.
875	81. C. The -c option checks for bad blocks before formatting. The other options are not valid
876	with mkswap.
877	82. D. The sticky bit has been set on the file as denoted by an uppercase S.
878	83. C. Using octal form, 4 is user, 2 is group, and 1 is sticky bit. Therefore, 2755 would have
879	setgid for the file.
880	84. C. The -name option is used for this purpose, and / indicates the root of the system. A *
881	wildcard is used to indicate all filenames ending in .sql, as described in the scenario.
882	85. B. The UUID=<UUID> syntax is correct for the /etc/fstab file.
883	86. C. The --inodes option shows inode usage with du. The -h option is human-readable, and
884	-d sets the maximum depth. There is no -i option for du.
885	87. A. The -size option is used with find for this purpose, and the +1G argument will look
886	for files greater than 1 gigabyte. Note that if the + is omitted, only files of the exact size are
887	found.
888	88. B. A symbolic link is the preferred method because it does not require additional
889	maintenance that a script would or that copying would in order to keep the libraries
890	current. Moving the libraries may have unintended consequences if another program is
891	dependent on the libraries in that location.
892	1. B. The PS1 variable usually has its default set in /etc/profile and is used as the shell
893	prompt. Users can customize the prompt to include hostname, working directory, and other
894	elements.
895	2. C. The source command is used to execute commands from a file. A typical use case is to
896	create functions or variables that are then available for use within the current session. The
897	other commands listed do not exist.
898	3. B. While it’s true that every user has a .bash_logout in their home directory, that file can
899	still be edited by the user. Therefore, to ensure that the required command is executed at
900	logout, the /etc/bash.bash_logout file must be used.
901	4. B. The env -u command will unset an environment variable for the current session. The
902	unset command can also be used for this purpose.5. C. The -v option, which is the default, tells unset that the name given is a shell variable
903	rather than a function. The other options shown do not exist.
904	6. A. The alias command is used for this purpose and its format is name=value, making
905	option A correct. The ln command cannot be used for this purpose because it will not
906	accept command-line arguments for the target in such a format, as shown in the options.
907	7. B. User-based configuration files are located in the order .bash_profile, .bash_login,
908	and .profile. Only the first file found is executed and the others are ignored.
909	8. C. The $1 variable is automatically available within Bash scripts and represents the first
910	command-line argument. The other variables listed in this question do not exist by default.
911	9. D. The fi construct is used to indicate the end of an if conditional within a Bash script. In
912	many languages, if conditionals are scoped by braces such as { }, but in shell scripting, fi
913	is used to denote the end of the condition.
914	10. B. The seq command is used to print a sequence of numbers in a variety of formats. The
915	answer for this question provides a starting point (0), and increment (1), and the final
916	number (5), resulting in six numbers being displayed as output.
917	11. B. The echo command is used to display its argument, regardless of whether the command
918	is used inside a shell script or from the command line itself. The env command is used
919	to display environment variables and therefore does not meet the need specified in the
920	question. The var_dump command is used within PHP, and ls is used to display contents of
921	directories.
922	12. A. The suid bit enables the program to run as the user who owns the file regardless of who
923	executes the program. Using SUID is typically not recommended for security reasons.
924	13. D. The exec command executes the command given as its argument and will then exit the
925	shell. The source command does not exit the shell.
926	14. C. The double-ampersand sequence executes commands only if the previous command
927	exited cleanly.
928	15. C. The read command awaits user input and places that input into the specified variable.
929	The exec command is used to execute commands, and the other options are not valid for
930	the purpose described.
931	16. A. Parentheses are used to denote a function, such as myFunction(). The parentheses are
932	optional but are then followed by curly braces containing the commands to be executed
933	when the function is called.
934	17. C. The || sequence indicates an alternate command to run if the initial preceding
935	command does not exit cleanly. The && sequence executes only when the preceding
936	command exits cleanly, so it’s just the opposite of what the question was asking.
937	18. C. The elif keyword is used to create an alternative execution path within a shell script.
938	The other constructs, such as else if and elsif, are used in other languages.19. C. The unalias command is used to remove a previously defined alias. The rm command
939	will remove regular files but not aliases. The other commands do not exist.
940	20. D. At a minimum, you need to be able to read the file being sourced; therefore,
941	chmod 400 will correctly set the permissions. Any chmod that gives additional permissions
942	is not necessary.
943	21. C. The for loop construct in this case will require the variable name LIST to be preceded
944	with a dollar sign ($),making option C correct. The other options will not work for the
945	purpose described.
946	22. C. The -lt operator is used to test for “less than” conditions within a script. The other
947	operators are not valid for use in a shell script.
948	23. B. The -e test checks to ensure that a file exists and is typically used in the context of a
949	conditional within a shell script. The other options may work within shell scripts but are
950	not tests for file existence.
951	24. C. The /etc/skel directory contains files to be copied to the user’s home directory. The
952	other directories listed for this question do not exist by default.
953	25. C. The --norc option causes bash to execute without reading the /etc/bash.bashrc file
954	or the local ~/.bashrc file. The other options listed do not exist as options for bash.
955	26. A. Array creation in a shell script involves parentheses when used in this manner. You can
956	27. C. The -p option to declare displays fully qualified shell statements such that the
957	statements could then be used as input for another command, either through piping or
958	redirection to a script.
959	28. A. The .bash_profile file, if it exists in your home directory, will be executed on login.
960	Note that placing the function in /etc/profile would technically work but then the
961	function would be available to all users, which is not what the question asked for.
962	29. B. The readonly command displays the list of read-only variables that have been declared
963	in the current session. The other commands listed for this question do not exist.
964	30. C. Square brackets are used to denote the beginning and end of the test portion of a while
965	loop in a shell script. Other languages generally use parentheses for this purpose.
966	31. B. The test built-in will return true and can be used to test for the value existence of a
967	variable not being null. Note that the behavior of the test built-in differs depending on the
968	number of arguments.
969	32. C. The HOME environment variable, set automatically to the user’s home directory, is
970	consulted when the command cd ~ is entered. The other paths beginning with HOME do not
971	exist by default, and the MAILPATH environment variable shown contains a list of locations
972	where mail is checked when using the shell interactively.33. B. The TMOUT variable can be set in a given user’s shell and that user will be logged out
973	after the value given (in seconds) of inactivity. The other environment variables listed here
974	do not exist.
975	34. B. Just as with an if statement where the statement is ended with fi, so too is a case
976	statement ended with the word case spelled backward. The curly brace shown as option D
977	is used to close case statements in many languages, but not for shell scripts.
978	35. A. The provided answer performs command substitution and places the value from the
979	resulting command into a variable. Note the use of +%s formatting on the date, which then
980	formats the output as seconds since the epoch, as specified in the question. Option C will
981	provide the date within the DATE variable but will not format it as specified.
982	36. B. Wrapping a variable in curly braces, such as ${FILEPATH}, will ensure that the variable
983	is interpolated or expanded correctly even when used in a place where it might not normally
984	be expanded, such as within a quoted string.
985	37. B. In shell scripts, the commands to execute begin at the do keyword and end at the done
986	keyword. Other languages generally use either curly braces or tabs.
987	38. D. The -r test determines whether a given file exists and can be read by the current user.
988	The -e test only checks to see if the file exists.
989	39. A. The -r option to declare will create or mark the variable as read-only. The -p option
990	prints output in a format that can be reused. The -x option declares the variable for export.
991	40. D. The *) sequence is used to denote a default set of statements that will be executed if no
992	other case matches within the set.
993	41. A. Backquotes can be used for command substitution within a Bash script. The other
994	options shown are not valid for command substitution.
995	42. B. The character sequence done denotes the end of a while loop in Bash.
996	43. B. Greater than or equal to is tested with >=. Of the other operators shown, != tests for
997	inequality.
998	44. C. The execute bit is not set on the script, resulting in the permission denied error, making
999	option C correct. The file extension does not matter, so option A is incorrect. Likewise,
1000	option B is not correct because the script isn’t even executing. Lowercase or uppercase
1001	letters do not matter, making option D incorrect.
1002	45. D. The -f option exports names as functions to child processes. The other options shown
1003	do not exist with the export command.
1004	46. D. The unset command removes a variable from being set. The other options shown do
1005	not exist.
1006	47. A. The /etc/bash.bashrc file is a systemwide configuration file for the Bash environment.
1007	Another systemwide file used for similar purposes is /etc/profile.
1008	48. D. The +x option enables debugging output and is frequently used when debugging shell
1009	scripts. The -x option is used to disable debugging. The -d and +d options do not exist.49. D. The .bashrc file in a given user’s home directory is executed for interactive logins. The
1010	other files shown do not exist.
1011	50. A. The function keyword declares a block of code to be a function in Bash. It’s worth noting
1012	that the function keyword can be omitted in most cases. The other options are not valid.
1013	51. B. The syntax shown in option B is the correct syntax to add a path to the current
1014	environment. Option A does not include the existing path (and will, in fact, overwrite the
1015	existing path). Option C contains spaces, and option D uses a semicolon as a delimiter.
1016	52. D. The $0 variable is automatically defined and contains the name of the script itself. The
1017	other options shown do not exist by default.
1018	53. A. The -s argument enables setting of a delimiter. When used, the numbers will be printed
1019	in a sequence rather than one per line. The -m and -d options do not exist.
1020	54. D. The -O option is used to determine if the user currently running the test is the owner of
1021	the file being tested. The -k option checks to see if the sticky bit has been set. There is no -m
1022	file test.
1023	55. A. A successful return from a command executed within a Bash script is 0. A 1 or higher
1024	typically indicates an error condition. There is no C condition.
1025	56. A. The file is not copied to directories for existing users, making option A correct. There
1026	is nothing in the question to indicate that the file is too big or that it already exists. File
1027	extensions don’t matter in Linux, so option D cannot be correct.
1028	57. C. The find command begins the search in the current directory, which is problematic in a
1029	scripted scenario like the one presented. The find command can find directories, and those
1030	directories can begin with a dot character.
1031	58. B. The -i option ignores the environment. The other options are not valid for use with env.
1032	59. A. The -x option enables debugging when passed on the interpreter line of a Bash script.
1033	The other options are not valid for this purpose.
1034	60. C. Doing math in Bash requires a special syntax. The bc command can also be used for
1035	such operations and is frequently used for math within Bash scripts.
1036	61. A. The read command will be used, and option A shows the correct syntax. Option C
1037	is incorrect because it does not prompt the user. There is no prompt command, making
1038	options B and D incorrect.
1039	62. D. The -n option removes a variable from being exported. The other options do not exist.
1040	63. A. The exit code from the previous command is captured automatically in the $? variable,
1041	thus ruling out any option that did not have this value. A test for the value is done with -eq
1042	in a Bash script, thus making option A correct.
1043	64. D. The source command is frequently used for the purpose described. The function
1044	command can be used to create functions but would not be used for the purpose described.
1045	The include and require commands are not valid.65. B. Adding the execute bit for the user can be done in a non-octal format, as shown
1046	in option B. The only other valid chmod option is 644, which does not grant execute
1047	permission.
1048	66. B. The problem statement specified files, making option B the best answer. Option A will
1049	also find directories.
1050	67. C. The -f option removes a function. The other options do not exist for the unset
1051	command.
1052	68. A. The env command, when used as #!/usr/bin/env bash, will determine the location
1053	of the Bash interpreter automatically. This makes the resulting script more portable for
1054	systems where Bash may not be located in /bin/.
1055	69. B. The front slash, or forward slash, is used for division. Of the other options, an asterisk
1056	is used for multiplication and the other options are not valid.
1057	70. B. The mailx command can be used to send mail from the command line. The other
1058	options shown are not valid commands.
1059	71. D. The -s operator tests if a file is not zero size. The -d operator looks for directories,
1060	whereas -e merely checks if the file exists.
1061	72. A. An alias exists only for the length of the current session, making option A correct. If
1062	the alias or command was invalid, you would have seen it immediately when you created or
1063	used the alias.
1064	73. D. The correct syntax is shown in option D for the scenario described.
1065	74. B. The user is most likely not using Bash but is rather using another shell like Tcsh. The
1066	user could be logging into a different system, but hopefully by having them log out and log
1067	in again that would have been noticed, as would their manual removal of the environment
1068	variables.
1069	75. A. The LOGNAME environment variable contains the currently logged-in user. The other
1070	variables do not exist by default.
1071	76. A. The -h test determines if the file is a symbolic link. The -p option tests if the file is
1072	a pipe, and -S returns true if the file is a socket. The -t test determines if the file is a
1073	terminal.
1074	77. C. The -f option marks a function as read-only. The -p option prints a list of read-only
1075	identifiers. The -a option assumes that the name is an array, and there is no -r option to
1076	the readonly command.
1077	78. B. Option B is the best answer because it will find files where the user permission includes
1078	the execute bit. It’s worth noting that options A and C will find the execute bit but only
1079	with the exact permissions specified.
1080	79. A. The /usr/local/bin directory is the location specified for local binaries according
1081	to the FHS. It’s also a typical place for scripts as well. The /usr/bin and /usr/sbin
1082	directories are for system binaries, and /home/scripts does not exist by default.80. D. Ctrl+c is used to terminate a script and is usually used for terminating programs as well.
1083	81. B. The -0 option follows each environment variable with a null byte rather than a newline.
1084	The other options shown are not valid for use with env.
1085	82. D. In all likelihood, the cp command has been aliased with the -i option. Running
1086	unalias cp will correct the issue. It is possible that the cp command has been recompiled
1087	to always ask for confirmation, but this is not the most likely cause.
1088	83. C. An exit code of 1 usually means error, but in the case of grep it means that the search
1089	pattern was not found.
1090	84. B. The -d test checks if a file is a directory. The -e option checks for existence, and the -a
1091	option is no longer used. The -w test checks to see if a file is writable by the current user.
1092	85. B. The command shown prepends /usr/local/bin on to the existing path. Option A uses
1093	$PATH, which is the incorrect identifier for the left side of the assignment. Option C appends
1094	/usr/local/bin rather than prepends, and option D uses a semicolon as a delimiter.
1095	86. C. The until loop construct will execute at least once before the condition is evaluated.
1096	The while and for loops both evaluate the condition first. The case statement is not a loop
1097	construct.
1098	87. B. The single dot, ., can be used as a means to source environment variables. The other
1099	characters and character sequences do not work for the purpose described.
1100	88. A. The -p option displays all exported variables. The other options shown do not exist.
1101	89. D. The word do indicates the beginning of a while loop in a Bash script. The other options
1102	shown are not valid for the purpose described.
1103	1. A. The greeter is configured through /etc/lightdm/lightdm.conf using the
1104	greeter-session option. The other options provided here are not valid.
1105	2. B. The Screen section of xorg.conf is used to logically bind a given graphics card and
1106	monitor, each of which would be defined in its own respective section in the configuration
1107	file. The other options shown for this question do not exist.
1108	3. A. Frequency options are Hz, k, kHz, M, or MHz, making uHz an unavailable option.
1109	4. C. The systemctl set-default command will be used for this purpose, and the target
1110	of multi-user is used to boot to the command line. You will also need to remove the word
1111	splash from /etc/default/grub and run update-grub as well.5. A. The DISPLAY variable can be used to remotely send the windows of an X session
1112	to another computer when using protocols like SSH. There is no XTERMINAL or XDISP
1113	environment variable, and XTERM is typically a terminal window and not an environment
1114	variable.
1115	6. D. The Welcome option sets the message to be displayed to users within the display
1116	manager when they log in. For remote users, the RemoteWelcome message can be used for
1117	the same purpose.
1118	7. C. The Shift key can be used to enable and disable sticky keys within GNOME and other
1119	operating systems for accessibility purposes.
1120	8. A. The Disable keyword is used to ensure that a given module is not loaded. Note that
1121	a Load statement for the same module takes precedence over the Disable statement, but
1122	Disable can be used to unload modules that are loaded by default.
1123	9. A. The Orca project provides assistive screen reading capabilities within GNOME. Of the
1124	other options given, the screen program is valid but is not used for this purpose.
1125	10. C. The xrandr command can be used to change resolution, and changing the resolution to
1126	something like 800×600 would make icons and other items appear larger.
1127	11. D. The allow-guest option changes the behavior of guest login for LightDM, and
1128	disallowing guest login would generally make the computer somewhat more secure.
1129	However, if someone has physical access to the device, they might be able to get access in
1130	other ways.
1131	12. C. The XFree86 -configure command tells the XFree86 server to query for hardware
1132	and create a configuration for the recognized hardware. Note that you may still need to edit
1133	the resulting configuration file because of unrecognized hardware or to account for specific
1134	configuration items.
1135	13. B. The XkbModel configuration option is used to set the type of keyboard being used, such
1136	as pc105 for a 105-key keyboard. The XkbLayout option defines the layout of the keyboard
1137	such as US for United States–style keyboards.
1138	14. B. The VertRefresh option is used for this purpose and accepts a range of values in the
1139	manner shown. The other options given for this question are not valid for the purpose
1140	described.
1141	15. D. The file ~/.xsession can be used for commands that run X clients. The other files are
1142	not valid for the purpose described.
1143	16. C. The linear acceleration profile is enabled by setting AccelerationProfile to 6 within
1144	xorg.conf. The 0 setting is known as classic, whereas -1 provides constant acceleration (no
1145	profile) and 7 is known as limited, which performs the same as linear but with a maximum
1146	amount of speed and acceleration.
1147	17. A. The /usr/share/fonts hierarchy is used for storage of fonts. Another path that might
1148	contain font information is /usr/share/X11/fonts, but that was not among the choices
1149	given for this question.18. C. Kernel versions beginning with 2.6.26 include native support for Braille displays in
1150	Linux.
1151	19. A. The DontZoom option prevents the specified key combinations from changing the
1152	video mode. Of the other options, the DontZap option changes the behavior of the
1153	Ctrl+Alt+Backspace key combination. The other options don’t have any effect and are not
1154	valid in xorg.conf.
1155	20. C. The xauth program looks for the configuration file in the user’s home directory in the
1156	file .Xauthority. The other files do not exist by default.
1157	21. C. The Xaccess file is used to control access when using XDMCP. The other files are not
1158	valid for this purpose.
1159	22. D. The kmag program magnifies items on a desktop and is used as an assistive technology.
1160	In general, kmag can be used with other window managers as well.
1161	23. A. The SIGTERM signal causes the X server to exit cleanly. SIGKILL would not be a clean
1162	exit. The other signals shown as options are not valid signals.
1163	24. B. The Appearance section of GNOME Control Center is used to set many aspects of how
1164	the desktop appears and behaves, including the choice of a high-contrast theme.
1165	25. B. Mouse gestures are commonly associated with assistive technologies and help to
1166	facilitate uses of programs by moving the mouse in a certain way. Mouse gestures could
1167	be used for login and to capture screenshots, but those are not adequately or generally
1168	descriptive of their use.
1169	26. D. The Alt+Super+S keyboard shortcut activates the screen reader in GNOME 3.9 or later.
1170	The Super+S shortcut enters Overview, and the other shortcuts provided do not have a
1171	special meaning by default. Note that the Super key is also called the Windows key or the
1172	Command key.
1173	27. D. The startx command kicks off the display manager after login to a local terminal. The
1174	other commands shown do not exist or will not work for the purpose described.
1175	28. B. The BlankTime option, which is set to 10 minutes by default, causes the monitor to go
1176	blank but not actually go into standby or other power-saving modes.
1177	29. C. The xwininfo command displays information about a given window within an X
1178	session. The other commands listed for this question are not valid.
1179	30. A. The Mouse button displays keys to move the mouse. The Compose button shows a
1180	compose keyboard, and the other options are not valid.
1181	31. C. The xhost command is used to control access to the X server. A host is added with the +
1182	sign.
1183	32. B. The ForwardX11 option must be enabled on the client in order for X connections or
1184	windows generated from the X server to be sent over an SSH connection.33. D. The FontPath directive provides another location in which the server can find fonts.
1185	The other options do not exist within the context of an xorg.conf configuration file.
1186	34. D. With an on-screen keyboard, users can utilize a pointer such as a mouse to select keys
1187	on the keyboard.
1188	35. C. The XAUTHORITY environment variable can be used to specify the location of the xauth
1189	authority file.
1190	36. B. The Alt+Ctrl+F1 key combination is used to get to a terminal prompt and is helpful in
1191	situations where the X server won’t start properly.
1192	37. B. The autologin-user option is used to define a user who will be automatically logged in
1193	to the system. The other options given in this question do not exist.
1194	38. C. The AccessX utility is used on legacy or older systems to set many of the accessibility
1195	options. The functionality provided by AccessX can typically be found in one of the utilities
1196	provided by the native X window manager, dependent on the window manager in use.
1197	39. A. The export shell command sets an environment variable. In this case, the DISPLAY
1198	environment variable needs to be set. The env command shown will not set the variable.
1199	40. A. The Menus option displays the menu options for a given application so that those
1200	options can be manipulated with the keyboard. The Activate option helps to work with the
1201	desktop and other applications. The other options shown for this question are not valid.
1202	41. B. The /etc/lightdm/lightdm.conf.d directory contains individual *.conf
1203	configuration files for various settings and is typically parsed along with the /etc/
1204	lightdm/lightdm.conf file.
1205	42. B. The COLUMNS environment variable specifies the width in characters of a terminal device.
1206	The other environment variables are not valid.
1207	43. C. The VideoRam option, which can be expressed in bytes, configures the amount of RAM
1208	available to the video card.
1209	44. B. The Depth option sets the color depth for a given monitor display. A typical value might
1210	be 24 for this option.
1211	45. B. The Identifier option provides a unique description of each of the server layouts in an
1212	X configuration. The other options shown for this question do not exist.
1213	46. A. The mkfontscale command will create a fonts.scale file, which describes the outline
1214	fonts on the system and is used for configuration of fonts that are manually added to the
1215	system.
1216	47. A. Display Power Management Signaling (DPMS) enables additional power-saving modes,
1217	such as a full sleep mode, that enable further energy efficiency for the display.
1218	48. B. The emacspeak program provides another visual assistive technology as an alternative
1219	to Orca. The other technologies listed here are not related to visualization or assistive
1220	technologies.49. B. Weston is a reference implementation of the Wayland protocol.
1221	50. C. The SuspendTime sets the time, in minutes, for the monitor to go into standby mode.
1222	The other options shown are not valid.
1223	51. C. The files in /etc/X11/xorg.conf.d/ are included when X is starting.
1224	52. B. XDMCP, which is typically disabled by default, uses no compression or transport
1225	security. XDMCP is therefore not usually preferred for remote access. Of the other options,
1226	SSH offers encryption of the session, and XR and RD are not valid protocols.
1227	53. D. The Xfce desktop environment uses xfwm4 as its window manager. The other options
1228	are not desktop environments.
1229	54. B. The disable-ticketing option turns off simple authentication for clients with Spice.
1230	55. B. Simon is the speech recognition software that is part of the KDE project.
1231	56. D. The only valid panel listed in the options for this question is called Universal Access,
1232	making option D correct.
1233	57. A. The setxkbmap command can be used to enable Xkboptions when X is already
1234	running. The other commands shown do not exist.
1235	58. B. The xrdp program is an open source implementation of an RDP server. The other
1236	programs shown are not valid.
1237	59. A. Changing the VISUAL environment variable to an editor that can run over an SSH
1238	session will fix the issue. In this case, /bin/vim was used.
1239	60. B. The -passwd option is used to set the password on the server for x11vnc.
1240	61. D. The xauth utility is used for working with the X authority file. The other options shown
1241	are not valid.
1242	62. C. Bounce keys cause the interface to not react when keys are accidentally pressed in
1243	succession or held down.
1244	63. B. The TMPDIR environment variable is used if the normal home directory location,
1245	~/.xsession-errors, cannot be opened. The other environment variables are not valid.
1246	64. D. The xdpyinfo command displays various elements about the current display(s) along
1247	with information about X itself.
1248	65. B. The Weston configuration file is called weston.ini and is located in ~/.config. The
1249	other files are not valid.
1250	66. A. The x11vnc program, an implementation of VNC, offers built-in SSL/TLS capabilities.
1251	The other programs shown are not valid.
1252	67. B. The brltty program enables a text-mode braille display. The other programs are not
1253	valid.68. B. The xzoom program is used for screen magnification. The other programs shown are
1254	not valid.
1255	69. D. The GRUB_INIT_TUNE variable can be used within the GRUB configuration in order to
1256	beep when GRUB is ready for input.
1257	70. B. The xhost command will be used for this purpose, and the minus sign removes a host
1258	from being able to connect.
1259	71. B. The Xsession script is executed as the user logging in, making option B correct. The
1260	Xstartup script is executed as root prior to the execution of Xsession. The other files are
1261	not valid as part of the xdm login process.
1262	72. A. The -nolisten tcp option disables listening for TCP connections for an X server. The
1263	other options are not valid.
1264	73. B. SIGHUP is used for the purpose described, typically when a user logs out. SIGKILL does
1265	not restart the server or prepare for a new connection. The other signal names given as
1266	options are not valid signals.
1267	74. C. The greeter-show-manual-login option, when set to true, will require the user to
1268	enter a username for login rather than select the username from a list.
1269	75. B. The -n option disables hostname lookups. The other options shown are not valid.
1270	76. C. In runlevel 3, accessed through the telinit command, the X server is not typically
1271	executed. Runlevel 6 will shut down the system. Runlevel 1 switches to single-user mode,
1272	and runlevel 5 is a multi-user mode in which X is usually running.
1273	77. C. According to the X server documentation at https://www.x.org/releases/X11R7.7/
1274	doc/man/man1/Xserver.1.xhtml, the default location is within the /usr/lib path, but it’s
1275	worth noting that Linux distributions may change this location to be within the /var/log/
1276	hierarchy.
1277	78. B. The ~/.xinitrc file can be used for per-user initialization. The other files are not used
1278	by default for this purpose.
1279	79. C. The -nolisten local option can be added to prevent the X server from listening on
1280	abstract sockets.
1281	80. D. The -broadcast option for XDMCP enables sending of BroadcastQuery packets. The
1282	other options shown are not valid options with XDMCP.
1283	81. C. The gdmsetup program is used to configure various options for the login window and
1284	environment, including those for local and remote users. The other options are not used for
1285	this purpose or do not exist.
1286	82. C. Any host within the example.com domain can connect.
1287	83. C. The family inet6 enables the specified host to connect with IPv6. The other methods
1288	shown will not work.84. B. The ~/.xsession-errors file is the default log file for Xsession and X clients. The
1289	other files are not valid for this purpose.
1290	85. A. The gok command, short for GNOME On-screen Keyboard, is the program to start the
1291	on-screen keyboard. The Caribou program will be the successor to GOK.
1292	86. B. The -f option enables file specification for the X authority file. The -v option enables
1293	verbose output. The other options are not valid.
1294	87. B. Slow keys is the name used to describe this assistive technology.
1295	88. C. RDP listens on port 3389 by default. Port 389 is LDAP, and 3306 is usually MySQL.
1296	1. A. The best option among these choices is to change the group to www-data and change the
1297	permissions such that the group can write into the directory. Option B should never be used
1298	because it enables world-writing to the directory. The other options will not allow the web
1299	server group to write into the directory.
1300	2. B. The format for cron is [minute hour day-of-month month-of-year day-of-week], thereby
1301	making option B the correct option for this question.
1302	3. C. The /etc/localtime file, which can be an actual file or a symbolic link, is used to
1303	indicate the local time zone. The other files listed as options do not exist.
1304	4. D. The LDAP Data Interchange Format (LDIF) is an open format, defined in Request for
1305	Comments (RFC) 2849, that enables import and export of LDAP entries. The file formats
1306	TXT and CSV are valid but not for the purpose described; there is no specific file format
1307	known as LDAP.
1308	5. B. The chage command will be used for this purpose, specifically with the -E option.
1309	When provided with a date, chage will expire the account on that date. When provided
1310	with -1, the expiration will be removed.
1311	6. D. Within the /usr/share/zoneinfo hierarchy, you will find information on the various
1312	regions and time zones available. The files within this hierarchy can be symlinked to /etc/
1313	localtime. The file /etc/timezone is also sometimes used by Linux systems and, notably,
1314	by Java in certain situations.
1315	7. B. The at command is used to run a series of commands that you enter. Unlike with cron,
1316	you can schedule commands from the command line to be executed in the same order
1317	entered rather than having to create a specific script for the commands. The syntax shown
1318	in option B sets the time to be one hour from now.8. B. The userdel command is used for this purpose, and the -r option (lowercase) deletes
1319	both the home directory and mail spool files. The -R (uppercase) option tells the userdel
1320	command to use a chroot directory.
1321	9. B. The /etc/shadow file contains usernames, UIDs, and encrypted passwords and is not
1322	readable by any non-root user on the system due to the sensitive nature of the encrypted
1323	passwords. The /etc/passwd file contains usernames and UIDs but not encrypted
1324	passwords. The other two files listed for this question do not exist.
1325	10. C. Use anacron when you need to schedule a job on a computer that might be off when the
1326	job is scheduled. anacron will take care of running the job at its next available time.
1327	11. B. The +%s option will format the date as seconds since January 1, 1970. This option is
1328	used frequently in scripting and elsewhere for obtaining a unique time stamp that can be
1329	parsed easily as an integer. The other options will not work.
1330	12. C. The --list option shows the available character sets on the system. The other options
1331	given for this question do not exist.
1332	13. C. The LC_TIME environment variable is used to control the display and behavior of the
1333	date and time and can be changed to a different locale in order to achieve the desired
1334	display and behavior of date and time formatting. The other options shown for this
1335	question do not exist.
1336	14. D. Beginning with OpenLDAP version 2.3, slapd-config is used for configuration of
1337	OpenLDAP, as documented at http://www.openldap.org/doc/admin24/slapdconf2
1338	.html. The other commands are not valid.
1339	15. A. The @daily shortcut schedules a job to run at midnight every day. The other options
1340	shown do not exist.
1341	16. B. UTF-8 provides multibyte character encoding and is generally accepted as the standard
1342	for encoding moving forward. ISO-8859 is single byte encoded. The other options are not
1343	valid.
1344	17. A. The groupmod command will be used for this purpose, and the -n option is used to
1345	change the group name. The other commands listed do not exist.
1346	18. D. The /etc/group file contains information on groups on a Linux system. The other files
1347	are not valid for the purpose described.
1348	19. C. The slapcat command dumps the slapd database in LDIF format to STDOUT. The
1349	output can then be redirected into a file. The other commands are not valid.
1350	20. C. The /etc/cron.d/ directory can contain scripts that have scheduling information
1351	within them along with jobs to run. The other locations given as options are not valid.
1352	21. B. The getent command is used to display entries based on the /etc/nsswitch.conf file.
1353	One use case for getent is when integrating with Microsoft Active Directory or another
1354	LDAP service to check if the connection can be made to the LDAP server. The usermod
1355	command is valid but is not used for this purpose, and the other commands shown for this
1356	question are not valid.22. B. The /etc/login.defs file contains various configuration items such as the minimum
1357	and maximum user and group IDs to be used on the system.
1358	23. C. The LC_MEASUREMENT environment variable is used to indicate the measurement units
1359	that should be used.
1360	24. D. The TZ environment variable is used for this purpose and the general format is as
1361	shown, making option D the correct answer.
1362	25. A. The /etc/cron.daily directory contains files such as scripts that are executed daily.
1363	There are corresponding cron.hourly, cron.weekly, and cron.monthly directories that
1364	run on their respective schedules, as indicated by the name of the directory.
1365	26. C. Setting LANG=C is an alias for Portable Operating System Interface (POSIX)
1366	compatibility and will cause programs to bypass locale translations. The other options
1367	shown for LANG are not valid.
1368	27. B. The -m option causes the user’s home directory to be created. By default, if this option
1369	isn’t specified and CREATE_HOME has not been set, the home directory won’t be created. The
1370	–h option displays help text, and the other options shown are not valid.
1371	28. A. The usermod -L command locks an account by placing a ! in the encrypted password.
1372	If the user has another means to log in, such as with an SSH key, using usermod -L will not
1373	prevent their login.
1374	29. C. The LC_ALL variable can be used to set environment variables to the current locale and
1375	will override others. This can be used when there is a need for a temporary change. The
1376	other variables listed here are not used for this purpose and are not created by default.
1377	30. A. The format when adding a username places the username between the schedule and the
1378	command to run, making option A correct. The other options shown for this question are
1379	invalid. In the case of option B, there is no schedule. In the case of options C and D, the
1380	schedule is incorrectly formatted.
1381	31. C. The passwd command will be used for this purpose. The -a option displays all users but
1382	requires the use of -S to indicate status. The -S option alone will not produce a report for
1383	all users, and the --all option is an alias for -a.
1384	32. D. The chage command is used for this purpose. The -d option sets the days since the last
1385	password change and is measured in days since January 1, 1970. The -W option is the days
1386	of warning for changing a password, and the -l option displays a list of the various settings
1387	related to the account.
1388	33. B. The /etc/anacrontab file contains information about the jobs such as the job name
1389	and delay, among other information. The other files listed do not contain anacron-related
1390	information about jobs.
1391	34. D. The ldapadd command is used to add entries to the OpenLDAP database.
1392	35. B. The /etc/cron.deny file contains a list of users who cannot create cron scheduled
1393	tasks. The other files do not exist by default.36. B. The system uses shadow passwords if an asterisk shows up in the password field of the
1394	/etc/passwd entries. There is no indication that the system has been compromised, making
1395	option C incorrect, and there is no password scheme called “forward password aging,”
1396	making option A incorrect as well.
1397	37. D. There is no direct relationship between the UIDs and GIDs on a system. UIDs represent
1398	users, whereas GIDs represent group IDs. On some systems, the UID and GID number will
1399	match for regular users, but this is not a requirement and is more of a coincidence.
1400	38. C. The slapindex command generates indexes based on slapd databases. The other
1401	commands are not valid.
1402	39. A. The usermod command is used for this purpose. The -d option changes the home
1403	directory, whereas -m moves the contents. The other commands shown for this question are
1404	not valid.
1405	40. D. The -G option is a list of supplemental groups to which the user will be added. A
1406	lowercase -g option provides the primary GID. The -l option causes the user to not be
1407	added to the lastlog and faillog databases. There is no -x option.
1408	41. A. The crontab command can be used for this purpose, and the -l option is used to list
1409	the crontab entries. The -u option is needed to specify a user other than the current user.
1410	42. A. The -r option creates a system user that will typically entail no expiration, no home
1411	directory, and a UID below 1000. The -s option defines the shell and is not typically used
1412	for this purpose. The -a and -S options do not exist.
1413	43. B. The /etc/gshadow file contains secure information such as an encrypted password for
1414	groups, where applicable. The /etc/group file contains general information on groups. The
1415	other two files listed as options do not exist.
1416	44. D. The slapd_db_recover command can be used to help recover an OpenLDAP database
1417	that has become corrupted or otherwise invalid. The remaining options for this question
1418	are not valid commands.
1419	45. B. The groupdel command cannot delete groups unless there are no users who have the
1420	given group as their primary GID. There is no -f or -r option.
1421	46. A. The id command shows the username, UID, primary group, and GID, along with
1422	supplemental groups. The passwd and chage commands are not used for this purpose.
1423	There is no getid command.
1424	47. D. The -c option changes the comment field in /etc/passwd. The comment field is
1425	typically associated with the real name of the account. The -R option indicates a chroot
1426	directory, whereas -d indicates a change of home directory. There is no -n option.
1427	48. D. The find command will be used for this purpose. The correct syntax is shown in option
1428	D. The group command will merely look in the specified files for the number 1501, and the
1429	-u option to grep includes byte offsets, which is not applicable for this question.49. A. The standard port for unencrypted LDAP is 389, and that is the port on which slapd
1430	listens for connections. Port 3389 is RDP, whereas 3306 is MySQL. Finally, 110 is POP3.
1431	50. A. The ln command is used for this purpose, and the -s option creates a symbolic link,
1432	and -f forces or overwrites the destination. The other options or order of commands are
1433	not valid.
1434	51. C. The LC_MONETARY variable is used by certain programs to determine the localization for
1435	currency.
1436	52. C. The --on-calendar option adds a timed event with systemd-run. The other options
1437	shown are not valid for use with systemd-run.
1438	53. B. The /etc/cron.allow file is a list of users who have permission to create and remove
1439	their own cron jobs. The /etc/crontab file is used to store cron jobs, and the other files
1440	do not exist.
1441	54. B. Debug level 64 provides configuration processing debug information. Debug level 1
1442	traces function calls, whereas level 8 shows connection management. Debug level 0 is no
1443	debug.
1444	55. C. The atrm command removes jobs given their IDs. The ID can be obtained with the
1445	atq command. The at -l command shown will list jobs but not delete them. The rmat
1446	command is not valid.
1447	56. B. The dpkg-reconfigure command is used to cause the configuration questions to be
1448	asked again. The tzdata package is the name of the package on Debian-based systems. The
1449	two apt- commands shown are not valid.
1450	57. D. There are multiple ways to specify loglevels and debugging for slapd, including by
1451	keyword, by integer, or as shown in the question, by hex. All of the values shown are valid
1452	for loglevel. No debugging is 0, trace is 1, stats logging is 256 or 512 depending on type,
1453	and packets sent and received is integer 16, or hex 0x10.
1454	58. A. The /etc/skel directory contains files that are automatically copied to a user’s home
1455	directory when that user is created. The other directories listed for this question do not
1456	exist by default.
1457	59. B. The atq command shows a list of jobs that have been scheduled with the at command.
1458	The other commands don’t exist with the exception of option D, which shows the at
1459	command but with an invalid option, --jobs.
1460	60. C. The port for LDAPS or LDAP over SSL is 636. Port 389 is standard, non-SSL, LDAP.
1461	Port 443 is used for HTTPS, and 3128 is used for Squid proxies.
1462	61. A. The at command runs a command at a specified time. While cron can be used to run
1463	a command, it will run the command repeatedly according to the schedule set for the
1464	command. The other commands are not valid.
1465	62. D. The /etc/at.allow file is used to specify users who can create at jobs. The other files
1466	are not valid.63. B. Systemd timer files have the extension .timer and are used for scheduling service unit
1467	files or events. The other file extensions are not used for systemd timer units.
1468	64. A. The /var/spool/cron/crontabs directory contains a file for each user who currently
1469	has one or more cron jobs or entries. Note that the other files listed here are not valid for
1470	this purpose.
1471	65. D. The -j option enables specification of a line from which the import will be started. It
1472	is useful in the scenario described where the import needs to be restarted due to error. The
1473	-f option specifies an alternate location for the slapd configuration file. The -q option is
1474	quick mode, with less checking, and -l specifies the input file.
1475	66. B. The -a option shows all locales currently available on a system. The other options do
1476	not produce the output specified in this scenario.
1477	67. A. The --adjust-system-clock option sets the system clock when used with
1478	set-local-rtc. The other options are not valid.
1479	68. A. The -i option displays information that can help determine the character set such as
1480	ISO-8859, ASCII, or Unicode for the given file. The -m option specifies a list of magic files,
1481	-l shows a list of patterns, and -a is not a valid option with the file command.
1482	69. B. The LC_PAPER variable is used to set the paper size for printing. The other variables are
1483	not available by default.
1484	70. C. The /etc/crontab file is a plain-text file that is treated as a systemwide cron file. As
1485	such, the file is generally not associated with any single user and it’s not necessary to run a
1486	special command after editing this file.
1487	71. D. The tzselect command will, by default, display a step-by-step menu to select a time
1488	zone. The eventual output will include a region/time zone line, such as America/Chicago, as
1489	output.
1490	72. A. The OnBootSec option is used for this scenario and option A has the correct syntax.
1491	The other options shown do not exist.
1492	73. B. GECOS is the legacy name for information stored in /etc/passwd such as full name and
1493	other contact information.
1494	74. A. The -g option sets the group ID for the newly created group. The -h option is help, and
1495	neither -k nor -a exists as an option for groupadd.
1496	75. C. The list-timers option shows the currently active timers with systemd. The other
1497	options are not valid.
1498	76. B. The weekly shortcut means that systemd will execute the event once a week. The other
1499	shortcuts given as options are not valid.
1500	77. A. The -r option removes the current crontab. The -i option can be added so that the
1501	user is prompted prior to removal.78. B. The SKEL variable controls the location of the skeleton home directory, which is
1502	normally /etc/skel/ by default. The other options shown are not used for the purpose
1503	described.
1504	79. C. The passwd option is used to list the password database on a system. The other options
1505	do not exist.
1506	80. A. The directory /var/spool/cron/atjobs contains the jobs. The other directories shown
1507	do not exist.
1508	81. C. The GID_MIN variable contains the minimum GID to use on the system. The other
1509	variables are not used for the purpose described.
1510	82. D. The MAIL_DIR variable contains the directory where a user’s mail spool is located. The
1511	other options shown are not valid variables for this purpose.
1512	83. C. The /etc/passwd file contains various information about users on a system such as
1513	username and real name, along with user ID (UID) and login shell. The file is world-
1514	readable.
1515	84. C. The @reboot shortcut indicates that the cron job will be executed when the system
1516	starts up.
1517	85. A. The -r option specifies that the group being added will be a system group.
1518	86. A. The directory /var/lib/ldap stores database files related to the OpenLDAP
1519	deployment on a given server. The other directories shown are not valid for this purpose.
1520	87. A. Only active units are shown by default, so the --all option displays all units.
1521	88. B. The /etc/at.deny file contains a list of users who cannot create at jobs.
1522	1. C. The journalctl command is used to work with the systemd journal. On systemd-
1523	based systems, journalctl is a central command for debugging and troubleshooting.
1524	2. C. The kern facility receives messages from the kernel for logging purposes. Of the other
1525	options, syslog is used for logging messages about syslog itself. The other two options
1526	shown are not valid syslog facilities.
1527	3. D. ntp.org provides a free service for time synchronization. When you use pool.ntp.org
1528	as the target, you will typically receive an NTP server that is geographically close to your
1529	location, or at least as close as possible. Setting your address to 127.0.0.1 or 192.168.1.100
1530	will use a local server but only if that server has an NTP service.4. A. The service used for logging on a computer managed by systemd is called
1531	systemd-journald. You use the journalctl command to view logged entries rather
1532	than the standard Linux toolset.
1533	5. B. The create option is used for this purpose and accepts arguments such as those shown
1534	to set the permissions and ownership. The other options shown are not valid within a
1535	logrotate configuration.
1536	6. D. Configuration files for CUPS are found in /etc/cups. However, it is also common to
1537	manage CUPS through its web interface. The other directories listed are not valid.
1538	7. A. The Allow directive is used for this purpose and the addresses 192.168.1.1 through
1539	.127 signify a /25 in Classless Inter-Domain Routing (CIDR) notation, making option A
1540	correct. Note that option B, with a /24 netmask, would allow the addresses too but would
1541	also allow 192.168.1.128 through .255, which is larger than should be allowed.
1542	8. B. The ntpdate command provides a command-line interface that immediately changes or
1543	sets the time according to the NTP server given as its argument. The ntpd option provided
1544	in option A will run the NTP daemon and would not be appropriate for a script. The other
1545	two commands are not valid. It is worth noting that ntpdate has been deprecated in favor
1546	of ntpd, but you will likely find ntpdate available on many systems.
1547	9. B. Typically, the Connection refused message from an NTP-related command means
1548	that the daemon is not running. There is no indication that the ntpq command is querying
1549	a different server; therefore, whether the network is up or down is irrelevant. The
1550	permission-based options are not valid based on the error message indicated.
1551	10. D. The hwclock command is used to both query and set the hardware clock, such as the
1552	one maintained by the system firmware or basic input/output system (BIOS). The ntpdate
1553	command is used to set the local system time but is not related to the hardware clock. The
1554	other commands are not valid.
1555	11. C. The /usr/share/zoneinfo directory and its child directories contain information on
1556	time zones on a Linux system. The other files and directories do not exist by default.
1557	12. D. The info severity level provides information messages for a given facility. Of the options
1558	given, emerg is used for emergency messages and not normally used by applications,
1559	whereas debug is the highest or most verbose level of logging available through syslog.
1560	13. B. The driftfile configuration option sets the location of the driftfile for ntpd. The
1561	drift file helps to maintain time accuracy. The location shown is the default for Red Hat
1562	Enterprise Linux.
1563	14. A. The mail option is used to send the log to the specified email address on completion
1564	of the logrotate process. The others shown do not exist as options in /etc/logrotate
1565	.conf.
1566	15. C. The journalctl command is used for this purpose, and the --disk-usage option
1567	displays the disk space used by journal log files, which are typically stored in /var/log/
1568	journal.16. D. The mailq command is used on Postfix servers in order to view a summary of the
1569	current mail queue. Details of the queue include the ID of the mail being sent along with
1570	one or more of the email addresses involved in the transaction. The mailq command may
1571	also work with newer versions of sendmail.
1572	17. C. The ntpq command provides an interactive, menu-like interface into the NTP server.
1573	You can use ntpq to check statistics on peers, for example. The ntpdate command shown
1574	as option B is used as a command-line means to set the time. The ntpd command shown as
1575	option A would execute the NTP daemon itself.
1576	18. D. The format is user: destination for the aliases file, making option D correct.
1577	The other options are not valid syntax for the aliases file.
1578	19. B. The -f option indicates the file to which messages will be logged. The -d option is used
1579	for debugging, whereas -v prints the version of klogd. There is no -l option for klogd.
1580	20. A. The chrony package is used for the scenario described and helps with systems that are
1581	frequently offline or disconnected from the network. The other packages listed as options
1582	are not valid for the purpose described.
1583	21. A. The lpr command places a file (or standard input) into the print queue for lpd to work
1584	with. The lpq command prints the current queue. There is no lpx command.
1585	22. C. The -bp option to the sendmail command prints information about the current queue.
1586	There is no -queue or -f option that is relevant for this question. The -bi option is used to
1587	work with the aliases database.
1588	23. A. The -w option sets the hardware clock to the current system time. The -s option does
1589	the opposite, setting the system time to the hardware clock. There is no -a or -m function
1590	for hwclock.
1591	24. D. TCP port 631 is used as the administrative interface into CUPS. Visiting an active CUPS
1592	server on that port will show the administration website for working with print queues and
1593	other configuration items related to CUPS.
1594	25. A. The -q option causes sendmail to attempt to deliver messages from the queue. Add the
1595	-v option to display verbose output.
1596	26. B. The requirements of multiple email addresses prevent the use of .forward; therefore, it
1597	will need to be accomplished in /etc/aliases. The format for multiple email addresses is
1598	to separate them with a comma, making option B correct.
1599	27. A. The --systohc command will set the hardware clock according to the current system
1600	time. The use of --utc is required in order to ensure that the time is set to UTC. If --utc is
1601	omitted, the time will default to whatever was used last time the command was run, which
1602	could be UTC but might also be localtime instead. Therefore, the best option is A.
1603	28. D. The postsuper -d command deletes messages from the queue. The ALL keyword
1604	causes all messages to be deleted from the queue. Care should be taken when performing
1605	this action because it is irreversible. There is no -remove option to postqueue, and the -f
1606	option for Postfix is not relevant. The rm -rf command shown is not specific enough, and
1607	it is generally not recommended to manually remove files from a mail queue.29. A. The URL shown will display the jobs area of the local CUPS server with a query string
1608	name of which_jobs and a value of completed. The other URLs shown are not valid.
1609	30. C. Just as the tail -f command will continuously update the display as new content is
1610	added, so too does the -f option display new entries for journalctl. The -t option shows
1611	messages for the given syslog identifier. There is no -tail or -l option.
1612	31. B. The $UDPServerRun option is used for the purpose described. The port on which the
1613	server should listen is then provided as the value for this option. The other options shown
1614	are not valid configuration items for rsyslogd.
1615	32. A. The postqueue -f command is used to flush the queue. The command will process all
1616	of the emails that are awaiting delivery. The other commands are not valid for this purpose.
1617	33. C. The -g option specifies the maximum offset or skew that can be adjusted for when
1618	synchronizing time. When set to 0, there is no offset check.
1619	34. A. The SystemMaxFileSize option controls the size of the journal log file to ensure that
1620	a log does not cause problems related to disk usage. The SystemMaxUse option controls
1621	overall size of journal files, and the default for SystemMaxFileSize is one-eighth of the
1622	SystemMaxUse setting to allow for rotation of files.
1623	35. C. The lpstat command is used for this purpose. The lpstat command displays
1624	information about printers, print jobs, and related information. The -W option specifies
1625	which jobs to display, complete, or not complete. The lpq command shown as an option is
1626	used to view the queue, and the other options are not valid.
1627	36. D. The postrotate option within a configuration for log rotation can be used for this
1628	purpose. After postrotate, a line typically follows with the script or commands to
1629	execute. The other options shown for this question are not valid.
1630	37. B. SMTP operates on TCP port 25, and if other servers are contacting your SMTP server,
1631	then you’ll need to listen on this port and allow traffic to it as well. Port 23 is used for
1632	telnet, port 110 is POP3, and port 143 is Internet Message Access Protocol (IMAP), none of
1633	which are necessary for SMTP traffic.
1634	38. A. The makemap command is used to create the hashed database in the correct format for
1635	sendmail to use. The other commands are not valid for sendmail.
1636	39. A. The configuration file for syslog-ng is stored in /etc/syslog-ng and is named
1637	syslog-ng.conf. There is not typically an /etc/syslog directory, even on systems
1638	without syslog-ng.
1639	40. C. The application could theoretically use any of the logging facilities, depending on the
1640	type of application being developed. However, the requirement to log to a custom log file
1641	means that the logs will have a different name and possibly location than the standard logs.
1642	Therefore, logging to any of the standard or system-level facilities is not appropriate for this
1643	scenario, making one of the local (local0 through local7) facilities appropriate.
1644	41. B. The usermod command with the -aG option is used to append a group onto the user’s
1645	list of groups. In this case, the user needs to be a member of the lpadmin group.42. D. The nocompress option is used to prevent the log file from being compressed or zipped
1646	as part of the rotation process. This might be needed on systems where compression
1647	negatively affects performance or where additional processing is necessary.
1648	43. C. The cupsctl command should be used with the --share-printers option to enable
1649	printing for remote clients within the same subnet. You would then also flag each printer
1650	for sharing with the lpadmin command, setting the printer-is-shared option to true.
1651	44. B. The mailstats command is used for the purpose described. Of the other options, the
1652	mailq command will display the current mail queue but not statistics on mail that has been
1653	processed. The other two options are not valid commands.
1654	45. B. The --disk-usage option shows the amount of space consumed by active and archived
1655	journals. The other options shown are not valid.
1656	46. A. The systemctl command is used for controlling services. In this case, restart should be
1657	sent to the CUPS service as denoted by the name cups.service.
1658	47. D. The -p option is used to filter based on priority and the loglevel given in the scenario is
1659	debug, making option D correct. The other options are not valid for the purpose described.
1660	48. A. The Port configuration option is used for this purpose and is used as an alternative to
1661	the Listen directive. With the Listen directive, you will specify address:port. However,
1662	option C, while valid syntactically, will listen only on the localhost IP of 127.0.0.1 and not
1663	all interfaces.
1664	49. A. The postsuper command is used for management of various items with Postfix,
1665	including deletion of individual messages from the mail queue. The other commands will
1666	not work for the purpose described.
1667	50. B. The --vacuum-time option will be used for this scenario. Time can be specified in
1668	seconds, minutes, hours, days, months, weeks, and years.
1669	51. B. The file .procmailrc, found in a user’s home directory, is used by Procmail for
1670	processing messages on a per-user basis. The other files are not used by Procmail in a
1671	default configuration.
1672	52. D. The format is local-address: destination-address. Each destination address
1673	is separated by a comma. The difference between options C and D is that the question
1674	specifically asked for addresses @example.com and since the question didn’t specify whether
1675	this server was the server for @example.com, the destination addresses needed to be fully
1676	qualified.
1677	53. D. The postcat command shows the contents of a message from the Postfix queue. The
1678	other commands shown are not valid.
1679	54. C. The /var/log/mail.err file contains errors related to mail delivery. However, on
1680	some systems, mail-related errors may go to a different log, such as /var/log/mail.log
1681	or /var/log/mail.info or similar.55. D. The EHLO command indicates Extended Hello syntax and is followed by the host from
1682	which communication has been initiated. Of the other options, the HELO option is valid but
1683	is not the Extended Hello syntax specified in the question.
1684	56. A. The list-timezones option to timedatectl shows the names of time zones and is
1685	useful for obtaining the correct time zone name. The other options are not valid with
1686	timedatectl.
1687	57. A. The /etc/localtime file is a symlink to /usr/share/zoneinfo/America/Chicago,
1688	making option A correct. Some systems also link /etc/timezone for the same purpose.
1689	58. A. The date command shows the current time zone. The other options shown will not
1690	work.
1691	59. C. The /etc/chrony.conf file is the configuration file used by the Chrony package. The
1692	other files do not exist by default.
1693	60. C. The -k option shows kernel messages only when used with journalctl. The other
1694	options shown do not query the journal.
1695	61. B. The newaliases command re-creates the aliases database on servers running
1696	Postfix, sendmail, and qmail. There is no need to restart the mail server after running
1697	newaliases. The alias command shown in option C will create an alias for the command
1698	shell but is not related to Postfix.
1699	62. D. The systemd-cat command logs to the systemd journal. When given a parameter
1700	such as a command, both STDOUT and STDERR are logged. The other commands shown as
1701	options are not valid.
1702	63. A. The lprm command is used to help manage printer queues by removing jobs. The other
1703	commands shown are not valid.
1704	64. D. The logger command is used to send messages to syslog and can be executed in a shell
1705	script context in order to take advantage of the robustness of syslog without having to write
1706	separate log management into the script.
1707	65. C. The mailq_path parameter contains the path to the mail queue for Postfix. You can use
1708	this to diagnose problems with the queue directories. The other parameters shown are not
1709	valid in Postfix.
1710	66. D. The _SYSTEMD_UNIT filter can be used to show messages related to a single service.
1711	Multiple _SYSTEMD_UNIT arguments can be given to show messages for multiple services.
1712	The other options shown for this question are not valid.
1713	67. C. The lp command, usually used with the -d option to specify the queue name, is used to
1714	add a job to the specified print queue. The other commands shown as options are not valid.
1715	68. B. When the .forward file is found within a user’s home directory, forwarding of email
1716	will typically occur when mail is destined for that user.69. B. The -s option sets the subject for the email to be sent. The -E option informs mail to
1717	not send messages that have an empty body. The -c option enables setting of carbon-copy
1718	(CC) addresses. The -f option specifies an alternate mailbox and would not be used for this
1719	scenario.
1720	70. D. The -s option sets the date and time as specified within the command. If there is
1721	another means to automatically set the date, it may override the change. For example, if
1722	ntpd is running, that process may alter the date even after it has been set with date -s.
1723	71. B. The --vacuum-size option to journalctl will trim the journal data files so that they
1724	consume the specified size. It is worth noting that the size may not be exactly that specified
1725	because journalctl deletes only archived files.
1726	72. A. The --since option filters journal messages based on the time elapsed since that
1727	specified. There is also a corresponding --until option that enables further time filtering.
1728	73. C. The use of - indicates that syslog does not need to sync to disk for every log entry. This
1729	can greatly improve performance for busy systems but may cause log entries to be lost if the
1730	sync process has not been run prior to a system crash or other issue.
1731	74. A. The -P option sends a print job to the specified destination. Of the other options shown,
1732	-h disables banner printing, and the remaining options do not exist for lpr.
1733	75. C. The qshape command displays information regarding the number and age of the
1734	messages in the Postfix incoming and active queues. Other queues can also be viewed using
1735	the command as well. The other commands shown as options for this question are not
1736	valid.
1737	76. D. The SystemMaxUse configuration option configures how much space journal files can
1738	take on the system. The other options shown are not valid, but it is worth noting that there
1739	are several options for controlling journal sizes and these options should be examined as
1740	part of preparation.
1741	77. C. The /var/spool/postfix directory contains directories and files related to the mail
1742	queue for Postfix. The other directories listed are not valid for this scenario.
1743	78. D. The --directory or -D option can be used to specify an alternate location for the
1744	journal data and would support the scenario described. The other options are not valid
1745	with journalctl for the scenario described.
1746	79. C. The /var/log/ directory is the normal location for system logs, and daemons will
1747	typically use this hierarchy for logs as well. For example, some Linux distributions use
1748	/var/log/journal/ for systemd journals. The other directories shown as options do not
1749	exist by default.
1750	80. C. The :blackhole: option can be used as a destination to prevent Exim from delivering
1751	the mail for that particular user or email account. The other options shown for this
1752	question are not valid.
1753	81. C. The <DefaultPrinter printerName> stanza, where printerName is the name of the
1754	printer, configures a printer for CUPS.82. C. The lprm command can be used for this purpose and, when given a single dash, will
1755	delete all jobs from the queue if run as root. The other options given for lprm are not valid.
1756	83. B. The -r option enables setting the From header of the email to be sent rather than the
1757	currently logged-in user. The -f option specifies a different mailbox and is not useful for
1758	this scenario. The -o and -m options do not exist.
1759	84. B. The @@ symbol specifies that TCP should be used rather than the default @ that normally
1760	precedes a host using UDP for remote logging.
1761	85. C. The Storage=Persistent key/value pair within the [Journal] stanza of the
1762	configuration file enables persistent storage for the journal. The other key/value pairs are
1763	not valid.
1764	86. A. The chronyc command can be used for monitoring the status of time updates. The
1765	other options shown are not valid commands.
1766	87. C. Individual configuration files for various log file rotation policies are found in
1767	/etc/logrotate.d. This directory is included in the primary configuration file
1768	/etc/logrotate.conf.
1769	88. A. The postqueue -p command and option view the pending queue. The postqueue -f
1770	command causes the queue to be flushed. The other commands shown are valid, but their
1771	options are not.
1772	1. A. The netstat command can be used for this purpose, and the -r option displays
1773	the current routes. The addition of -n prevents DNS lookups, which can help with
1774	performance.
1775	2. A. The ifconfig command will be used for this purpose and requires the addition of
1776	the -a option because the adapter is currently down. The ifup command can be used to
1777	bring up an interface but does not display information by default. The netstat command
1778	displays information about the network but not with the -n option.
1779	3. D. Private IP addresses are found within the 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16
1780	ranges, making an address in the 143 range a public IP.
1781	4. C. The route command is used for this purpose, and adding a route is done with the add
1782	option. The default gateway is added using the default gw keywords followed by the IP of
1783	the gateway and the adapter.
1784	5. A. The host command enables changing of the query type with the -t option. Using ns as
1785	the type will query for the name servers for a given domain. There is no all type, and the
1786	other options are also invalid.6. B. Traditionally, udp/53 is used for DNS queries, but with a primary and secondary server
1787	it is assumed that zone transfers may occur. DNS zone transfers typically take place over
1788	tcp/53.
1789	7. B. The -I option enables the choice of interface. A lowercase -i option sets the interval,
1790	whereas -a indicates an audible ping. Finally, -t enables a time-to-live (TTL)-based ping
1791	only.
1792	8. D. A /27, with a netmask of 255.255.255.224, splits a subnet into four segments of 32
1793	addresses, thus enabling 30 usable addresses.
1794	9. A. The host or dig commands can be used for this purpose by setting the type to mx. The
1795	mx type will query for the mail exchanger for the given domain. There is no smtp type.
1796	10. B. The localhost address for IPv6 can be written as ::1. Addresses shown like 127 represent
1797	the IPv4 localhost range but are not written properly for IPv4 or IPv6.
1798	11. A. The -T option causes traceroute to use TCP packets. This option, which requires root
1799	privileges, can be helpful for situations where a firewall may be blocking traceroute traffic.
1800	The -i option chooses the interface, whereas -s chooses the source address. A lowercase -t
1801	option sets the Type of Service (ToS) flag.
1802	12. C. The ifup command is used to bring up network interfaces, and the -a option brings
1803	up those interfaces marked as auto. Likewise, ifdown can be used to turn off network
1804	interfaces. The ifconfig -a command displays information on all interfaces, and there is
1805	no ifstat command.
1806	13. D. The hostname command is used to return the hostname and domain. When given the
1807	-d option, just the domain name is returned to STDOUT, thereby making it appropriate for
1808	use in a script.
1809	14. A. The ip command with the monitor option/subcommand will display netlink messages
1810	as they arrive. There is no netlink subcommand for ip, and the route command will not
1811	work for this purpose.
1812	15. D. The -6 option, as in traceroute -6, executes an IPv6 traceroute. The other options
1813	shown for this question are not valid. It would be rare for the traceroute6 command to
1814	not be available and still have the traceroute -6 command available.
1815	16. A. The syntax is database: databasename with additional database names separated by
1816	spaces, as shown in the correct option for this question.
1817	17. A. The @ symbol is used to indicate a server to which the query will be sent directly. This
1818	can be quite useful for troubleshooting resolution problems by sending the query directly to
1819	an authoritative name server for the domain. Of the other options, -t sets the type and the
1820	others are not valid.
1821	18. D. SNMP traffic takes place on ports 161 and 162. Though the traffic is usually on UDP,
1822	the TCP ports are also reserved for SNMP. Ports 110 and 143 are used for POP3 and
1823	IMAP, respectively, whereas 23 and 25 are telnet and SMTP. Finally, ports 80 and 443 are
1824	HTTP and HTTPS.19. A. The getent command is used for working with NSS databases, and getent hosts will
1825	display the available hosts using the databases configured in /etc/nsswitch.conf.
1826	20. D. A /25 in CIDR notation represents half of a /24 in address space, therefore
1827	making 255.255.255.128 the masked bits. The 255.255.255.0 option is /24, whereas
1828	255.255.255.192 is a /26. Finally, 255.255.0.0 is a /16.
1829	21. C. The configuration option is called nameserver, and the value for the option is the
1830	IP address of the desired name server. There are several options that affect how name
1831	resolution is performed, such as the number of attempts and timeout. Also, the order
1832	in which name servers appear affects in which order the name servers are queried. See
1833	resolv.conf(5)for more information.
1834	22. D. The /etc/services file contains standard port-to-protocol information based on the
1835	well-known and assigned ports from the Internet Assigned Numbers Authority (IANA). If
1836	you’d like to provide a custom name for the service, you can do so by editing this file. There
1837	is no /etc/ports or /etc/p2p file by default, and /etc/ppp is usually a directory for the
1838	Point-to-Point protocol daemon and related services.
1839	23. A. The route command can be used for this purpose, and the syntax includes the network
1840	range, denoted with the -net option, followed by the word netmask and the masked bits,
1841	followed by the lettersgw and the IP of the gateway. The other options shown are invalid for
1842	a variety of reasons, including missing keywords and options and order.
1843	24. C. The -a option displays statistics for each socket, both listening and non-listening.
1844	Included in this information is the send and receive queues. This information can be used to
1845	gauge performance and potential bottlenecks.
1846	25. A. The correct format is the IP address followed by canonical hostname followed by any
1847	aliases for the host. You can use entries in /etc/hosts to override DNS lookups, which can
1848	be useful to prevent those names from resolving or to provide a different resolution.
1849	26. C. The ifconfig command for configuring interfaces begins with the device followed by
1850	the IP address, which is then followed by the netmask keyword and the netmask you want
1851	to add. Because this is a /24, the netmask is 255.255.255.0.
1852	27. C. IPv4 addresses are 32 bits in length and IPv6 addresses are 128-bits. Both IPv4 and
1853	IPv6 can be used on internal and external networks alike, and subnetting is indeed
1854	necessary with IPv6.
1855	28. D. ICMP is a layer 3 protocol, meaning that it does not use ports for communication.
1856	TCP/43 is used for whois whereas port 111 is used for sunrpc. UDP/69 is used for the
1857	TFTP protocol.
1858	29. B. The ip route command can be used for this purpose, and its syntax uses a change
1859	command and the via keyword. The same operation could be completed with the route
1860	command but would require deleting the existing gateway first and then re-adding a new
1861	default gateway.
1862	30. C. Secure Shell (SSH) operates on TCP port 22 by default. TCP/23 is used for telnet,
1863	TCP/25 is used for SMTP, and TCP/2200 is not associated with a well-known service.31. B. The nc command is used to start netcat and the -l option causes it to listen. The -p
1864	option is used to specify the port on which netcat will listen. The -s option specifies the
1865	local source address and is not used for this scenario.
1866	32. A. The soa type is used to query for Start of Authority records for a domain. Note that
1867	in many cases, dig will attempt to look up the domain within a given command and
1868	may not appear to have had an error. For example, when running option D
1869	(dig -t auth example.com) you will receive information about example.com and
1870	there will be a line in the output that dig has ignored the invalid type of auth.
1871	33. A. The search option is used for this purpose and can be provided with multiple
1872	domain names, each separated by a space or tab. The domain option is valid within
1873	/etc/resolv.conf but does not allow for multiple domain names. On newer systems,
1874	systemd-resolved has taken over for the /etc/resolv.conf file.
1875	34. C. The ping6 command is used to ping IPv6 addresses. Unique local addresses are the IPv6
1876	equivalent of RFC 1918 private addresses in IPv4. In IPv6, fc00::/7 is the unique local
1877	address space. Note that there is no -6 option to the normal ping command.
1878	35. A. The route command can be used for this purpose, and in the scenario described, a
1879	reject destination is used for the route. The other options shown are incorrect because
1880	they use invalid options to the route command.
1881	36. B. The tracepath command provides the maximum transmission unit (MTU) of the hops
1882	where possible. Both traceroute and tracepath can be used internally or externally,
1883	and both provide IPv6 capabilities, though traceroute6 and tracepath6 provide IPv6
1884	capabilities as well. Certain options with the traceroute command can require root
1885	privileges, but not enough information was given in the question for that to have been the
1886	correct option.
1887	37. D. The -c option provides the count of the number of pings to send. The -n option
1888	specifies numeric output only, whereas -p specifies the pattern to use for the packet content.
1889	Finally, the -t option sets the TTL.
1890	38. A. The nmcli command provides a command-line interface suitable for working with
1891	NetworkManager through a terminal or SSH connection. The nmtui command provides a
1892	curses-based interface that also works through a terminal or SSH connection.
1893	39. A. The syntax for ifconfig uses the device—in this case followed by the protocol inet6—
1894	and then the keyword add to indicate that an additional IP address is being added, followed
1895	finally by the address itself.
1896	40. C. LDAP over SSL, or LDAPS, operates on port 636. Port 53 is used for DNS, port 389 is
1897	used for normal, non-SSL LDAP, and port 443 is used for HTTP over SSL.
1898	41. D. The best option for this question is to add an entry for the host in /etc/hosts. Doing
1899	so will always cause DNS queries to resolve to 127.0.0.1. The other options are not as
1900	robust because they rely on www.example.com always having the same IP address, or the
1901	solutions require additional maintenance to constantly add new IP addresses if
1902	www.example.com’s IP address changes.42. A. The ip route flush cache command should be executed after changing the routes.
1903	The other commands shown for this question are not valid.
1904	43. A. SPF records are stored in the txt record type in DNS, making -t txt the correct option
1905	for this. Of the other options, only -t mx is valid and returns the mail exchangers for the
1906	given domain.
1907	44. B. TCP is a connection-oriented protocol that uses a three-way handshake to establish a
1908	connection. ICMP does not use ports for communication, and UDP is connectionless. IP is
1909	the core Internet Protocol and does not use a handshake.
1910	45. D. There are 1,048,576 IP addresses in the 172.16.0.0 private range. There are 16,777,216
1911	in the 10.0.0.0 range and 65,536 in the 192.168.0.0 range.
1912	46. C. The only viable possibility of those listed is that ICMP traffic is blocked. TCP traffic is
1913	obviously passing because of the ability to get there using HTTP, and DNS must also be
1914	working.
1915	47. C. The G signifies a gateway within the route table.
1916	48. A. The axfr type is a zone transfer, and the @ symbol signifies the server to which the query
1917	will be sent. There is no xfer type, and option B is just a normal query for the domain sent
1918	to the specified server.
1919	49. D. The netstat -s command displays aggregate statistical information for networking,
1920	including the total packets received and the number of packets forwarded. The ifconfig
1921	command does not show packets forwarded. The ls command is not used for networking,
1922	and the ipstat command does not exist.
1923	50. C. The ip command defaults to the inet family if not otherwise specified with the -f
1924	option. The command will attempt to guess the correct family and fall back to inet.
1925	The other families listed as options for this command are not valid for use with the ip
1926	command.
1927	51. B. The ifconfig command will be used for this purpose, followed by the interface. The
1928	hw keyword is used for the hardware address, which is then followed by the hardware class,
1929	in this case ether. That is followed by the new MAC address (not depicted in the options).
1930	The other commands are not valid.
1931	52. D. The -n option causes route to use numeric values only, performing no name resolution.
1932	This option is useful for the scenario described. The -e option causes the output to be in
1933	netstat format. There is no -d or -f option for the route command.
1934	53. A. Because we’re working with MAC addresses, the arp command will be used. The -d
1935	option removes or deletes an Address Resolution Protocol (ARP) entry, which would be
1936	appropriate here so that the MAC address resolution occurs again. The netstat command
1937	will not be used for this purpose. The hostname and dig commands work with name
1938	resolution but not for MAC addresses or the ARP table.54. A. The iw command will be used for this purpose. When using iw with a specific device,
1939	the dev keyword appears next, followed by the device name and then the command you
1940	want to execute on that device. In this case, the link command is used.
1941	55. B. The iwconfig command, which is similar to the ifconfig command, works with an
1942	individual wireless interface to set and display parameters. Of the other commands, the
1943	ifconfig command is valid but not used for wireless. The other commands are not valid.
1944	56. C. The iwlist command will be used for this purpose, and the scan subcommand is used
1945	to look for local access points and wireless networks. Superuser privileges are required for a
1946	full scan. The iwconfig command does not have a scan subcommand. Likewise, there is no
1947	subcommand called get for the iwlist command, and there is no iw-scan command.
1948	57. B. NTP listens on UDP port 123 by default. Ports 20 and 21 are used for FTP services,
1949	port 139 is used by NetBIOS, and port 5150 is not usually used.
1950	58. B. The mtu can be used to set the value for the maximum transmission unit (MTU) for
1951	a given interface. The metric option sets the interface metric. The other options are not
1952	valid.
1953	59. A. The -s option creates an ARP table entry. The -d option removes an entry. The -c and
1954	--add options do not exist.
1955	60. A. The ss command provides many of the same functions as netstat but can show some
1956	extended information, such as memory allocation for a given socket. The free command
1957	shows memory usage but not by socket, and the other two commands do not exist.
1958	61. D. The -f option is a flood ping. This will effectively cause the interface to send and receive
1959	large amounts of traffic, usually making it easier to find on a switch. The -a option is an
1960	audible ping, emitting a sound on ping. The -c option sends a certain count of pings, and
1961	there is no -e option.
1962	62. B. The netcat command provides a method for opening and communicating on both
1963	sides, server and client, for a TCP connection. The netcat command avoids some of
1964	the issues with telnet capturing characters specific to the Telnet protocol. The netstat
1965	command does not test connectivity, and ping does not do so at the TCP level. There is no
1966	nettest command.
1967	63. C. The -D option lists the interfaces on a given computer. The -d option dumps compiled
1968	matching code, and -i selects an interface. There is no -a option.
1969	64. A. The ping6 command performs the same as the IPv4 ping command but does so for
1970	IPv6. The other commands are not valid on Linux.
1971	65. B. The ip command can be used for this purpose. When using it with the addr object
1972	and the -6 option, only information about IPv6 addresses will be shown. The first option,
1973	simply ip addr, will show all addresses, including IPv4. The other commands are not
1974	valid.66. A. The ifconfig command will be used for this purpose, and ARP can be disabled by
1975	preceding the word arp with a minus sign, as shown. If no minus sign is present, then ARP
1976	will be enabled. The other commands will not work for this scenario.
1977	67. C. The dev option specifies the device to use for the route being specified. This is a typical
1978	use case for many routes to reduce the chance of the kernel guessing incorrectly. The other
1979	options shown for this question are not valid.
1980	68. C. The -p option shows the process IDs associated with a given socket within the ss
1981	output. The -a option is all sockets, whereas -l is listening sockets. The -f option is used to
1982	specify the protocol family.
1983	69. C. The -I option tells traceroute to use ICMP for requests. The -T option is TCP SYN.
1984	The -A option performs AS path lookups, and the -i option configures traceroute to use
1985	the specified interface.
1986	70. C. Internally, the hostname command uses gethostname. This can be useful to know when
1987	troubleshooting address resolution issues such as conflicting results for host naming. The
1988	other functions are not valid.
1989	71. A. The grep command used with the -i option makes the grep case insensitive. When
1990	used with the -v option, grep will exclude the argument, thus doing the opposite of what’s
1991	needed here. The kernel ring buffer will probably not contain information about DHCP,
1992	making dmesg an incorrect option.
1993	72. B. Only alphanumerics, minus/dash, and dot are valid for hosts in /etc/hosts.
1994	73. B. Options within /etc/resolv.conf are preceded with the options keyword followed by
1995	one or more options, such as debug.
1996	74. D. The journalctl command will be used for this purpose. Adding the -u option specifies
1997	the unit for which journal entries are desired.
1998	75. A. The /etc/hostname file typically contains only the hostname of the local computer
1999	rather than the hostname and domain name. This is then read at boot time to set the
2000	hostname for the computer. The /etc/hosts file contains information on various hosts for
2001	name resolution purposes. The other files do not exist.
2002	76. B. The traceroute6 command is used for tracing IPv6 routes. The other commands do
2003	not exist.
2004	77. D. The axfr type can be used with dig to request a zone transfer. The client from which
2005	you request the zone transfer will need to be authorized to initiate a transfer.
2006	78. A. Setting -a as an option to the host command sets the query type to ANY. The -c option
2007	sets the class, and -d turns on debugging. There is no -b option.
2008	79. C. The .digrc file, when created in a user’s home directory, can be used to set defaults for
2009	use of the dig command. There is no dig configuration file found in /etc.80. D. POP3 servers do not have a specific type in DNS. MX type indicates mail exchanger, or
2010	SMTP server.
2011	81. A. The ip addr add command is used to add IP addresses to interfaces using the syntax
2012	shown in option A. The other options do not have the correct syntax.
2013	82. B. The resolvectl command is used for assistance with resolution issues for
2014	systemd-resolved and, when given the status command, will return the DNS
2015	settings. The other options shown do not exist. The resolvectl command is somewhat
2016	new, and if it’s not yet available on a given systemd-based distribution, then
2017	systemd-resolve --status can be used.
2018	83. A. The nmcli command is the only valid NetworkManager command shown as an
2019	option, and when given the networking on command, NetworkManager will control
2020	the network interfaces. It is worth noting that if you disable NetworkManager control
2021	with networking off then all of the previously managed interfaces are disabled.
2022	84. B. NXDOMAIN is the status for a nonexistent domain or host, basically that the host for
2023	which the query was sent does not exist. A normal status when there has not been an error
2024	is NOERROR.
2025	85. C. The systemd-networkd daemon can be used to manage networking through systemd.
2026	The other options shown are not valid.
2027	86. B. The set-hostname command within hostnamectl sets the hostname of the device. The
2028	other commands shown are not valid for use with hostnamectl.
2029	87. A. IMAPS uses port 993 by default, as defined by IANA. Port 995 is POP3S, port 465 is
2030	SMTPS, and port 514 is used by syslog.
2031	88. B. The -o option removes newlines from the output, making the output more suitable for
2032	the grep command. The -l option specifies the number of loops for the ip addr flush
2033	command, the -f option specifies the protocol family, and there is no -n option.
2034	1. A. If /etc/nologin exists, users will be prevented from logging in to the system. The root
2035	user can still log in, assuming that root logins are enabled within the ssh configuration.
2036	2. B. The find command will be used for this purpose, and the permission can be described
2037	as 4000 to indicate the presence of the setuid bit. The -type option can be used to change
2038	the type of object to be returned but is not relevant for the scenario described.
2039	3. B. The lsof command can be used for this purpose and, with the -i option, will display
2040	the network ports along with their process. The netstat command, when run with the
2041	-a option, will display network ports but not the process. The ps command is used for
2042	processes but not network ports. Finally, there is no netlist command.4. A. The fuser command can be used to determine which process is using a given file. The
2043	ls command will show files and find can be used to find files but not specifically for this
2044	purpose. The ps command does show processes but not necessarily ones tied to a particular
2045	file.
2046	5. D. The chage command is used for working with account aging information such as
2047	expiration date, password change, days between password changes, and so on. The -l
2048	command lists information for the given account. The usermod command is used to make
2049	changes to an account, and the other two commands are not valid.
2050	6. A. The nmap command is used to scan for open ports. By default, the nmap command will
2051	scan for open TCP ports to the address or addresses specified. The other commands shown
2052	do not scan for open ports to external (off-host) IP addresses.
2053	7. B. The ssh-keygen command is used to create a key pair for use with ssh instead of a
2054	password. Of the other options, the ssh command does exist but the -k option is used
2055	to disable Generic Security Service Application Program Interface (GSSAPI) credential
2056	forwarding and not for the purpose described.
2057	8. B. The format is username (or other specifier) followed by hard or soft, depending on the
2058	limit type, then the keyword followed by the value for that given keyword.
2059	9. A. The authorized_keys file, stored in the .ssh directory in your home directory,
2060	contains public keys that are authorized to log in to the server using their corresponding
2061	private key.
2062	10. C. The -p option shows the process ID to which a given port is connected and is useful
2063	for displaying information about which process is listening on a given port. The -a option
2064	shows listening and nonlistening sockets whereas -n disables name lookups. The -l option
2065	shows listening sockets only.
2066	11. D. Loading alternate files is accomplished using the -f option. Doing so facilitates exactly
2067	the scenario described, being able to examine logins from old log files. The -a option
2068	controls the location of the display for the host, whereas -t controls the display to output
2069	the logins as of the specified date and time. There is no -e option.
2070	12. D. The w command shows currently logged-in users along with information such as uptime
2071	and load average. The fuser command is used to show open files, and the -u option to ls
2072	controls the display for file listings. There is no listuser command.
2073	13. A. The -u option is correct for this purpose. An uppercase -U option sets the user context
2074	for listing privileges. The -s option sets the shell, and the -H option sets the home directory.
2075	14. B. The NOPASSWD option causes sudo to not prompt for a password for a given sudo
2076	command. This is useful for scripted scenarios where a password prompt would cause
2077	problems.
2078	15. C. The ulimit command shows such limits, and the -a option shows all limits for the
2079	currently logged-in user. The other commands are not valid.16. C. The syntax to block access to every service uses the ALL keyword followed by the
2080	address or network to which the policy will apply.
2081	17. A. The correct format is YYYY-MM-DD for the usermod command.
2082	18. C. The disable option is used for the purpose described, and can be set to yes or no. The
2083	other options are not valid for this scenario.
2084	19. A. The file is named id_rsa by default, and the public key is named id_rsa.pub. For DSA
2085	keys, the names are id_dsa and id_dsa.pub. Other key names such as id_ecdsa, id_
2086	ecdsa.pub, id_ed25519, and id_ed25519.pub are also used depending on the algorithm.
2087	For client keys, these are typically stored in ~/.ssh/ by default.
2088	20. C. The -c option executes a single command but does so without an interactive session.
2089	The -s option specifies the shell to be used. There is no -u or -e option for the su
2090	command.
2091	21. A. The /etc/security/limits.conf file (on some Linux distributions this file could be
2092	/etc/limits.conf) enables the setting of limits for user logins, processes, memory usage,
2093	and other resources. The other files shown do not exist by default.
2094	22. B. There is no special option necessary in order to execute a single command on a remote
2095	host with ssh, although you might sometimes place the command in quotes if spaces are
2096	included. The -s option requests a subsystem and is not related to this scenario. The -e
2097	option specifies an escape character.
2098	23. D. The ssh-add command is used to list currently loaded keys and is used in conjunction
2099	with ssh-agent. There is no -l option to ssh-agent, and the -l option to ssh specifies the
2100	login name to use. There is no ssh-list-keys command.
2101	24. C. While any text editor can be used, it is highly recommended that you use the visudo
2102	command to edit /etc/sudoers. Using visudo enables syntax checking, which will help to
2103	prevent issues with an invalid configuration, causing problems for those who rely on sudo.
2104	25. A. The systemctl command will be used for this purpose, and the subcommand is
2105	disable. There is a stop subcommand, but it will only stop the given service rather
2106	than prevent it from starting on boot. The other options are invalid for various reasons,
2107	including that they use systemd as the command name rather than systemctl.
2108	26. B. The chage command can be used for this purpose, and the -E option accepts days since
2109	1/1/1970. There is no -e option to passwd, and -l for usermod will not perform the action
2110	described. There is no chguser command.
2111	27. C. The GlobalKnownHostsFile configuration option enables the specification of a server-
2112	wide known hosts file, thus preventing users from needing to accept host keys for the hosts
2113	specified therein.
2114	28. C. The maxlogins parameter is used to control the number of simultaneous logins for a
2115	given account.29. B. The ssh_known_hosts file, typically kept in /etc/, is used for the purpose described.
2116	Note that on some systems, this file and other SSH-related configurations may be found in
2117	/etc/ssh/. The options that indicated ~ or within /root are incorrect because the question
2118	specified a server-wide list.
2119	30. C. The date of the last password change, as measured in days since January 1, 1970, is
2120	contained in the third field of a shadow entry. The expiration date would be the 8th field, as
2121	separated by colons.
2122	31. A. The format for local forwarding uses the -L option followed by the local port and then
2123	the remote host:port combination. This is typically followed by the user@host credential
2124	and destination information for the SSH connection itself.
2125	32. C. The option is called X11Forwarding and it must be set to yes in order for the
2126	destination server to forward X-based windows to the local client computer. The other
2127	options shown are not valid.
2128	33. A. The --gen-key subcommand is used for the purpose described. The other options
2129	shown do not exist.
2130	34. A. The --sign option is used to sign files and documents with gpg. The other options
2131	shown are not valid for signatures.
2132	35. A. The -p option sets the port for login and is useful for scenarios where you cannot use
2133	the host:port syntax. There is no -P or @ option with ssh, and the -l option specifies the
2134	login name.
2135	36. A. The -s option sets the type of scan and, when followed by an uppercase S, sets the
2136	option to SYN. The T option is a Connect() scan. There is no Y or -type option for nmap.
2137	37. C. The wtmp file, stored in /var/log, is used to store recent login information and must be
2138	read with the last command due to its format. The other logs listed for this question are
2139	not default logs found on a Linux system.
2140	38. A. The -i option for ssh is followed by the private key to use for authentication. Doing
2141	so implies that the public key is in the authorized_keys file on the remote host. The -k
2142	option disables sending of GSSAPI credentials, whereas -f is used to request backgrounding
2143	of ssh. There is no --key option.
2144	39. A. The -n option facilitates the scenario described and will exit non-zero rather than
2145	prompting. The -i option sets the login name and is not valid for this scenario. The -q and
2146	the --noprompt options do not exist.
2147	40. C. The ssh-keygen command will be used for this purpose, and the -t option specifies the
2148	type of key to generate. There are no key-related generation options for the ssh command.
2149	41. B. Lines can be commented out of /etc/inetd.conf with a pound sign or hash mark (#).
2150	After making changes to /etc/inetd.conf, the service should be restarted.
2151	42. A. The -L option to usermod can be used to lock an account. The lowercase version, -l, is
2152	used to change a username. The other commands do not exist.43. B. The pubring.gpg file, found in ~/.gnupg/, contains the public keyring.
2153	44. C. The .gpg-v21-migrated file, when present, indicates that gpg version 2.1 or later is in
2154	use and that the files have been migrated for that version or a later one.
2155	45. D. The find command will be used for this purpose, and the -perm option is needed,
2156	specifically as the 2000 permission to indicate setgid. Note the use of / to indicate that the
2157	entire server will be searched. The grep command shown cannot be used for this purpose
2158	because it looks for the presence of the string 'setgid' within files located in the current
2159	directory only.
2160	46. C. The update-rc.d command creates symbolic links from a service file in /etc/init.d/
2161	to the appropriate locations in /etc/rc.d/* for each runlevel. The other commands shown
2162	are not valid.
2163	47. A. Single-user mode is typically runlevel 1. In runlevel 1, no network services are started.
2164	Runlevel 2 has networking but typically not services. Runlevel 5 is full multiuser with
2165	networking, and runlevel 6 is reboot.
2166	48. C. The - option is the typical option passed to su for login. There is no -u or -U option,
2167	and the -login option does not exist. There is a --login option with two dashes, but that
2168	is not what’s shown.
2169	49. A. The netstat command is used for this purpose, and the -a option displays all
2170	sockets, listening and nonlistening. Note that it’s frequently helpful to add the -n option,
2171	or combine them as in netstat –an, in order to prevent name lookup. Doing so can
2172	significantly improve the performance of the command.
2173	50. C. This solution will require a way to filter out the bind user; therefore, options that grep
2174	for bind or specify bind as the user are incorrect. However, the lsof command allows for
2175	negation with the caret (^) character. Therefore, listing all files except bind requires the
2176	syntax shown.
2177	51. B. The -R option requires an attempt at name resolution be performed. The -n option does
2178	the opposite; it disables name resolution. There is no -b or -a option.
2179	52. C. The PARANOID wildcard specifies that the hostname and IP must match. The ALL
2180	keyword is also a valid wildcard in TCPWrappers for use in both /etc/hosts.allow and
2181	/etc/hosts.deny.
2182	53. A. The PermitRootLogin directive, set to yes or no, determines whether the root user can
2183	log in directly. The other options shown are not valid.
2184	54. B. The nmap command will be used for this purpose, and the -sT option performs a TCP
2185	connect to the specified host or network. The other commands are not valid.
2186	55. C. The -X option enables X11 application forwarding through an SSH connection.
2187	The -A option is used for authentication agent forwarding, and -F indicates a per-user
2188	configuration file. There is no -X11 option.56. B. The --output option is used with --encrypt to send the output to a specified file. The
2189	other options shown are not valid for gpg.
2190	57. B. The ssh-add command adds keys to ssh-agent. The other commands shown are not
2191	valid.
2192	58. B. The -x option sets the maximum password age until the password needs to be changed
2193	again. The -l option locks the account, and the other options do not exist.
2194	59. A. The -l option sets the maximum amount of memory that can be locked. The -t option
2195	sets the maximum CPU time, and the -x and -b options do not exist.
2196	60. B. The command shown to display the password file and pipe the output into cut will
2197	display the usernames from the password file, /etc/passwd. The /etc/shadow file would
2198	also produce the same output.
2199	61. B. The access_times configuration item sets the times in which access is allowed. The
2200	other configuration options shown are not valid.
2201	62. A. The .socket file extension is used for interprocess communication, network sockets,
2202	and first-in, first-out (FIFO) queues controlled by systemd. For more information, see
2203	systemd.socket.
2204	63. C. The -N option provides the “new” passphrase, and when generating a key, it can be
2205	used to generate an empty password. The -p and -P options both work with passwords but
2206	would do so on an existing key. The -d option does not exist for ssh-keygen.
2207	64. A. The MD5 algorithm has been used if the password in /etc/shadow begins with $1$. Of
2208	the other options, shadowed passwords beginning with $2a$ or $2y$ would indicate the
2209	Blowfish algorithm. There is no RIN or PIK algorithm for shadow passwords.
2210	65. B. The --detach-sig option creates a detached signature file so that the original file
2211	remains unchanged. Both the original file and detached signature file are needed in order to
2212	verify the signature. The other options do not exist.
2213	66. C. The server host key provides a means by which clients can verify that the server host key
2214	has not changed.
2215	67. B. The IdentityFile option specifies the key that will be used to connect to the host. The
2216	other options do not exist for client configurations in SSH.
2217	68. C. The gpg-agent command is a daemon process to manage private keys. The gpg
2218	program and other GnuPG-related utilities use gpg-agent. The other options shown for
2219	this question are not valid.
2220	69. D. The sudoedit editor, part of the sudo package, can be used for the purpose described.
2221	Of the other commands, only nano is a real command, but it would also present the same
2222	possibility of shell escapes as vim would in this scenario. While there may be ways to
2223	prevent a shell escaping with both vim and nano, sudoedit is typically the preferred option.70. A. The -l option changes the login name for a connection with ssh. Among the other
2224	options, only -a and -m exist and are not used for the purpose described.
2225	71. A. The -l option for usermod changes the username. It is worth noting that the user’s
2226	home directory and mail spool file do not change and would need to manually be changed
2227	following the usermod command. The other options are not used for the purpose described.
2228	72. C. The send-keys option followed by the name of the key sends the key to the key server
2229	specified by the key server option. This is a typical scenario for sending a locally generated
2230	public key to a public server for others to use. The other options do not exist.
2231	73. D. The % is used to denote a group within /etc/sudoers and provides an excellent way to
2232	facilitate an administrative privileged group.
2233	74. D. The fsize option is used within the limits.conf file to control the maximum size of a
2234	file that can be created by a user for whom the limit applies.
2235	75. B. The ServerAliveCountMax option is used to set the number of keepalive messages
2236	that can be sent by the client but not responded to before the client will terminate the
2237	connection.
2238	76. C. The /etc/nologin file prevents login when present and can also contain a message that
2239	is displayed to users when attempting to login.
2240	77. A. The -t option specifies the lifetime for the key and is usually given in seconds but can
2241	also be given in minutes, hours, days, and weeks with qualifiers. The other options shown
2242	do not fulfill the scenario described.
2243	78. A. The -R option sets up a remote forward so that remote users can also connect to the
2244	tunnel being set up. The other options are not valid for the remote forwarding scenario.
2245	79. B. The -W option sets the number of days to warn a user before their password expires. The
2246	other options do not exist for chage.
2247	80. B. The /etc/shadow- file contains the state of the shadow file before the last change and
2248	would likely be the first place to begin recovery. The next would likely be a backup, though
2249	/var/backups/ does not hold backups unless manually created.
2250	81. B. Integration with the libwrap library is an indicator that a given service or daemon will
2251	be able to utilize TCP wrappers for access control.
2252	82. A. The User_Alias option enables specification of a group of users for use elsewhere
2253	within the sudoers file.
2254	83. A. Setting -P0 will allow no ping requests to precede the scan and is useful for the scenario
2255	described. There is an -s option, but it is not used for this purpose. The other options are
2256	not valid.
2257	84. C. The UserKnownHostsFile configuration option enables specification of the location and
2258	filename for the known hosts file for users.85. C. The -t argument sets the type of key to generate, and dsa creates a key with the dsa
2259	algorithm. Other types includes rsa and ecdsa. The files are normally placed in /etc/ssh
2260	and assigned names such as ssh_host_[algorithm]_key and ssh_host_[algorithm]_
2261	key.pub, where [algorithm] is one of rsa, dsa, ecdsa, or ed25519.
2262	86. C. The -q option prints the users who are logged in along with a count of those users. The
2263	-l option prints the login processes, the -t option prints the last system time change, and
2264	the -e option does not exist.
2265	87. B. The -u option unlocks an account while setting the password. The -l option locks the
2266	account, and the -t and -r options do not exist for the passwd command.
2267	88. C. The maxlogins option is used to control the number of times that a user can log in. The
2268	only other limit-related option shown is maxsyslogins, which sets the maximum number
2269	of logins for the entire system.
2270	1. B. The /proc filesystem stores information about running processes on the system.
2271	The /etc filesystem is used for configuration information, and /dev is used for device
2272	information. The /environment filesystem does not exist on a default Linux system.
2273	2. C. The /etc/modprobe.d directory contains information related to the modprobe
2274	configuration. This can be overridden with the -C option on the command line.
2275	3. A. The -g option to wall sends the input to the specified group. Answer B will send the
2276	output to all users, whereas answers C and D will not work.
2277	4. B. The -e option to dmesg displays the time in a localtime and the delta in a format that is
2278	typically easier to work with. The -rel option does not exist. The -f option specifies the
2279	logging facility, and -t does not display time at all.
2280	5. B. The init process is typically associated with the initial process ID of 1 to indicate
2281	that it is the process from which others are spawned. Killing PID 1 will typically and
2282	immediately halt the system.
2283	6. C. The lspci command shows the PCI devices in the system, and the -k option shows the
2284	kernel driver being used by the given device. The lsusb command will not accomplish the
2285	task requested and the ls command with -pci will not display the correct information.
2286	There is no showpci command.
2287	7. C. The --no-wall option will cause telinit to not send a wall command to logged-in
2288	users about the state change. The other options listed in this question do not exist.
2289	8. A. The class/net hierarchy within /sys contains information on the network
2290	configuration for the computer. It is a symlink to the devices hierarchy, where the device
2291	will be listed by its address rather than the logical eth0 name.9. B. The SIGTERM signal is the default signal sent with the systemctl kill command.
2292	10. D. A logical location to begin troubleshooting is within the system BIOS to ensure that the
2293	drive is being detected by the computer.
2294	11. C. The dbus-monitor program, which requires an X display, can be used to monitor dbus.
2295	The other programs and options listed for this question do not exist.
2296	12. A. The udevd service is called systemd-udevd.service within a systemd environment.
2297	13. A. The system can be scheduled to shut down at a certain time, and that time should be
2298	entered in 24-hour format, as shown in the answer.
2299	14. C. The -s option changes the signal to be sent from its default of SIGTERM. The new signal
2300	must be one of the main signal types, such as SIGINT or SIGSTOP.
2301	15. D. The list-unit-files command will show the files available, whereas
2302	--type=service will limit those files to the services, in the same way that
2303	chkconfig --list returns a list of services.
2304	16. A. The -C option sets the location of the cache to be updated instead of the default
2305	/etc/ld.so.cache. The lowercase option, -c, changes the format of the cache, whereas -v
2306	sets verbose mode. The --f option does not exist.
2307	17. C. The -P option to dpkg will purge a package from the system, including the
2308	configuration files associated with the package. The apt-cache clean command cleans the
2309	package cache but not an individual package, and the apt-get remove command removes
2310	a package but not the associated configuration files.
2311	18. C. The deb-src prefix is used to indicate that a given repository contains source packages.
2312	The deb prefix in option A would indicate normal packages. The other options are not
2313	valid.
2314	19. B. The -U option is used to upgrade a package. Adding -v for verbose and -h for hash
2315	marks will print additional information and progress, as requested by the problem.
2316	20. A. The -y or --assumeyes option will do what it says: Assume that you will answer “yes”
2317	and therefore not prompt. The other options do not exist.
2318	21. A. The exclude option within /etc/yum.conf is a space-separated list of packages that
2319	accepts wildcards and is a list of packages that cannot be installed or upgraded. The other
2320	options listed in this question do not exist.
2321	22. C. The ldconfig command is used to work with the library cache, and the -p option
2322	prints the directories and libraries in the cache. The -C option tells ldconfig to use a
2323	different cache. The ldd command prints the library dependencies for a given command,
2324	but the options given don’t exist for ldd.
2325	23. D. The baseurl option is used to set the URL and must be fully qualified, meaning that it
2326	must include the protocol, such as http:// or file://.24. B. The apt-cache dump command will display a listing of the available packages and their
2327	respective dependencies. The other commands and options listed in this question do not
2328	exist.
2329	25. A. The /boot directory almost certainly exists but has not been partitioned into its own
2330	space. The /boot partition would not be hidden from lsblk if it was indeed a separate
2331	partition.
2332	26. B. The /var/cache hierarchy contains cached data for both package management tools—
2333	in the case of yum, in /var/cache/yum, and in the case of a Debian-based system, in /var/
2334	cache/apt.
2335	27. A. The master boot record (MBR) is the typical location for the boot loader to be stored on
2336	a BIOS-based system.
2337	28. D. The / filesystem is the root filesystem. If separate partitions have not been created, the
2338	/ filesystem will be the beginning of the hierarchy and will contain all other directories in
2339	the same partition.
2340	29. A. The --output option configures the location for output of the command instead of
2341	STDOUT.
2342	30. A. The dd command is used for this purpose, and for this case it takes an input file with
2343	the if option and an output destination with the of option. The bs option signals that the
2344	block size for writing should be 1 megabyte.
2345	31. D. The history command displays history from the current session and can be used for
2346	the purpose described. The .bash_history file is written on session close, by default.
2347	32. C. The --boot-directory option will install the boot images into the directory specified.
2348	This might be helpful for nonstandard installs or at times when you need to mount the boot
2349	partition separately. The other options listed in this question do not exist.
2350	33. A. The update-grub command should be executed in order to make changes take effect
2351	in the menu and when changes have been made to the GRUB configuration. The other
2352	commands listed in this question do not exist.
2353	34. B. The export command is used for this purpose and accepts a name=value pair, as shown
2354	in the answer. The other commands are not valid with the exception of the echo command,
2355	which will simply echo the argument to the console.
2356	35. C. The HISTFILESIZE option configures the number of commands to keep in the history
2357	file. The other variables are not valid within Bash.
2358	36. D. The -b option configures the body numbering format for nl, which by default will not
2359	number blank lines. The a format option will number all lines, including blanks. The -a
2360	option is not valid for the nl command, and the -n option configures the numbering format
2361	and would require an additional argument in order to be valid.
2362	37. D. The od command is used to create octal output. The cat command will show the file as
2363	it exists on disk. The other two commands are not valid.38. A. The pr command formats text for printing, including the date and page numbers at the
2364	top of each page. Adding the -d option causes the output to be double-spaced. The cat
2365	command will display output but not paginated in such a way. The other two commands
2366	are not valid.
2367	39. A. The -n option is used to change the number of lines. Adding the +N after the -n option
2368	begins the tail process at the Nth line within the file.
2369	40. C. The -i option causes the unique test to be done while ignoring the case of the element
2370	to be matched.
2371	41. C. The awk command shown can be used for this purpose. The -F option sets the field
2372	separator, and the OFS option sets the output field separator.
2373	42. C. The -a option is equivalent to the -d and -R options, which preserve links and copy
2374	recursively, respectively. The -b option creates a backup, and -f forces the copy.
2375	43. A. When in command mode, typing a number followed by an uppercase G will immediately
2376	move the cursor to that line number. The /23 option will search for the number 23 in the
2377	file. The i23 option will insert the number 23, and finally ZZ will exit Vi.
2378	44. A. The -d option changes the update interval and can be helpful on a busy system where
2379	top may be affecting performance. The -n option sets the number of iterations to run.
2380	There is no -t or -f option for top.
2381	45. B. The ps -e command is used to display all processes, and the -o option configures the
2382	columns to display.
2383	46. A. The grep command will be used for this purpose. Note the difference between grep -r
2384	and grep -ri. The question did not ask for case insensitivity, and therefore the use of -i in
2385	option B makes it incorrect.
2386	47. B. The find command will be used for this purpose. Setting the directory from which to
2387	begin the find is required, along with the expression, which in this case, are files beginning
2388	with DB.
2389	48. B. Load average information is gathered from /proc/loadavg, whereas uptime
2390	information is stored on /proc/uptime.
2391	49. D. Interactive repair is the default, so no option is required. The -f option forces the
2392	operation, and -y and -a are both variations of noninteractive repair.
2393	50. D. The /etc/mtab file is updated dynamically as filesystems are mounted and unmounted.
2394	The /etc/fstab file is not dynamically updated.
2395	51. B. The -B option changes the format, and T sets the scale to terabytes. The -T option alone
2396	prints the filesystem type. The other options do not exist.
2397	52. A. The e2image program can be used to create an image of metadata that can help with
2398	drive recovery. The resulting image file can be used with programs like dumpe2fs and
2399	debugfs.53. C. The -c option checks for bad blocks. The -b option sets the block size. There is no -a or
2400	-d option.
2401	54. B. The chown command is used for this purpose and can be used to set both the user and
2402	group for ownership.
2403	55. A. The ssh-keyscan command can be used for the purpose described and can help with
2404	virtual machine deployment by obtaining the SSH host key and adding it to the known_
2405	hosts file.
2406	56. C. The GRUB_RECORDFAIL_TIMEOUT option is used to configure the behavior of the system
2407	in the event of a failed boot. Setting the value to -1 will display the GRUB menu and not
2408	continue booting. Setting the value to 0 will cause the menu to not display. Setting to a
2409	value greater than or equal to 1 will cause the menu to display for that many seconds.
2410	57. A. The -s option displays a summary, and -h displays it in a human-readable format.
2411	58. D. The -L option tells find to follow symlinks. The -H and -P options are both variations
2412	to tell find not to follow symlinks, and the -S option does not exist.
2413	59. A. The -a option appends to the file rather than overwriting when using tee. The other
2414	options do not fulfill the needs of the problem statement.
2415	60. C. The /etc directory and its subdirectories typically contain configuration files that
2416	would be necessary in order to re-create the system in a restoration scenario. The /var
2417	directory usually contains variable information, whereas /opt may be used for several
2418	other purposes. The /bin directory contains binaries that can usually be reinstalled.
2419	1. A. The /etc/hosts.deny file is part of TCP wrappers along with /etc/hosts.allow.
2420	Both provide a basic mechanism for configuration of access from remote hosts to network
2421	services.
2422	2. C. The alias command uses the alias name followed by an equal sign followed by the
2423	command to be aliased. In this case, because the command to be aliased contains spaces, it
2424	needs to be contained in quotation marks.
2425	3. C. Shell scripting syntax uses the format shown, with square brackets around the condition
2426	to the tested and double-equal signs for a string test. Variables are preceded by a dollar sign
2427	as shown.
2428	4. A. The export command is necessary so that any variables that are manually defined in
2429	your current session become available to child processes. The source command executes
2430	the file and can be used for the purpose described but requires an additional argument. The
2431	let and def commands are not valid.5. C. The source command is the functional equivalent of a single dot (.). The set command
2432	exists but is not used for this purpose. The other commands are not valid.
2433	6. A. The syntax for setting the PATH separates the new path with a colon, as shown in the
2434	correct option. A primary difference between the correct and incorrect options for this
2435	question was in how the actual specified path was shown.
2436	7. A. The correct syntax is as shown. Note that a semicolon is required when the commands
2437	are included on one line, as displayed in the answer.
2438	8. C. The mail command with -s for the subject is necessary, followed by the email address
2439	for the mail. Then, input is redirected to the mail command using /etc/hostname.
2440	9. C. The /etc/skel directory contains files that are a skeleton of a user’s home directory
2441	when their account is created. The other directories listed do not exist by default.
2442	10. D. The Universal Access section, which can be found by typing Universal Access from
2443	within an Ubuntu GUI interface, enables configuration of accessibility options.
2444	11. B. The kbdrate command is used for the purpose described and can help with accessibility.
2445	The other commands shown are not valid.
2446	12. A. The DISPLAY variable controls the destination and screen for displaying GUI
2447	applications. Setting this variable facilitates forwarding of X applications over ssh.
2448	13. B. The xhost command is used to control who can make connections for both users and
2449	hosts to a given X server. The other commands are not valid.
2450	14. B. The -f option sets the days between expiration and disabled for an account. The -g
2451	option is used to set the group ID, whereas -e is used to set the overall expiration date.
2452	15. A. The getent command can be used for the purpose described and will display the aliases
2453	on the server by examining the aliases database. The other commands are not valid and,
2454	in the case of the mail command shown, will simply attempt to send mail to an address
2455	known as aliases.
2456	16. C. The ALL: ALL syntax will cause all hosts to be denied. This means that you must
2457	explicitly authorize hosts and networks using /etc/hosts.allow.
2458	17. B. The current at jobs for all users are shown when atq is executed as superuser.
2459	18. C. The -r option to the crontab command removes all cron entries for a given user. The
2460	-l option lists cron jobs, whereas the -e option edits the crontab. There is no -d option.
2461	19. A. The -u option specifies the user. The -l option lists the cron jobs and -e edits them.
2462	There is no -d or -m option.
2463	20. A. The userdel command, given no other options, does not delete the home directory.
2464	When given the -r option, the command will delete the home directory and mail spool file.
2465	There is no -h or -p option for the userdel command.21. D. The -gid option is used to specify group ownership for the find command. The -group
2466	option does exist, but since the question specified that the group had already been deleted,
2467	the gid must be used instead. There is a -name option, but it searches by name and not
2468	group ID.
2469	22. B. The groupmod command will be used for this purpose, and the -n option followed by
2470	the new group name is used to change the name. There is no groupchg command.
2471	23. D. The journalctl command is used to view and parse log file entries on systemd-based
2472	systems that maintain logs in a special format. The logger command can be used to create
2473	log entries, and the other commands shown do not exist.
2474	24. A. The -o option followed by either 1 or 2 enables ntpdate compatibility with older
2475	NTP servers. The default, when no -o option is specified, is version 3. The -v option tells
2476	ntpdate to be verbose, whereas the -e option sets the authentication timeout.
2477	25. D. The /var/log/journal directory is used to store journal log files for systemd-based
2478	systems. The other directories do not exist by default.
2479	26. C. The -m option sets the mail program to use when mailing logs. It is set to /usr/
2480	bin/mail -s by default. There is no -o option, and -v is verbose. The -s option to the
2481	logrotate command sets the state file to use.
2482	27. A. The -u option configures the output to UTC regardless of the time zone. The -s option
2483	sets the time, and there is no -v or -t option.
2484	28. D. The lprm command is used to remove print jobs on a system that uses the lp system for
2485	printing. There is no lpdel or rmprint command. There is an rm command, but it’s not
2486	used for working with print queues.
2487	29. D. The 255.255.254.0 subnet mask is equivalent to /23. The 255.255.255.0 subnet mask is
2488	/24. The subnet mask 255.255.255.255 is /32, and 255.255.0.0 is /16.
2489	30. A. The /etc/hosts file will be examined first, and then a Domain Name System (DNS)
2490	query will be sent based on the configuration shown.
2491	31. D. Standard LDAP traffic is TCP port 389 on the server. TCP port 25 is SMTP, 443 is
2492	HTTPS, and 143 is IMAP.
2493	32. C. The -l option to ssh changes the username sent for authentication. This can be useful
2494	for scripting scenarios where the @ notation cannot be used. The -v option is verbose mode,
2495	and -i is the identity file to use. There is no -u option.
2496	33. D. The -n option disables name resolution for addresses involved in the ping request/reply.
2497	The -D option returns a time stamp, whereas -d sets the SO_DEBUG option. Finally, -f is a
2498	flood ping.
2499	34. A. The ifconfig command shows various statistics about the interfaces on a Linux
2500	system, including whether the interface is up or down, its packets and bytes, queue length,
2501	and other information. The other commands listed do not exist.
2502	35. C. The -C option shows the SOA for each of the DNS name servers listed as authoritative
2503	for the domain. The -a option sends an ANY query, whereas -N sets the number of dots for
2504	the domain to be considered absolute. There is no -n option.
2505	36. A. The entire 127.0.0.0/8 range is available for local host addresses. Therefore, an
2506	answer would need to be in this range. The proper format for /etc/hosts is IP address
2507	followed by name, followed by optional aliases, which makes option A correct.
2508	37. C. The --ignore-errors option tells ifup to continue even if there are otherwise fatal
2509	errors. The -h option outputs help. There is no -C or --continue option.
2510	38. C. The -u option unlocks an account that was locked using the -l option. The -w option
2511	sets the warn days, and -S prints the status.
2512	39. C. When connecting to an alternate port, you can use the -p option to set the port or use a
2513	colon to separate the host from the port.
2514	40. B. The mailto configuration option sets the destination for emails related to sudo. The
2515	other options listed are not valid for sudo.
2516	41. B. The who command displays who is currently logged in and the date and time they logged
2517	in. The whois command displays information about domains. The other commands are not
2518	valid.
2519	42. C. Port 123 is used for NTP communication by default. Port 161 is SNMP, 139 is
2520	NetBIOS, and 194 is IRC.
2521	43. D. A UDP scan can be initiated with -sU. A scan of -sT is a normal TCP scan, and -sS is a
2522	SYN scan. There is no -sP option.
2523	44. B. The +D option is used to search an entire directory tree for files that are open
2524	by processes. The -d option does essentially the same thing but does not go into
2525	subdirectories. The -f option is typically used in combination with other options to control
2526	path name interpretation. The -i option lists files or processes with open ports.
2527	45. C. The -r option causes the ip command to attempt to resolve IP addresses. The -f option
2528	specifies the protocol family. There is no -n or -a option to the ip command.
2529	46. A. The ss command will be used, and when given the -o option, timer information is
2530	displayed. The netstat -rn command shows route information but not sockets or timing,
2531	and ping -f is a flood ping and not related. The ls -l command displays files in a long
2532	listing format.
2533	47. C. All of the addresses shown are in private ranges. The only one with the correct netmask
2534	is 255.255.255.0, which is equivalent to 24 masked bits.
2535	48. C. The !H sequence indicates host unreachable. Network unreachable is !N.
2536	49. D. There is no port for ICMP. The protocol itself does not use ports.50. B. The /etc/services file contains the port number to name translation for a given server.
2537	The file contains well-known ports and can be customized on a per-server basis.
2538	51. A. The command shown launches speech output for Orca. The other commands contain
2539	options that are invalid and thus will not work.
2540	52. A. The configuration files can be found in the /etc/lightdm hierarchy or in /usr/share/
2541	lightdm. The other directory locations do not exist by default.
2542	53. D. The xwininfo command is used to gather information about windows. The other
2543	commands shown are not valid.
2544	54. A. The tzconfig command can be used on a Debian system to set the time zone. The other
2545	commands listed do not exist.
2546	55. C. The locale command will be used for this purpose, and the -m option displays the
2547	available character maps. There is no charmap or mapinfo command.
2548	56. B. Time zone information is found within the /usr/share/zoneinfo hierarchy. The other
2549	directories listed do not typically exist by default.
2550	57. A. The default location on a Red Hat system is /var/lib/ntp/drift. The other locations
2551	shown do not exist by default. Within /etc/ntpd.conf, the location of the drift file can be
2552	changed with the driftfile option.
2553	58. C. The <<< character combination reads input from STDIN or standard input and uses it
2554	as the body of the message for the mail command.
2555	59. C. The groupdel command is used to remove a group from a system. No members of the
2556	group can remain or the command will fail.
2557	60. C. The lpr syslog facility sends messages from the lp subsystem to syslog. The auth
2558	facility is used for security-related messages. The other listed options are not syslog
2559	facilities.