Correct Answer: A. Create a custom menu entry for the recovery mode Explanation: By creating a custom menu entry for the recovery mode in the GRUB configuration, you provide an alternative boot option that can be selected if the main OS fails to boot. Option B is incorrect. Setting the default boot entry to the recovery mode will make the system always boot into recovery mode first, which isn‘t ideal for regular use. Option C is incorrect. Disabling the GRUB menu entirely will prevent the user from choosing any alternative boot options, including the recovery mode. Option D is incorrect. Chainloading is used to load another boot loader from GRUB, and it‘s not directly related to providing a recovery mode boot option.

Correct Answer: A. uname -v Explanation: The uname command is used to display system information in Linux. The -v option specifically shows the version of the kernel, including the date and time when it was built. Option B is incorrect. The -n option with the uname command displays the network node hostname, not the kernel version. Option C is incorrect. The -o option with the uname command displays the name of the operating system, not the kernel version. Option D is incorrect. There is no -l option with the uname command.

Correct Answer: B. BIOS/UEFI -> Boot Loader -> Kernel -> Init Process -> System Services Explanation: The boot process starts with the BIOS (or UEFI on newer systems), which initializes the system hardware and then hands over control to the Boot Loader. The Boot Loader, in turn, loads the Kernel. The Kernel, once loaded, starts the Init Process (or its modern equivalents like systemd or Upstart), which subsequently starts the System Services and completes the boot process. Option A is incorrect. The boot process doesn‘t start with the Boot Loader; it begins with the BIOS or UEFI. Option C is incorrect. The BIOS or UEFI doesn‘t hand control directly to the Kernel; the Boot Loader comes in between. Option D is incorrect. Again, the boot process doesn‘t start with the Boot Loader; it begins with the BIOS or UEFI.

Correct Answer: B. SysVinit starts services sequentially, while systemd can start them concurrently Explanation: One of the primary advantages of systemd over SysVinit is its ability to start services concurrently, thereby potentially speeding up the boot process. SysVinit, on the other hand, starts services one after the other based on their order in the init scripts. Option A is incorrect. It‘s the other way around. systemd uses a binary log system called journald, whereas SysVinit typically logs in plain text. Option C is incorrect. SysVinit is older. systemd is relatively newer and is designed to address some of the shortcomings of SysVinit. Option D is incorrect. systemd has built-in service management capabilities using systemctl and unit files, while SysVinit often relies on separate init scripts for each service.

Correct Answer: B. Swap space should be twice the size of RAM Explanation: Traditionally, a common recommendation was to set the swap space to be twice the size of RAM, especially when RAM was limited (e.g., 1 GB or less). However, with modern systems having much more RAM, the appropriate size for swap space can vary based on specific use-cases and system configurations. Still, twice the RAM size is a recognized rule of thumb for many setups. Option A is incorrect. While some systems might allocate swap space to be half the size of RAM, especially when RAM is abundant, it‘s not the traditional rule of thumb. Option C is incorrect. In systems with a large amount of RAM, setting swap equal to RAM can be appropriate. But, it‘s not the conventional wisdom from earlier times. Option D is incorrect. Allocating swap space five times the size of RAM is excessive and is not a standard recommendation.

Correct Answer: A. rd.driver.blacklist=driver_name Explanation: The kernel boot parameter rd.driver.blacklist=driver_name is used to prevent a specific driver from being loaded during the boot process, which can be useful in cases where a faulty driver is preventing the system from booting properly. Option B is incorrect. ro quiet boots the system in read-only mode and suppresses most boot messages. It doesn‘t affect driver loading. Option C is incorrect. nosplash disables the splash screen during boot but doesn‘t affect driver loading. Option D is incorrect. vga=normal sets the VGA mode to normal but doesn‘t blacklist any drivers.

Correct Answer: A. lsmod | grep eth_module Explanation: By using lsmod piped into grep, you can filter the output to show only lines containing “eth_module“. The output will show how many instances of that module are in use. Option B is incorrect. modprobe does not have an “info“ option. Option C is incorrect. While /proc/modules contains the list of loaded modules, lsmod presents this data in a more readable format, showing how many instances of each module are in use. Option D is incorrect. modinfo provides details about a module, but it doesn‘t show how many instances of the module are currently in use.

Correct Answer: A. man tar Explanation: To access the manual page of a command in Linux, the man command followed by the command name (in this case, tar) is used. This will open the manual page of the specified command which contains detailed information about the command and its options. Option B is incorrect. The -k option with man command is used to search the manual page descriptions for keywords. It won‘t open the tar manual page directly. Option C is incorrect. The –man option is not valid with the tar command. To view the manual page, the man command should be used instead. Option D is incorrect. The help command in Linux is generally used to get help for shell built-ins and not for viewing the manual pages of commands. To view the manual page, the man command should be used.

Correct Answer: D. -E resize=1 Explanation: The -E option allows specifying extended options. The resize=1 option ensures that the filesystem is created with resize inodes, facilitating easy future resizing. Option A is incorrect. The ′-T′ option is used to specify the filesystem type and “resizable“ is not a valid value for it. Option B is incorrect. There isn‘t a ′-R′ option in mke2fs for this purpose. Option C is incorrect. While ′-E′ is the right flag, simply stating ′resize′ isn‘t the correct way to set the filesystem for easy resizing.

Correct Answer: B. initctl list Explanation: The initctl list command is used within the Upstart system to provide a list of jobs and their current states. Upstart uses initctl as its primary command-line interface. Option A is incorrect. There is no command named upstart –list. Option C is incorrect. While it might seem logical to have a command like upstartctl, in reality, Upstart uses initctl as its primary interface. Option D is incorrect. systemctl is associated with the systemd init system, not Upstart.

Correct Answer: C. systemctl mask nginx Explanation: The systemctl mask command is used with systemd to prevent a service from being started, even manually. Masking is stronger than disabling a service since it links the service file to /dev/null, making it impossible to start the service until it‘s unmasked. Option A is incorrect. The systemctl stop command will simply stop the service but does not prevent it from being started again. Option B is incorrect. The systemctl disable command will prevent the service from starting at boot, but it can still be started manually. Option D is incorrect. There is no systemctl pause command in systemd.

Correct Answer: C. Check the BIOS settings to see if the drive is detected Explanation: Before the operating system starts, the BIOS performs an initial check on the connected hardware. If a hard drive isn‘t detected in the BIOS settings, it means the system isn‘t recognizing the drive at the hardware level, which would prevent it from being available to any operating system installed on the machine. Option A is incorrect. While it‘s essential for a drive to have a valid file system to be usable within Linux, it‘s not required for the drive to be merely detected at the hardware or BIOS level. Option B is incorrect. The Linux /dev/ directory will only display drives that the operating system recognizes. If the drive isn‘t detected in the BIOS, it won‘t appear in /dev/. Option D is incorrect. fdisk -l will display drives recognized by Linux, but if a drive isn‘t detected in the BIOS, it won‘t appear in the fdisk -l output either.

Correct Answer: C. md5sum linux-distro.iso Explanation: The md5sum command computes and checks MD5 message digest, which can be used to verify the integrity of files. By running md5sum on the downloaded file, you will generate its MD5 checksum, which can then be compared with the provided checksum for validation. Option A is incorrect. The ′grep′ command is used for pattern searching, not for generating checksums. Option B is incorrect. The ′head′ command displays the beginning of a file, it doesn‘t generate checksums. Option D is incorrect. The ′cat′ command simply displays the content of a file; it doesn‘t compute its MD5 checksum.

Correct Answer: A. Set a timeout for the GRUB menu Explanation: By setting a timeout for the GRUB menu, you allow the system to display the menu for a specific number of seconds before booting the default option. This gives you the chance to select an alternative boot location if needed. Option B is incorrect. GRUB does not have a “last known good configuration“ option like some other boot loaders. Option C is incorrect. Removing all entries except the default from the GRUB menu will prevent the user from choosing an alternative boot location. Option D is incorrect. Increasing the boot delay doesn‘t provide a mechanism to select alternative boot options, it just delays the boot process.

Correct Answer: C. Restart the system and access the GRUB menu Explanation: By restarting the system and accessing the GRUB menu, you can interact with the boot loader directly, allowing you to verify boot entries, try different boot parameters, or boot into different kernels. This is the most direct way to confirm that changes to the GRUB configuration are correctly applied and functional. Option A is incorrect. Checking system logs is a good practice after booting to identify any issues. However, it doesn‘t directly allow interaction with the boot loader. Option B is incorrect. grub-mkconfig is used to generate a new GRUB configuration file. While useful after making changes to GRUB settings, it‘s not a method to directly interact with the boot loader. Option D is incorrect. The fsck command checks the integrity of filesystems. It doesn‘t provide a way to interact with the GRUB boot loader or verify changes to its configuration.

Correct Answer: B. The system‘s disk I/O will increase, leading to slower performance Explanation: Swap space is an area on the hard drive that the system uses as “virtual memory“ when it runs out of RAM. When the system uses swap heavily, it has to read from and write to the disk more frequently. Since disk access is much slower than RAM access, this can lead to a significant reduction in system performance due to increased disk I/O. Option A is incorrect. Linux systems don‘t automatically shut down when heavily utilizing swap. Instead, they might become much slower or, in extreme cases, become unresponsive. Option C is incorrect. Heavy swap usage does not directly impact network bandwidth. It affects disk I/O. Option D is incorrect. Linux systems cannot automatically upgrade their physical RAM. Such hardware changes need manual intervention.

Correct Answer: A. sort -r employee.txt Explanation: The -r option with the sort command sorts lines in reverse order, which means it will sort the names in reverse alphabetical order in this context. Option B is incorrect. The ′-o′ option is used to specify the output file for the sorted result but requires a file name to be provided after the option. Option C is incorrect. There‘s no ′–alphabetic′ option for the ′sort′ command. By default, ′sort′ will order lines in alphabetical order (for text) without this option. Option D is incorrect. The ′-n′ option is used to sort lines numerically. Since the file contains names, this option is not suitable.

Correct Answer: C. sed -i ‘s/0$//‘ products.txt Explanation: The -i option edits the file in place. The regular expression s/0$// removes the trailing zero at the end of each line. Option A is incorrect. This command replaces two zeros at the end with one zero, which doesn‘t solve the problem. Option B is incorrect. While it removes the trailing zero, it doesn‘t modify the original file but instead outputs the result to the terminal. Option D is incorrect. The pattern ′$0′ is not a valid regex for matching a trailing zero.

Correct Answer: C. grub-install –boot-directory=/boot /dev/sda Explanation: The grub-install command is used to install the GRUB bootloader to a device. By default, it installs GRUB to the MBR of the specified device. The –boot-directory option specifies the location of the /boot directory, which is typically where the GRUB configuration and modules are located. Option A is incorrect. Installing GRUB to /dev/sda1 would install it to the first partition, not the MBR of the drive. Typically, you‘d want to install GRUB to the MBR, which is denoted by the drive name without a partition number. Option B is incorrect. The –root option is not a valid option for grub-install. The appropriate option for specifying the location of the /boot directory is –boot-directory. Option D is incorrect. This command attempts to install GRUB to a directory rather than a device, which is not the correct usage of the grub-install command.

Correct Answer: A. init 3 Explanation: The init command is used to change runlevels in SysV-style init systems. By specifying a number (representing the desired runlevel) as an argument, the system will attempt to transition to that runlevel. In this case, init 3 will transition the system to runlevel 3. Option B is incorrect. The runlevel command is used to view the current and previous runlevels, but it does not have a set option to change runlevels. Option C is incorrect . sysctl is used for modifying kernel parameters at runtime, not for changing runlevels. Option D is incorrect. There‘s no standard command named level to change runlevels.

Correct Answer: A. lsblk -f Explanation: The lsblk -f command lists all block devices and their corresponding filesystems, labels, and UUIDs, providing an easy way to identify the UUID of a specific partition. Option B is incorrect. ′fdisk -l′ lists partition tables but does not display UUIDs. Option C is incorrect. The ′mount′ command with ′grep′ will show currently mounted filesystems and their mount points, but not UUIDs. Option D is incorrect. ′/proc/partitions′ shows the partitions and their sizes but does not display UUIDs.

Correct Answer: B. To initialize and test system hardware components Explanation: The BIOS (Basic Input/Output System) initializes and tests the system hardware components, like the processor, RAM, and disk drives, before loading the primary operating system loader. This ensures the hardware is operational and ready for the operating system to be loaded. Option A is incorrect. The BIOS does not load the Linux kernel or any other OS kernel into memory. That role is typically handled by boot loaders like GRUB. Option C is incorrect. Managing installed software packages is not a function of the BIOS. This task is typically managed by package managers within the operating system. Option D is incorrect. Assigning IP addresses is a function managed by the operating system or dedicated devices on the network, not the BIOS.

Correct Answer: A. systemctl set-default runlevel3.target Explanation: With systemd, the systemctl set-default command is used to set the default boot target. The target equivalent to the old runlevel 3 (multi-user mode without a graphical interface) is runlevel3.target. Option B is incorrect. The systemctl isolate command is used to switch between targets during the current session, but it does not set the default boot target. Option C is incorrect. This command sets the default boot target to graphical mode, which includes the GUI. Option D is incorrect. There is no systemctl default command in systemd.

Correct Answer: C. update-grub2 Explanation: After making changes to the /etc/default/grub file, the update-grub2 command should be run to generate a new grub.cfg file, which is the actual configuration file read by GRUB 2 during boot. This ensures that the new settings are used the next time the system is booted. Option A is incorrect. There isn‘t a standard command named grub2-update for GRUB 2. Option B is incorrect. grub-install is used to install the GRUB bootloader to a specified device, not to update the configuration. Option D is incorrect. grub-set-default is used to set the default entry for the next boot, not to update the configuration.

Correct Answer: C. mount -t ext4 /dev/sda3 /mnt/data Explanation: To manually mount a filesystem, the mount command is used. The -t option specifies the type of filesystem (in this case, ext4). The device to be mounted is /dev/sda3, and the target directory is /mnt/data. Option A is incorrect. The filesystem type specified is ′ext3′ while Emily wants to mount an ′ext4′ filesystem. Option B is incorrect. The order of arguments is incorrect; the device should come before the mount point. Option D is incorrect. The target directory ′/mnt/data′ is missing.

Correct Answer: B. cat ~/important.txt Explanation: Option B is correct because it uses the tilde (~) to represent the user‘s home directory, followed by the file name “important.txt.“ This allows you to correctly specify the file‘s path in your home directory. Option A is incorrect. It uses an absolute path (“/important.txt“), which does not refer to the file in the user‘s home directory. Option C is incorrect. It uses an absolute path (“/home/yourname/important.txt“), which is unnecessarily specific and does not use the user‘s home directory shortcut. Option D is incorrect. It uses a relative path (./important.txt), which may not work if you are not in your home directory.

Correct Answer: B. The ability to boot from disks larger than 2 terabytes in size Explanation: UEFI (Unified Extensible Firmware Interface) replaces the traditional BIOS and provides numerous advantages, including support for booting from large disks (over 2TB), better hardware initialization, and support for Secure Boot, among other features. Traditional BIOS systems were limited by the MBR (Master Boot Record) partition scheme, which couldn‘t handle disks larger than 2TB. UEFI systems typically use the GPT (GUID Partition Table) partitioning scheme, which can support much larger disks. Option A is incorrect. UEFI does not skip hardware initialization; in fact, it does a more advanced initialization of hardware compared to traditional BIOS. Option C is incorrect. UEFI does not specifically enhance support for 32-bit operating systems. Its advantages are more related to hardware support and extensibility. Option D is incorrect. UEFI does not eliminate the need for a bootloader. Bootloaders like GRUB2 have been updated to work with UEFI, and they play a crucial role in loading the operating system.

Correct Answer: C. Secure Boot ensures that only digitally signed software can run at boot time Explanation: Secure Boot is a feature of UEFI that ensures that the system boots using only software that is signed with a recognized signature. This is a security measure to ensure that bootloaders, kernels, and drivers that have not been tampered with and are from trusted vendors are loaded during the boot process. Option A is incorrect. Secure Boot does not encrypt the hard drive. Encryption is a separate function and is not related to the boot verification process of Secure Boot. Option B is incorrect. While UEFI might offer better support for dual booting, this is not the purpose of Secure Boot. Secure Boot is about ensuring the integrity of the boot process. Option D is incorrect. Secure Boot does not necessarily speed up the boot process. It adds a verification step to ensure the integrity and authenticity of the boot software.

Correct Answer: C. grub > root (hd0,0) > setup (hd0) Explanation: When using GRUB Legacy, to install it to the MBR, one often starts the grub shell and then uses commands like root to specify the root partition and setup to determine where to install the bootloader. In this case, (hd0,0) refers to the first partition on the first hard drive and (hd0) refers to the first hard drive itself. Option A is incorrect. grub-install is used for GRUB 2, not for GRUB Legacy. Option B is incorrect. grub-setup is not the standard command used for installing GRUB Legacy. Option D is incorrect. grub-mkconfig is a command related to GRUB 2 and is used to generate the grub.cfg file, not the menu.lst of GRUB Legacy.

Correct Answer: B. less /var/log/biglog.txt Explanation: The less command is a text file viewer that provides an interactive interface, allowing you to scroll, navigate, and search within large files seamlessly. Option A is incorrect. While ′grep′ can search for specific patterns in a file, it doesn‘t provide an interactive way to navigate through the file. Option C is incorrect. The ′head′ command shows only the beginning of a file, typically the first ten lines. Option D is incorrect. The ′cat′ command displays the entire content of a file but does not provide an interactive navigation feature.

Correct Answer: C. /home Explanation: The /home directory is traditionally used for user-specific data, including personal files and configuration files. By creating a separate partition for /home, you can ensure that large files stored in user directories won‘t impact the root or other critical system directories. Option A is incorrect. The /usr directory is used for user utilities and applications, not for personal user data. Option B is incorrect. The /mnt directory is typically used for temporarily mounted filesystems, not for permanent mount points like user home directories. Option D is incorrect. The /etc directory is used for system configuration files and should not be used for storing personal user data.

Correct Answer: A. bzcat *.bz2 | grep “Report“ Explanation: To search within multiple compressed .bz2 files without decompressing them, Max can use bzcat to read the contents and then pipe (|) the output to grep to search for the word “Report“. Option B is incorrect. Using cat on compressed files will provide binary data, which isn‘t readable. The bzip2 -d command in this sequence would not function as intended. Option C is incorrect. The bzip2 -d command decompresses the files, which Max does not want to do. Option D is incorrect. Using grep directly on compressed files will not provide the desired results because it won‘t be able to search within the compressed binary data.

Correct Answer: B. FAT32 Explanation: The EFI System Partition (ESP) needs to be formatted with the FAT32 filesystem when setting up for UEFI boot. This is a requirement outlined in the UEFI specification, making it the standard across UEFI-based systems. Option A is incorrect. While ext4 is a common filesystem used in Linux for many partitions, it‘s not used for the EFI System Partition. Option C is incorrect. XFS is another filesystem used in Linux, but not for the ESP. Option D is incorrect. Btrfs (B-tree filesystem) is a modern filesystem in Linux that supports many advanced features, but it‘s not used for the ESP.

Correct Answer: B. Create a separate partition for /var and mount it at /var Explanation: By creating a separate partition for /var and mounting it at the /var mount point, you ensure that if /var fills up due to logs or other data, it won‘t consume space on the root filesystem, thereby preventing potential system issues. Option A is incorrect. Mounting /var within the root filesystem does not isolate the space used by /var from the root filesystem. Option C is incorrect. Creating a symbolic link does not provide partition isolation. If /var fills up, it will still affect the filesystem it‘s linked to. Option D is incorrect. Setting a disk quota controls the amount of disk space users can consume but doesn‘t prevent the /var directory itself from filling up the root filesystem if they are on the same partition.

Correct Answer: A. history 5 Explanation: The history command in Linux is used to display the command history list. By providing a number as an argument, like history 5, it will display the last 5 commands executed. Option B is incorrect. There‘s no -5 option in the history command to display the last 5 commands. Option C is incorrect. There isn‘t a –last option available for the history command. Option D is incorrect. Using a +5 would not retrieve the last 5 commands. Moreover, there‘s no such valid usage in the history command.

Correct Answer: C. lsmod Explanation: The lsmod command displays all the currently loaded kernel modules. This tool reads the /proc/modules file and presents it in a user-friendly format. Option A is incorrect. lsmod doesn‘t require the “list“ argument to display the loaded modules. Option B is incorrect. modprobe -l is used to show all available modules, not the ones that are currently loaded. Option D is incorrect. The /etc/modules file lists modules to be loaded at boot time, not the modules that are currently loaded.

Correct Answer: B. fsck.ext4 /dev/sda1 Explanation: The fsck.ext4 command is used to check and repair ext4 filesystems. Running this on a device, like /dev/sda1, will check for inconsistencies and attempt to fix them. Option A is incorrect. The ′mkfs.ext4′ command is used to create a new ext4 filesystem. Using it would erase the data on the specified partition. Option C is incorrect. The ′mount′ command is used to mount filesystems. While mounting a problematic filesystem can sometimes reveal issues, it does not perform repairs. Option D is incorrect. The ′parted′ command is a disk partitioning and partition resizing tool. It does not repair filesystems.

Correct Answer: C. lsusb -t Explanation: The lsusb -t command provides a hierarchical view of USB buses and connected devices, including their speeds. It allows you to visually confirm whether a device is operating at USB 3.0 speeds. Option A is incorrect. While grep 3.0 might seem like a logical choice, USB descriptors do not usually have “3.0“ in their string. Therefore, this might not reliably detect USB 3.0 devices. Option B is incorrect. lspci is used to list PCI devices, and while it might show USB controllers, it won‘t detail individual USB devices. Option D is incorrect. lsmod shows loaded kernel modules, and while usb3 might relate to a USB 3.0 module, it won‘t necessarily show if a USB 3.0 device is connected.

Correct Answer: B. NTFS Explanation: While Linux natively uses ext4 and other filesystem types, NTFS is a widely-supported filesystem due to its use in Windows environments. Linux can read and write to NTFS partitions, making it a good choice for shared partitions on dual-boot systems where the other OS is Windows. Option A is incorrect. While ext4 is the default and widely used filesystem for Linux, it‘s not as universally supported across different OSes as NTFS. Option C is incorrect. btrfs is a newer Linux filesystem and, while powerful, is not as universally supported as NTFS for dual-boot scenarios. Option D is incorrect. A swap partition is used for virtual memory and isn‘t suitable for file storage or sharing between operating systems.

Correct Answer: B. lspci | grep Ethernet Explanation: The lspci command is used to display information about PCI buses in the system and devices connected to them. By piping its output to grep, you can filter the results to show only lines containing the word “Ethernet“, which will reveal details about the Ethernet card, including its type and vendor. Option A is incorrect. lsmod displays loaded kernel modules. While you might see an Ethernet-related module, it doesn‘t directly provide information about the type or vendor of the Ethernet card. Option C is incorrect. lsusb is for USB devices, not PCI devices like most Ethernet cards. Option D is incorrect. modinfo displays information about a specific kernel module, not hardware details.

Correct Answer: B. du -sh /data Explanation: The du -sh /data command displays the total disk usage of the /data directory in a human-readable format (like K, M, G) and suppresses the display of individual disk usage for its subdirectories. Option A is incorrect. ′du /data′ would display the disk usage of the ′/data′ directory and all its subdirectories individually, not giving just the grand total. Option C is incorrect. The ′-a′ flag with ′du′ would show the disk usage of all files and directories in ′/data′, not just the grand total. Option D is incorrect. ′du –exclude=/data/*′ would exclude all files and subdirectories inside ′/data′ from the disk usage report, which is the opposite of what Zoe wants.

Correct Answer: D. /home Explanation: In a Linux environment, user-specific data, personal files, settings, and configurations are stored in individual directories under the /home filesystem. It‘s common practice in shared environments to allocate ample space to the /home filesystem to accommodate user data. Option A is incorrect. The /var filesystem is used for variable data files like logs, databases, and web server content. It‘s not typically where user personal data resides. Option B is incorrect. The /boot filesystem contains the bootloader, kernel, and related files necessary for the system to boot. It‘s not intended for user data. Option C is incorrect. The /usr filesystem stores multi-user utilities and applications but not individual user data.

Correct Answer: C. journalctl -b Explanation: The journalctl -b command displays all journal entries collected since the last boot, providing a comprehensive log of everything that happened during the boot process, especially when using systemd. Option A is incorrect. While dmesg displays kernel ring buffer messages which can be useful for hardware and kernel-related issues, it doesn‘t provide comprehensive details on services and units started by systemd. Option B is incorrect. While /var/log/syslog provides a lot of system logging information, it‘s not specifically tailored to show only boot events. Option D is incorrect. /var/log/boot.log does contain boot messages, but its content might vary based on the distribution and may not be as detailed as the journalctl -b output.

Correct Answer: C. df -h Explanation: The df -h command shows the amount of free disk space on the system in a human-readable format, such as in gigabytes (G) and megabytes (M). Option A is incorrect. While the ′df′ command displays free disk space, it does not do so in a human-readable format. Option B is incorrect. The ′df -T′ command shows the type of filesystem along with disk usage but not specifically in a human-readable format. Option D is incorrect. The ′df –total′ command adds a row at the end which displays the total amounts, but not in a human-readable format.

Correct Answer: A. fsck -a /dev/sda2 Explanation: The fsck -a /dev/sda2 command will attempt to automatically repair the filesystem without manual intervention. This is useful when you expect minor errors and want them fixed without being prompted. Option B is incorrect. Just using ′fsck /dev/sda2′ will check the filesystem and may prompt for manual intervention if it encounters errors. Option C is incorrect. The ′fsck -r /dev/sda2′ command does not exist as a valid ′fsck′ option. Option D is incorrect. The ′fsck -l /dev/sda2′ command is not a valid option for ′fsck′. The ′-l′ option in related utilities like ′e2fsck′ locks the device to guarantee no other program will try to use the partition during the check.

Correct Answer: B. df -i Explanation: The df -i command displays the inode usage of all mounted filesystems. It shows the total number of inodes, used inodes, free inodes, and the percentage of inodes used. Option A is incorrect. The ′free′ command is used to display memory usage, and the ′-i′ flag is not a valid option for it. Option C is incorrect. The ′du′ command is used to estimate file space usage. The ′-i′ option with ′du′ will print the inode number of each file, but it won‘t give an overview of inode usage like ′df -i′. Option D is incorrect. The ′ls -i′ command displays the inode number of files in a directory, not the inode usage of a filesystem.

Correct Answer: A. initctl –version Explanation: To determine the version of Upstart that is currently installed on a system, you can use the initctl –version command. Option B is incorrect. There is no upstart command. Upstart uses the initctl command as its main utility. Option C is incorrect. systemctl is a command associated with the systemd init system, not Upstart. Option D is incorrect. There is no upstartctl command in the Upstart system.

Correct Answer: C. /home Explanation: Placing /home on a separate partition or disk ensures that even if a user fills up their space or a user-specific issue arises, it won‘t affect the overall functioning of the system. This practice also provides better data management, backup strategies, and security measures. Option A is incorrect. The /bin directory holds essential system command binaries that are needed for the system‘s basic operations before /usr is mounted. Separating it doesn‘t specifically offer user-specific data protection. Option B is incorrect. The /etc directory contains all system-related configuration files. While it‘s crucial, it‘s not primarily about user personal files. Option D is incorrect. The /tmp directory is used for system temporary files. While it can be beneficial to separate /tmp for security and performance reasons, it‘s not the primary directory for storing user-specific files.

Correct Answer: D. It holds the UEFI bootloader and related bootable images for UEFI systems Explanation: The EFI System Partition (ESP) is a dedicated partition on UEFI-based systems that holds the UEFI bootloader, drivers, and other bootable images. It‘s essential for the booting process when the system is set to UEFI mode. Option A is incorrect. The ESP is not used for swap space; swap space typically has its dedicated partition or file on Linux systems. Option B is incorrect. Legacy BIOS systems do not utilize the EFI System Partition; instead, they rely on the Master Boot Record (MBR). Option C is incorrect. The ESP does not contain user-specific data. Instead, this type of data is often stored in the /home directory.

Correct Answer: A. cat employees.txt | wc -l Explanation: The command wc -l counts the number of lines in the input it receives. By using cat to display the contents of employees.txt and piping (|) that output to wc -l, Katherine would be counting the lines in her file. Option B is incorrect. Using sort on employees.txt will sort the names in the file, and wc -w counts words, not lines, which isn‘t what Katherine needs. Option C is incorrect. The command echo employees.txt will just print the string “employees.txt“ and wc -l will return 1 since it‘s just one line. Option D is incorrect. The grep command is used for searching, but it‘s not used correctly here. Additionally, it doesn‘t output the contents of the file.

Correct Answer: C. systemctl status Explanation: In systems that use systemd, the systemctl command is used to manage and inspect system units, including services. The command systemctl status provides the status of the specified service. Option A is incorrect. The service command is a utility for initializing and managing services primarily under SysVinit. Though it can work with systemd, it‘s not the native systemd command. Option B is incorrect. initctl is associated with the Upstart init system, not systemd or SysVinit. Option D is incorrect. sysvchk is not a standard command associated with SysVinit or any other init system.

Correct Answer: C. 5 passes Explanation: e2fsck uses five passes to check and potentially repair ext2, ext3, and ext4 filesystems. Each pass has a specific function ranging from checking blocks and sizes to checking for reference counts. Option A is incorrect. e2fsck uses more than just 3 passes for its operations. Option B is incorrect. While close, e2fsck uses 5 passes, not just 4. Option D is incorrect. e2fsck only uses up to 5 passes, not 6.

Correct Answer: A. fsck.ext4 -c /dev/sda2 Explanation: The fsck.ext4 command is specifically designed to check ext4 filesystems. The -c option will check for bad sectors, which can be beneficial after a power outage to verify the integrity of the filesystem. Option B is incorrect. The ′mkfs.ext4′ command is used to create an ext4 filesystem, not to check its integrity. Option C is incorrect. There is no ′chfs.ext4′ command in Linux for checking or changing filesystems. Option D is incorrect. There is no standalone command named ′repair.ext4′. Repairing an ext4 filesystem is done using ′fsck.ext4′.

Correct Answer: C. Boot Loader Explanation: The manufacturer‘s logo is typically displayed by the BIOS or UEFI. If the system does not progress to the OS selection screen or show the boot loader‘s interface, then it‘s likely that the Boot Loader is malfunctioning or not properly installed. Option A is incorrect. The BIOS/UEFI is functioning, at least in part, as it displays the manufacturer‘s logo. Option B is incorrect. The Kernel has not been loaded yet at the stage described, so it cannot be the cause of this particular issue. Option D is incorrect. The Init Process comes into play after the Kernel has been loaded, so it‘s not the culprit in this scenario.

Correct Answer: A. lsusb -v | grep -E ‘Vendor|Product‘ Explanation: The lsusb -v command provides verbose information about USB devices, including the Vendor ID and Product ID. By using grep, you can filter out the specific lines containing these details. Option B is incorrect. lspci lists PCI devices and will not provide detailed information about individual USB devices or their IDs. Option C is incorrect. modinfo displays information about a kernel module, not details of specific hardware devices. Option D is incorrect. While dmesg can show logs related to USB device connections, it may not consistently provide the vendor and product IDs, especially if the logs have aged out or if the system has been up for a long time.

Correct Answer: A. unset DB_USER Explanation: The unset command is used to remove variables or functions from the shell environment. In this case, unset DB_USER will completely remove the variable DB_USER from Jane‘s session. Option B is incorrect. Using set DB_USER=““ is not a valid command to set a variable, and even if it were, it would only set DB_USER to an empty string instead of removing it. Option C is incorrect. The export DB_USER=null command will set the DB_USER variable to the string “null“ and not remove it. Option D is incorrect. The DB_USER=0 command will set the value of DB_USER to 0, but it will not remove the variable.

Correct Answer: A. journalctl -u sshd Explanation: Using journalctl -u sshd allows the administrator to filter the journal logs for messages from the sshd service unit. This provides a focused view of logs related to the SSH daemon. Option B is incorrect. While grepping for sshd can provide relevant log messages, it is less precise than filtering by service unit with -u. Option C is incorrect. The service name is not correct (ssh should be sshd), making the command ineffective for the desired purpose. Option D is incorrect. The -f option will “follow“ the journal, showing new messages as they appear, but it does not filter by service.

Correct Answer: D. type ls Explanation: The type command is used to describe how a command name is interpreted in the shell. It will indicate if a command is a shell built-in, an alias, or an external command, among other possibilities. Option A is incorrect. The which command only returns the path of an external command. It won‘t indicate if ls is a built-in or alias. Option B is incorrect. The locate command is used to find the location of files and directories in the filesystem. It‘s not meant to distinguish command types. Option C is incorrect. The find command is used to search for files and directories based on specific criteria. It‘s not intended to distinguish between command types.

Correct Answer: D. journalctl -b Explanation: The journalctl -b command is used to show journal entries for the current boot. It provides a way for administrators to quickly view messages and logs related to the latest boot process, making it easier to diagnose recent issues. Option A is incorrect. There is no –boot option for journalctl. Option B is incorrect. The -r option is used to display the most recent journal entries last (reverse). Option C is incorrect. –list-boots will list boot numbers, their IDs, and the timestamps, but it won‘t display the log entries.

Correct Answer: D. which grep Explanation: The which command is used to show the full path of shell commands, allowing users to determine which executable would be run when entered on the command line. If grep is an alias or a function, which won‘t return its path. Option A is incorrect. The locate command searches the filesystem for files with the specified name. However, it won‘t differentiate between the system‘s default binary and other files named grep. Option B is incorrect. While type can tell if grep is an alias, function, or binary, it may not always show the full path to the binary. Option C is incorrect. Using find would search the entire filesystem for any file named grep, which can be time-consuming and may return multiple unrelated results.