Linux has become one of the fastest growing operating systems used in server environments. Most companies utilize some type of Linux system within their infrastructure, and Linux is one of the major players in the cloud computing world. The ability to build and manage Linux systems is a skill that many companies are now looking for. The more you know about Linux, the more marketable you’ll become in today’s computer industry.

The purpose of this book is to provide you with the knowledge and skills you need to succeed in the Linux world.

Exercise

An exercise is a procedure that you should try on your own computer to help you learn about the material in the chapter. Don’t limit yourself to the procedures described in the exercises, though. Try other commands and procedures to truly learn about Linux.

The Exam Objectives

The exam objectives define the topics you can expect to find in the CompTIA Linux+ exam. The exam developers have determined that these topics are relevant to the skills necessary to become a competent Linux administrator and have based the exam questions on your ability to demonstrate your knowledge in these topics. The official CompTIA Linux+ XK0-004 exam topics are listed here, along with references to where you can find them covered in the book.

Answers to Assessment Test

1. C. The Samba software package allows Linux servers and clients to communicate with Windows and Mac clients or servers using the Microsoft SMB protocol, so option C is correct. The Postfix software package provides email service for Linux servers, not Windows services, so option A is incorrect. The Apache package is a web server; it doesn’t allow Linux servers to share folders with Windows and Mac clients, so option B is incorrect. The Kerberos package provides authentication services; it does not allow Linux servers to share folders, so option D is incorrect. The Docker package provides container services for deploying applications on a Linux server; it does not allow the Linux server to share folders with Windows or Mac clients, so option E is incorrect.
2. E. The Docker package provides a method for developers to capture the entire development environment for an application and deploy it into a production environment as a container, so option E is correct. The Postfix package provides email services for a Linux server; it doesn’t deploy applications, so option A is incorrect. The Apache package provides web server services for a Linux server; it doesn’t deploy application environments, so option B is incorrect. The Samba package allows a Linux server to interact in a Windows network with Windows clients and servers; it does not provide an environment for deploying applications, so option C is incorrect. The Kerberos package provides authentication services for Linux servers; it doesn’t deploy applications, so option D is incorrect.
3. D. The cat -n File.txt command will display the File.txt text file along with line numbers. Therefore, option D is correct. The command in option A will simply display the File.txt file. Thus, option A is a wrong answer. To see any special hidden characters within the File.txt file, you would need to enter the command cat -A File.txt. Therefore, option B is an incorrect choice. End-of-line characters need a different cat command option, such as the -E switch. Therefore, option C is a wrong choice. The cat command does not have a switch that will allow a text file’s contents to be displayed in reverse order. Thus, option E is an incorrect choice.
4. B, C, D. The sed, awk, and gawk utilities are all stream editors. Therefore, options B, C, and D are correct. Both vim and nano are considered to be text editors. Therefore, options A and E are incorrect choices.
5. A. GRUB2 identifies the hard drives starting at 0, but the partitions start at 1, so the first partition on the first hard drive would be 0,1 and option A is correct. Option B (1,0) defines the second hard drive and an incorrect partition number, so it is incorrect. Option C defines the first partition but the second hard drive, so it is incorrect. Option D defines the first hard drive but an incorrect partition, so it is incorrect. Option E uses the keyword first, which is not recognized by GRUB2, so it is incorrect.
6. C. The fsck program can perform a filesystem check and repair multiple types of filesystems on partitions, so option C is correct. The mount program is used to append a partition to a virtual directory; it can’t correct a partition that contains errors, so option A is incorrect. The unmount command removes a partition from the virtual directory, so option B is incorrect. Option D (the dmesg command) displays boot messages, and option E (the mkinitrd command) creates an initrd RAM disk, so both are incorrect.
7. B. The init program is typically started immediately after the Linux system has traversed the boot process, and it has a process ID (PID) number of 1. Therefore, option B is the correct answer. The Linux kernel has the 0 PID number, and thus, option A is a wrong answer. Options C, D, and E are also incorrect choices.
8. E. The systemctl get-default command will display a systemd system’s default target. Therefore, option E is the correct answer. The grep initdefault /etc/inittab command will extract the default runlevel for a SysV init system. Thus, option A is a wrong answer. The runlevel command will display a SysV init system’s previous and current runlevel. Therefore, option B is an incorrect answer. The systemctl is-enabled command shows whether or not a particular service, whose name is passed as a command argument, is configured to start at system boot. Thus, option C is a wrong choice. Option D is a made-up command and therefore the wrong answer.
9. B. The Cinnamon desktop environment uses the Muffin windows manager. Therefore, option B is the correct answer. Mutter is the windows manager for the GNOME Shell desktop environment, though Muffin did fork from that project. Thus, option A is a wrong answer. Nemo is the file manager for Cinnamon, and therefore, option C is a wrong choice. Dolphin is the file manager for the KDE Plasma desktop environment. Thus, option D is a wrong choice. LightDM is the display manager for Cinnamon, and therefore, option E is also an incorrect choice.
10. E. The Ctrl+Alt+Backspace will kill your X11 session and then restart it, putting you at the login screen (display manager.) Therefore, option E is the correct answer. The Ctrl+C combination sends an interrupt signal but does not restart an X11 session. Thus, option A is a wrong answer. The Ctrl+Z keystroke combination sends a stop signal, but it will not restart the X11 session. Therefore, option B is also an incorrect answer. The Ctrl+Q combination will release a terminal that has been paused by Ctrl+S. However, it does not restart an X11 session, so it too is a wrong choice. The Ctrl+Alt+Delete keystroke combination can be set to do a number of tasks, depending upon your desktop environment. In some cases, it brings up a shutdown, logout, or reboot menu. However, it does not restart the X11 session, so option D is an incorrect choice.
11. C. Both Debian-based and Red Hat–based Linux distributions store the time zone template files in the /usr/share/zoneinfo folder, so option C is correct. The /etc/timezone and /etc/localtime files contain the current time zone file for Debian- and Red Hat–based systems, not the time zone template files, so options A and B are incorrect. The /usr/share/timezone and /usr/share/localtime folders don’t exist in either Debian-based or Red Hat–based Linux distributions, so options D and E are also incorrect.
12. A. The timedatectl program is part of the systemd package and allows you to both view and change the current time, date, and time zone for the Linux system, so option A is correct. The localectl program is also part of the systemd package, but it handles localization information and not time and date information, so option B is incorrect. The date command allows you to view and change the time and date but not the time zone setting, so option C is incorrect. The time command displays the elapsed CPU time used by an application, not the current time, date, and time zone, so option D is incorrect. The locale command allows you to view the localization settings for the Linux system, not the time, date, or time zone, so option E is also incorrect.
13. A, D. The /etc/default/useradd file and /etc/login.defs file are files that contain user account creation directives used by the useradd command. Therefore, options A and D are the correct answers. Option B’s /etc/useradd file is a made-up file name, and thus option B is a wrong choice. The /etc/adduser.conf file is only on Linux distributions that use the adduser utility to create accounts. Thus, option C is an incorrect answer. The /etc/login.def file is a made-up file name, and thus option E is also an incorrect choice.
14. E. The repquota -a command will display the various quotas on all your filesystems employing quota limits. Therefore, option E is the correct answer. The edquota -t command will edit quota grace periods for the system. Therefore, option A is a wrong answer. The quotaon -a command will automatically turn on quotas for all mounted non-NFS filesystems in the /etc/fstab file, but it does not display filesystems’ quotas. Thus, option B is an incorrect choice. The quotacheck utility creates either the aquota.group file, if the -cg options are used, or the aquota.user file, if the -cu switches are used, or both files if -cug is employed. However, it does nothing for displaying filesystems’ quotas. Thus, options C and D are incorrect answers.
15. A. Option A is the correct answer because Linux uses the /dev/sdxx format for SCSI and SATA raw devices. The device is represented by a letter, starting with a, and the partition is represented by a number, starting at 1. So /dev/sdb1 references the first partition on the second SCSI or SATA device. Option B would be referenced by the /dev/sda2 file, so it is incorrect. Option C would be referenced by the /dev/hdb1 file, so it is incorrect. Option D would be referenced by /dev/hda2, so option D is incorrect, and option E would be referenced by /dev/sdb2, so it is incorrect.
16. C. The lvcreate program creates a logical volume from multiple partitions that you can use as a single logical device to build a file system and mount it to the virtual directory, so option C is correct. The mkfs program creates a filesystem on a partition, but doesn’t create a logical volume, so option A is incorrect. The pvcreate program identifies a physical volume from a partition but doesn’t create the logical volume, so option B is incorrect. The fdisk program creates and modifies physical partitions, not logical volumes, so option D is incorrect. The vgcreate program creates a volume group for grouping physical partitions, but doesn’t create the logical volume, so option E is incorrect.
17. B, C, D, E. The zip, tar, rsync, and dd utilities all can be used to create data backups. Therefore, options B, C, D, and E are correct answers. The gzip utility can be used after a backup is created or employed through tar options to compress a backup, so option A is the only wrong choice.
18. B, E. Both the md5sum and sha512sum utilities produce hashes on files, which can be compared to determine if file corruption occurred, such as when transferring a file over the network. Therefore, options B and E are the correct answers. The utilities mentioned in options A, C, and D will allow you to securely transfer files but not check a file’s integrity. Therefore, options A, C, and D are incorrect choices.
19. A. The dpkg program is used for installing and removing Debian-based packages that use the .deb file format, so option A is correct. The tar program is used for creating and extracting tape archive formatted files that use the .tar file extension, so option B is incorrect. The gcc program is used for compiling source code into executable programs, so option C is incorrect. The rpm program is used for installing and removing Red Hat–based packages that use the .rpm file format, so option D is incorrect. The gzip program compresses files and adds the .gz file extension to them, so option E is incorrect.
20. D. The rpm program is used for installing and removing Red Hat–based packages that use the .rpm file format, so option D is correct. The dpkg program is used for installing and removing Debian-based packages that use the .deb file format, so option A is incorrect. The tar program is used for creating and extracting tape archive formatted files that use the .tar file extension, so option B is incorrect. The gcc program is used for compiling source code into executable programs, so option C is incorrect. The gzip program compresses files and adds the .gz file extension to them, so option E is incorrect.
21. B. The /proc/modules file has the same information that is displayed by the lsmod utility (though the lsmod utility formats it much nicer). Therefore, option B is the correct answer. The modinfo utility provides detailed module data, while lsmod only shows brief information. Thus, option A is a wrong answer. The /etc/modules.conf file is a kernel module configuration file, and it does not provide the same information as the lsmod utility. Therefore, option C is also an incorrect answer. The insmod command is used to dynamically load kernel modules, and thus it is a wrong answer. The /run/modprobe.d/*.conf files are kernel module configuration files, and they do not provide the same information as the lsmod utility. Therefore, option E is also an incorrect choice.
22. E. The modprobe utility along with its -r switch is the utility to employ for removing (unloading) a kernel module along with any of its dependencies. Therefore, option E is the correct answer. The rmmod utility will remove a kernel module but not any of its dependencies. Thus, option A is a wrong answer. The modinfo command does not unload kernel modules but instead displays detailed information concerning a specified module. Therefore, option B is an incorrect choice. The cut utility is used to filter text files and display the filtered text to STDOUT. It is not involved in kernel module removal, and thus option C is a wrong choice. The depmod utility is used to create a list of modules and their dependencies. But it is not used to remove modules. Therefore, option D is an incorrect choice.
23. C. The sticky bit assigned to a directory restricts all of the files in that directory so that only the file owner can delete the file, even if a user account is in the group that has write permissions, so option C is correct. The SUID bit allows a standard user to run an application with the file owner permissions but doesn’t block users from deleting shared files, so option A is incorrect. The GUID bit is used on a directory to ensure that all files created in the directory have the same group as the directory, but it doesn’t prevent users in that group from deleting files, so option B is incorrect. The Read and Write standard permission bits control access to read to a file or write to a file, but they don’t block users from deleting a file, so options D and E are both incorrect.
24. B. The chown command allows you to set both the owner and group assigned to a file, so option B is correct. The chmod command allows you to change the permissions for the file, but not the owner of the file, so option A is incorrect. The chage command manages password aging for user accounts, not owners of files, so option C is incorrect. The ulimit command allows the administrator to restrict system resources assigned to users but doesn’t assign users to files, so option D is incorrect. The chgrp command allows you to change the group assigned to a file but not the owner, so option E is incorrect.
25. D. The /etc/pam.d/ directory contains the various PAM configuration files. Therefore, option D is the correct answer. The other directory names are made up. Thus, options A, B, C, and E are incorrect answers.
26. B. The settings within the ~/.ssh/config file can be overridden by various ssh utility options provided at the command line. Therefore, option B is the correct answer. The settings in the /etc/ssh/ssh_config file can be overridden by both the settings in the ~/.ssh/config file and the ssh utility’s command-line options, so option A is a wrong answer. The /etc/ssh/sshd_config file is the sshd daemon’s configuration file, and it deals with providing the SSH services, not in setting the configuration for the SSH client. Therefore, both options D and E are incorrect choices.
27. C. The -f option of the tail command displays new additions to a file in real time, so option C is correct. The head and tail commands by themselves just list the existing entries in a file, so options A and B are incorrect. The head command doesn’t support the -f option, so option D is incorrect. The vi editor also only displays existing data in a file and not newly added data, so option E is incorrect.
28. A. The systemd-journald application uses its own binary file format for the journal file and requires the journalctl file to read it, so option A is correct. The syslogd and klogd applications are syslog loggers and not able to read the systemd-journald journal file, so options B and C are incorrect. The systemd-journald application itself only adds event messages to the journal and doesn’t read it, so option D is incorrect. Since the journal file is in binary format, you can’t read it using standard text editor programs, so option E is incorrect.
29. C. The /etc/services file may be used by a firewall, such as UFW, to map a particular service name to its port and protocol. Thus, option C is the correct answer. The file is not used to designate remote services to block or store a firewall’s ACL rules. Therefore, options A and B are wrong answers. The Linux firewall applications do not use the /etc/services file to determine if a port can be accessed or what local services can send out packets. Thus, options D and E are incorrect choices.
30. A, B, C, D. Used by firewalld, UFW, and iptables, netfilter provides code hooks into the Linux kernel for firewall technologies to use in order to implement fully functional firewall capabilities. Therefore, options A, B, C, and D are all correct answers. Unfortunately, netfilter cannot provide firewall services on its own. Thus, option E is the only incorrect choice.
31. A. Bandwidth is a measurement of the maximum data amount that can be transferred between two network points over a period of time. Therefore, option A is the correct answer. Throughput is a measurement of the actual data amount that is transferred between two network points, and thus option B is a wrong answer. Saturation occurs when network traffic exceeds capacity, but it is not a measurement. Thus, option C is an incorrect answer. Latency is the time between a source sending a packet and the packet’s destination receiving it. Therefore, option D is a wrong choice. Routing is the process of forwarding IP packets to the appropriate destination. Thus, option E is also an incorrect answer.
32. E. The vmstat utility provides a lot of memory statistics, including disk I/O specific to swapping. Therefore, option E is the correct answer. The ipcs -m command allows you to see shared memory segments instead of disk I/O specific to swapping. Thus, option A is the wrong answer. The cat /proc/meminfo command displays detailed information concerning a system’s RAM. Therefore, option B is an incorrect answer. The free command shows memory items such as free memory, used memory, and buffer/cache usage. Thus, option C is a wrong choice. The swapon -s command displays swap space elements such as type, name, and priority. Therefore, option D is also an incorrect choice.
33. C. The ps command with the proper options displays the active applications running on the Linux system, so option C is correct. The lsof command displays the files currently open by applications but not all of the running applications, so option A is incorrect. The kill command stops a running application based on its process ID; it doesn’t display all of the running applications, so option B is incorrect. The w command displays all of the current users on the system but not all of the running applications, so option D is incorrect. The nice command allows you to start a new application with a specified priority level, but it doesn’t allow you to display the currently running applications, so option E is incorrect.
34. B, D. The pkill and kill commands allow you to send Linux process signals to running applications, so options B and D are correct. The renice command allows you to change the priority level of a running application but not send process signals to it, so option A is incorrect. The nice command allows you to start an application with a specified priority level but not send process signals to applications that are already running, so option C is incorrect. The pgrep command allows you to display running applications, but it doesn’t send process signals to them, so option E is incorrect.
35. C. The problem is directly related to a missing export command prior to the PS1="My Prompt: " in Annika’s environment file. When this environment variable is exported and when it is set, it will be set in any started subshells. Thus, option C is the correct answer. Since Annika’s environment file exists, the $HOME/.profile file is not used. Thus, option A is a wrong answer. A user prompt can be changed in a subshell, so option B is also an incorrect answer. Changing Annika’s default shell will not fix this issue, so option D is a wrong choice. If Annika changes the last field in her password record to /sbin/false, she will no longer be able to log into the system using her account. Therefore, option E is an incorrect choice.
36. E. In order for a user to list files in a directory, the directory needs to have read (r) set for other permissions if the user is not the directory’s owner or does not belong to the directory’s set group. Therefore, option E is the correct answer. There is no display (d) permission setting, so option A is a wrong answer. The execute (x) permission allows a user to change their present working directory to that directory as long as all the parent directories also have that permission set. Thus, option B is a wrong choice. The write (w) permission allows a user to create files within that directory, so option C is an incorrect answer. There is no list (l) permission setting, so option D is also an incorrect choice.
37. B, D. The Linux kernel uses the /proc and /sys directories to produce dynamic files that contain information about the kernel and system, so options B and D are correct. The /dev folder contains files for communicating with devices, not kernel and system information, so option A is incorrect. The /etc directory contains application configuration files, not files created by the kernel for displaying kernel and system information, so option C is incorrect. The /dev/mapper directory is used for virtual files mapped to physical device files for LVM and LUKS, not kernel information, so option E is incorrect.
38. C. The /etc/X11 directory contains configuration files used by both the X.org and XFree86 applications for controlling the X Windows graphical environment on the Linux system, so option C is correct. The /dev directory contains device files used to send and receive data from devices, not the X Windows configuration files, so option A is incorrect. The kernel uses the /proc and /sys directories to create dynamic files that show kernel and system information, not contain X Windows configuration files, so options B and D are incorrect. The /proc/interrupts file contains information about hardware interrupts currently used by hardware devices on the system, not X Windows configuration files, so option E is incorrect.
39. D. This problem concerns a missing directory. Therefore, to fix it, use super user privileges, if needed, and create the directory via the mkdir command. Thus, option D is the correct answer. The problem does not concern a bad disk sector (and you cannot fix bad disk sectors with the badblocks utility), so options A and B are wrong answers. You would employ the vgchange command for a missing volume in a logical volume but not a missing directory. Therefore, option C is an incorrect answer. While the mountpoint command does allow you to see if a particular directory is a mount point, it does not allow you to create a missing directory. Thus, option E is an incorrect choice as well.
40. A, B, C. Since the problem involves a remote server, you need to investigate the firewall access control lists (ACLs) on both the local and remote systems. Therefore, depending upon their firewall employed, you may use the firewall-cmd, ufw, or iptables command in the troubleshooting process. Thus, options A, B, and C are the correct answers. The getacl and setacl commands deal with file inheritance issues, and therefore options D and E are incorrect choices.
41. C. The for command allows you to iterate through a series of data one by one until the data set is exhausted, so option C is correct. The if and case statements perform a single test on an object to determine if a block of commands should be run; they don’t iterate through data, so options A and B are incorrect. The exit command stops the shell script and exits to the parent shell, so option D is incorrect. The $() command redirects the output of a command to a variable in the shell script, so option E is incorrect.
42. B. The $UID environment variable contains the numeric user ID value of the user account running the shell script, so option B is correct. The $USER environment variable contains the text user name of the user account running the shell script, not the numerical user ID value, so option A is incorrect. The $BASH environment variable contains the path to the executable Bash shell, so option C is incorrect. The $HOME environment variable contains the location of the home directory of the user account running the shell, so option D is incorrect. The $1 positional variable contains the first parameter listed on the command-line command when the shell script was run, so option E is incorrect.
43. C. The ampersand sign (&) tells the shell to run the specified command in background mode in the console session, so option C is correct. The nohup command is used to disconnect the command from the console session, so option A is incorrect. The at command is used to schedule a command to run later, so option B is incorrect. The pipe symbol (|) redirects the output from the command to another command, so option D is incorrect. The greater-than symbol (>) redirects the output from the command to a file, so option E is incorrect.
44. B. The cron table format specifies the times to run the script by minute, hour, day of month, month, and day of week. Thus the format 0 0 1 * * will run the command at 00:00 (midnight) on the first day of the month for every month. That makes option B correct, and options A, C, D, and E incorrect.
45. E. This git package provides utilities to set up Git VCS on a system, so option E is the correct answer. The git-vcs package is made up, so option A is a wrong answer. The GitHub, gitlab, and Bitbucket packages are also made up, but they have similar names as cloud-based remote repositories used with Git (GitHub, GitLab, BitBucket). Therefore, options B, C, and D are also incorrect choices.
46. C. If the -m option with an argument is not tacked onto the git commit command, you are placed into the vim editor to edit the COMMIT_EDITMSG file. Thus, option C is the correct answer. All the other options are made up and therefore incorrect.
47. E. The Microsoft Azure cloud-based virtualization service provides blobs, which are large unstructured data storage that offered over the Internet and can be manipulated with .NET code. Therefore, option E is the correct answer. Amazon Web Services (AWS) and Digital Ocean are both cloud-based virtualization services, but they do not employ storage called blob, so options A and C are wrong answers. KVM is a hypervisor, not a cloud-based virtualization service, so option B is an incorrect answer. GitHub is a cloud-based remote repository used in version control, so option D is also an incorrect choice.
48. C. A software-defined network (SDN) is a networking method for controlling and managing network communications via software that consists of a controller program as well as two APIs. Thus, option C is the correct answer. Thick provisioning and thin provisioning refer to virtual storage configurations, not networking methods, so options A and B are wrong answers. Network address translation (NAT) is a virtualization network adapter configuration, which operates similarly to a NAT router in a network. Therefore, option D is an incorrect answer. A VLAN is a virtual (logical) LAN configuration, and thus, option E is an incorrect choice as well.
49. B, D. Only Kubernetes and Swarm are orchestration systems. Therefore, options B and D are correct answers. Mesos needs Marathon to implement an orchestration engine, so option A is a wrong answer. Splunk can be used as a monitoring tool in an orchestrated environment, but it is not an orchestration system, so option D is also a wrong choice. Amazon Web Services (AWS) is cloud-based virtualization services on which you can use orchestration tools, but it is not an orchestration engine. Thus, option E is also an incorrect choice.
50. A, B, D, E. The concepts listed in options A, B, D, and E are all used in container orchestration. While DevOps benefits from container orchestration and often employs it, it is not used within container orchestration. Thus, option C is an incorrect choice.
51. D. The Software as a Service (SaaS) cloud service type provides full applications, allowing anyone to connect to your application, so option D is correct. The Platform as a Service (PaaS) cloud service type doesn’t include an application; you must provide it yourself, so option A is incorrect. Private, public, and hybrid are all methods of implementing cloud services, not cloud service types, so options B, C, and E are all incorrect.
52. C. The Oracle VirtualBox hypervisor installs on top of a host operating system, making it a Type II hypervisor, so option C is correct. PaaS and SaaS are types of cloud services, not hypervisors, so options A and B are incorrect. A private cloud service is a method for implementing cloud services in an internal network, not a type of hypervisor, so option E is incorrect.
53. C. The /etc/securetty file provides a list of locations from which users can’t log in using the root user account, so option C is correct. The /etc/cron.deny file prevents users from scheduling jobs, not logging in as the root user account, so option A is incorrect. The /etc/hosts.deny file blocks access from remote network hosts; it doesn’t block root access from local terminals or the console, so option B is incorrect. The /etc/login.warn and /etc/motd files contain messages that are displayed at login time; they don’t block users from logging in as the root user account, so options D and E are incorrect.
54. C. The auditd program monitors system activity, including user file and directory access, and logs events based on rules you create. Thus, option C is correct. The chroot utility restricts applications to a specific location in the virtual filesystem but doesn’t log user file and directory access, so option A is incorrect. The LUKS system encrypts disk partitions but doesn’t log user file and directory access, so option B is incorrect. The klist and kinit programs are used for Kerberos user authentication, not logging user file and directory access, so options D and E are both incorrect.
55. D. The cd - command will return your process to its previous directory in the virtual directory system, so option D is the correct answer. The cd and cd ~ commands both return your process to your home directory, which was not necessarily the previous directory. Therefore, options A and C are wrong answers. The exit command causes your process to exit its current shell, not return to the previous directory, so option B is also an incorrect answer. The return command is used in Bash shell scripts to return from a function or return from a sourced script. Thus, option E is also an incorrect choice.
56. B. The -R option used with the cp command allows you to copy a directory’s contents. You can also employ the -r or --recursive options to achieve the same results. Therefore, option B is the correct answer. The -i option will ask before overwriting a preexisting directory but not copy recursively, so option A is a wrong answer. The -v option will provide verbose information for the copy, which is helpful, but does not allow a recursive copy to occur. Thus, option C is also an incorrect answer. The -u option is handy in that it will only allow the cp command to overwrite preexisting files with the same name, if the files being copied are newer. However, it is not used to recursively copy, so option D is also an incorrect answer. The -f option forces a copy to occur and overwrites any preexisting files with the same name but does not force a recursive copy. Thus, option E is an incorrect choice.