Correct Answer: C. Linux Standard Base (LSB) Specification Explanation: The Linux Standard Base (LSB) Specification provides a set of standards for software system structure in Linux. The header details like Provides, Required-Start, and Default-Start in init scripts adhere to the LSB specification to ensure consistency and interoperability of init scripts across different Linux distributions. Option A is incorrect. GRUB Specification is related to the GRand Unified Bootloader and doesn‘t dictate init script headers. Option B is incorrect. While the Linux Kernel has configurations, it doesn‘t specify headers for init scripts in the described manner. Option D is incorrect. SysV Init does utilize scripts for initialization, but the specific header details mentioned are from the LSB Specification.

Correct Answer: B. mdadm –detail /dev/md0 Explanation: The –detail option with mdadm provides detailed information about the specified RAID array, including its status, components, and if a rebuild is in progress, the progress of the rebuild. Option A is incorrect. The ′–monitor′ option is used to keep an eye on the RAID arrays by providing periodic reports. It‘s not used for getting detailed information about a specific RAID array. Option C is incorrect. There is no ′–info′ option in ′mdadm′ that works in the described manner. Option D is incorrect. The ′–assemble′ option is used for assembling a previously created RAID array, not for checking its detailed status.

Correct Answer: A. tar -xjf software.tar.bz2 Explanation: The correct command to unpack a tar.bz2 archive is tar -xjf software.tar.bz2. The -x option is used for extraction, -j is used for handling bzip2 compression, and -f specifies the archive file. Option A is incorrect because it uses the appropriate options for extracting a tar.bz2 archive. The other options are incorrect because they use incorrect options or tools for handling tar.bz2 archives. Option B is incorrect because ′bunzip2′ is used to decompress bzip2 files but does not handle the tar part, so the resulting file would still be a tar.bz2 archive. Option C is incorrect because it uses the ′-c′ option, which is used to create a new archive, not to extract files from an existing one. The ′-j′ option is missing for bzip2 compression.

Correct Answer: D. 0xFD Explanation: In the context of disk partitioning for RAID on a Linux system, the hex code 0xFD represents the “Linux RAID autodetect“ partition type. This partition type informs the kernel to treat these partitions as potential members of RAID arrays. Option A is incorrect. 0xA9 is used for NetBSD systems, not for Linux RAID. Option B is incorrect. 0x83 is the generic “Linux“ partition type but is not specific to RAID autodetection. Option C is incorrect. 0x7F is not a standard partition type associated with Linux or RAID configurations.

Correct Answer: A. make myapp Explanation: The correct command to compile a program using make is make , where is usually the default target specified in the makefile. In this case, the target is “myapp,“ so the correct command is make myapp. Option B is incorrect because it includes the unnecessary “compile“ keyword. The correct syntax is simply ′make ′. Option C is incorrect because it uses the ′-f′ option to specify a makefile, but the question states that the makefile is in the same directory and named “myapp,“ so this option is unnecessary. Option D is incorrect because it includes the “install“ keyword, which is not necessary for compiling the program. The task is to compile the program, not install it.

Correct Answer: D. /usr/src Explanation: The default location for storing source files is commonly /usr/src. This directory is a standard location for source code of various software packages on Linux systems. Option A is incorrect because there is no standard directory named ′/var/sourcecode′ for storing source files. The convention is to use ′/usr/src′. Option B is incorrect because ′/usr/local/src′ is not the standard location for storing source files. The convention is to use ′/usr/src′. Option C is incorrect because there is no standard directory named ′/opt/sources′ for storing source files. The convention is to use ′/usr/src′.

Correct Answer: A. route add -net 192.168.5.0 netmask 255.255.255.0 gw 192.168.1.1 Explanation: The route command with the add keyword is used to add routes to the routing table. The -net option specifies a network route, followed by the network address, netmask, and the gateway. Option B is incorrect. The ′route′ command does not use the ′via′ keyword. Option C is incorrect. The ′route′ command doesn‘t have a ′set′ keyword. Option D is incorrect. The ′route′ command does not recognize the ′new′ keyword.

Correct Answer: D. iostat -x 5 Explanation: The iostat -x 5 command reports extended disk statistics with an update every 5 seconds, offering a real-time view of the I/O operations and transfer rates for all block devices. Option A is incorrect. free -m displays memory usage in megabytes. It does not provide information related to disk I/O operations. Option B is incorrect. vmstat provides a summary of system processes, memory, paging, block IO, traps, and CPU activity. Although it does cover block IO, it doesn‘t offer the detailed, real-time I/O statistics for block devices like iostat -x 5 does. Option C is incorrect. sar -d displays I/O statistics for block devices. However, it does not provide real-time monitoring unless combined with an interval. iostat -x 5 is a more direct answer for the requirement.

Correct Answer: C. vmstat 5 60 Explanation: This command runs vmstat every 5 seconds and does this 60 times, which equates to a total of 5 minutes. Option A is incorrect. top -n 5 runs the top command to display a dynamic real-time view of a running system, but the -n option specifies the number of iterations, not the duration. This command won‘t give an average over a 5-minute span. Option B is incorrect. sar -u 300 is a command to gather and report system activity information, where -u reports CPU statistics. However, the 300 here would be interpreted as a file and not a time interval. Option D is incorrect. iostat 300 reports Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions. The 300-second interval indicates that the stats will be collected every 5 minutes, but it doesn‘t guarantee the report will cover a total of 5 minutes.

Correct Answer: B. 192.168.0.10:/data /mnt/data nfs defaults 1 1 Explanation: The correct format for an fstab entry is: . Option B correctly follows this format and specifies the remote NFS share, the mount point, the file system type as nfs, and uses default options with dump and fsck order set. Option A is incorrect. While this option almost looks correct, using ′auto′ instead of ′nfs′ for the file system type is not appropriate for mounting an NFS share. Option C is incorrect. The format is reversed; the file system (source) should come before the mount point (destination). Option D is incorrect. The ′fstab′ configuration doesn‘t use a protocol-style format (′nfs://′) for NFS entries.

Correct Answer: C. /usr/src/linux/Documentation/ Explanation: The /usr/src/linux/Documentation/ directory contains detailed documentation related to kernel components, explaining their functions, configurations, and much more. Option A is incorrect. There isn‘t a standard /usr/src/linux/Docs/ directory for kernel documentation. The correct location is /usr/src/linux/Documentation/. Option B is incorrect. /usr/local/doc/ might contain documentation related to locally installed software, but the standard kernel documentation location is /usr/src/linux/Documentation/. Option D is incorrect. The /etc/ directory contains configuration files and is not a standard location for kernel documentation.

Correct Answer: A. zImage Explanation: The zImage format allows the kernel to be loaded low in memory but can decompress itself anywhere in memory, including high memory. This is especially useful for old systems with memory restrictions below the 1 MB mark. Option B is incorrect. vmlinuz is the compressed, bootable kernel image commonly found in many Linux distributions. It‘s not specific to systems with limited RAM below the 1 MB mark. Option C is incorrect. uImage is related to the U-Boot bootloader and contains metadata and the kernel image but isn‘t specific to the constraints described. Option D is incorrect. There‘s no standard kernel image format named binImage in the Linux kernel.

Correct Answer: C. Mount using UUIDs Explanation: UUIDs (Universally Unique Identifiers) provide a consistent way to identify partitions, regardless of the physical arrangement of drives. This ensures that the correct partition is always mounted, even if device names change due to hardware changes. Option A is incorrect. Device names like ′/dev/sda1′ can change when the physical arrangement of drives is modified. Depending solely on them can lead to wrong partitions being mounted. Option B is incorrect. While labels can provide a more descriptive way to identify partitions, they do not guarantee uniqueness like UUIDs, especially across different systems. Option D is incorrect. Inode numbers are used internally by the filesystem to identify files, not for mounting partitions.

Correct Answer: B. route -n Explanation: The route -n command displays the kernel‘s IP routing table in a numeric format, which means IP addresses are shown instead of hostnames, making the output clearer and faster to read. Option A is incorrect. The ′route′ command does not use the ′show′ keyword to display the routing table. Option C is incorrect. The ′route′ command does not have a ′display′ keyword. Option D is incorrect. The ′route′ command does not use the ′get′ keyword to show the routing table.

Correct Answer: B. –prefix=/usr/local Explanation: The correct option to specify a custom installation path when running the configure script is –prefix=/usr/local. This option allows you to set the prefix directory for installation. Option A is incorrect. Option A is incorrect because the correct option for specifying the installation prefix is ′–prefix′, not ′–install-path′. Option C is incorrect. Option C is incorrect because there is no option named ′–path′ for specifying the installation path in the configure script. The correct option is ′–prefix′. Option D is incorrect. Option D is incorrect because there is no option named ′–dir′ for specifying the installation path in the configure script. The correct option is ′–prefix′.

Correct Answer: C. It‘s a partition dedicated for RAID Explanation: The 0xFD partition type is designated for “Linux RAID autodetect.“ This indicates that the partition is intended for use in a RAID configuration. Option A is incorrect. Swap partitions typically use partition type 0x82 in Linux systems. Option B is incorrect. While ext4 is a popular filesystem for Linux, the partition type 0xFD does not specify the filesystem used; it merely indicates the partition is intended for RAID. Option D is incorrect. The 0xFD partition type doesn‘t indicate encryption. It specifically denotes that the partition is associated with RAID configurations.

Correct Answer: B. /etc/systemd/system/ Explanation: /etc/systemd/system/ is the directory where custom and locally defined systemd units or their overrides should be placed. Modifications in this directory take precedence over distribution defaults and are preserved across package updates. Option A is incorrect. While ′/usr/lib/systemd/system/′ contains systemd service files provided by the distribution, placing custom configurations or overrides here could result in their loss during package upgrades. Option C is incorrect. ′/var/lib/systemd/′ is not the standard location for service files or their overrides. Option D is incorrect. ′/run/systemd/system/′ is used for runtime service units, and changes made here are temporary and will be lost upon reboot.

Correct Answer: B. bzImage Explanation: The bzImage (big zImage) is a type of compressed kernel image that is suitable for modern computer systems, allowing the kernel image to be larger than the 512KB limitation imposed by the older zImage format. Option A is incorrect. zImage is an older compressed kernel image format which has a limitation of 512KB, making it unsuitable for most modern systems. Option C is incorrect. uImage is associated with the U-Boot bootloader and contains metadata along with the kernel image but doesn‘t address the size constraints described. Option D is incorrect. There‘s no standard kernel image format named binImage in the Linux kernel.

Correct Answer: B. ifstat 2 Explanation: The ifstat command provides a real-time view of network interface statistics. When provided with an interval argument like “2“, it updates the displayed statistics every 2 seconds. Option A is incorrect. netstat -i displays network interfaces and their statistics, but it does not offer real-time monitoring with regular updates. The “2“ argument does not have the desired effect with netstat. Option C is incorrect. sar -n DEV 2 can provide network device statistics every 2 seconds, but ifstat is more direct in providing real-time interface statistics, making it the better choice. Option D is incorrect. iostat reports CPU and disk I/O statistics, not network I/O. The -n option and “2“ argument would not provide the desired information about network interfaces.

Correct Answer: A. UUID=1234-ABCD /media/usbdrive ext4 defaults 0 2 Explanation: Using the UUID ensures that the correct drive is always mounted to the desired location, even if the order in which it‘s detected changes. Option A correctly uses the UUID, specifies the mount point, and uses the ext4 file system with default options. Option B is incorrect. Using ′/dev/sdb1′ might not always refer to the same device if the order of detection changes. Option C is incorrect. The format is not correct; the UUID should precede the mount point. Option D is incorrect. The file system type (′ext4′) shouldn‘t precede the UUID in the ′fstab′ entry.

Correct Answer: A. mdadm –create /dev/md0 –level=5 –raid-devices=3 /dev/sdb /dev/sdc /dev/sdd Explanation: The –create option is used with mdadm to create a new RAID array. The –level option specifies the RAID level (in this case, 5), and the –raid-devices option indicates the number of devices in the RAID. Option B is incorrect. The ′–assemble′ option is used to gather together pre-existing components of a RAID array to activate the array. It is not used for creating a new RAID. Option C is incorrect. There is no ′–init′ option for ′mdadm′, and the syntax provided is incorrect for creating a RAID array. Option D is incorrect. The ′–manage′ and ′–add′ options are used for managing an existing RAID array, such as adding new devices, not for creating a new RAID.

Correct Answer: A. ifconfig Explanation: By default, the ifconfig command without any arguments displays the configuration of all active network interfaces. Option B is incorrect. ′ifconfig -a′ displays the configuration of all interfaces, active or inactive. Option C is incorrect. ′ifconfig eth0′ will only display the configuration for the ′eth0′ interface. Option D is incorrect. ′ifconfig′ does not have a ′list′ sub-command.

Correct Answer: C. mdadm Explanation: mdadm is the Linux utility used to manage and monitor software RAID arrays. It can be employed to create, manage, and monitor RAID devices using the multiple device driver in the Linux kernel. Option A is incorrect. ′fdisk′ is a command-line utility used to manipulate partition tables on a hard disk. It doesn‘t provide features to manage or monitor software RAID arrays. Option B is incorrect. ′hdparm′ provides a command-line interface to retrieve and set ATA and SATA hard disk drive parameters. It is not used for software RAID management. Option D is incorrect. ′fstab′ is a system configuration file on Linux and other Unix-like systems that contains information about major filesystems on the system. It does not offer utilities for RAID management.

Correct Answer: C. The system is facing memory leaks from a faulty application Explanation: Memory leaks from a faulty application can consume all the available RAM and swap space, causing the system to become unresponsive or even initiate an unexpected reboot. Option A is incorrect. The cron daemon is responsible for executing scheduled jobs. While a misconfigured cron job could cause reboots, the scenario specified that there are no jobs scheduled for a reboot. Option B is incorrect. While a misconfigured network interface can cause network-related issues, it is unlikely to cause the system to reboot unexpectedly. Option D is incorrect. A corrupted filesystem might cause boot issues or system errors, but it‘s less likely to cause periodic unexpected reboots.

Correct Answer: C. /usr/src/linux/ Explanation: For many distributions, /usr/src/linux/ is the location where the Linux kernel source code is placed, and this directory is commonly used for kernel patching and building. Option A is incorrect. While /usr/local/src/ may contain source files, the conventional location for the Linux kernel source is /usr/src/linux/. Option B is incorrect. /usr/bin/ is a directory for binary executable files and not the standard location for kernel source code. Option D is incorrect. Although users can store files in their home directories, /home/linux/source/ is not the standard location for the Linux kernel source.

Correct Answer: A. iw wlan0 scan Explanation: The iw command provides detailed information about wireless networking. The iw wlan0 scan command scans for available wireless networks for the “wlan0“ interface. Option B is incorrect. ′ifconfig′ is not used for scanning wireless networks. It‘s mainly used to configure network interfaces. Option C is incorrect. While ′wpa_cli scan_results′ can show the results of a wireless scan, it requires a prior command to initiate the scan and typically works alongside ′wpa_supplicant′. Option D is incorrect. ′netstat -i′ lists network interfaces, not wireless networks.

Correct Answer: C. –bindir=/usr/bin Explanation: The correct option for specifying a different directory for binary executables when running the configure script is –bindir=/usr/bin. This option allows you to set the directory where the binary files will be installed. Option A is incorrect. Option A is incorrect because there is no option named ′–exec-dir′ for specifying the directory of binary executables in the configure script. The correct option is ′–bindir′. Option B is incorrect. Option B is incorrect because there is no option named ′–binary-dir′ for specifying the directory of binary executables in the configure script. The correct option is ′–bindir′. Option D is incorrect. Option D is incorrect because there is no option named ′–bin-path′ for specifying the directory of binary executables in the configure script. The correct option is ′–bindir′.

Correct Answer: B. iostat 5 3 Explanation: The iostat command, when provided with two numerical arguments, interprets the first as the interval in seconds between reports and the second as the count of reports to produce. Thus, iostat 5 3 would produce statistics every 5 seconds, 3 times. Option A is incorrect. iostat 3 would display statistics every 3 seconds indefinitely. Option C is incorrect. iostat -x 3 would display extended statistics every 3 seconds indefinitely. Option D is incorrect. iostat -x 5 3 would produce extended statistics every 5 seconds, but the scenario doesn‘t mention the need for extended statistics.

Correct Answer: C. /usr/src/linux/Documentation/ Explanation: Kernel modules and their functionalities, among other kernel-related details, are usually documented within the /usr/src/linux/Documentation/ directory. Option A is incorrect. The /lib/modules/ directory houses dynamic kernel modules but doesn‘t typically contain their documentation. Option B is incorrect. There isn‘t a standard /usr/src/linux/KernelDocs/ directory. The correct path for kernel documentation is /usr/src/linux/Documentation/. Option D is incorrect. While /usr/share/docs/ might contain documentation for various installed packages, the standard location for kernel documentation is /usr/src/linux/Documentation/.

Correct Answer: D. /usr/src Explanation: The standard directory for storing source files by default is /usr/src. This directory is commonly used to keep the source code for various software packages on Linux systems. Option A is incorrect. because there is no standard directory named ′/usr/sourcecode′ for storing source files. The convention is to use ′/usr/src′. Option B is incorrect. because there is no standard directory named ′/opt/programs/src′ for storing source files. The convention is to use ′/usr/src′. Option C is incorrect. because there is no standard directory named ′/var/lib/source′ for storing source files. The convention is to use ′/usr/src′.

Correct Answer: C. tar -xzf project.tar.gz Explanation: The correct command to unpack a tar.gz archive is tar -xzf project.tar.gz. The options A and B are incorrect because they involve creating or decompressing a gzip file, but they do not handle the tar part. Option D is incorrect because unzip is used for zip archives, not tar.gz archives. Option A is incorrect. because it uses the ′-c′ option, which is used to create a new archive, not to extract files from an existing one. Option B is incorrect. because it uses ′gzip -d′ to decompress a gzip file, but it doesn‘t handle the tar part, so the resulting file would still be a tar.gz archive. Option D is incorrect. because ′unzip′ is used for zip archives, and it won‘t work for tar.gz archives. The correct tool for tar.gz archives is ′tar′.

Correct Answer: A. The /etc/mtab file has been accidentally overwritten or tampered with Explanation: The mount command, by default, refers to /etc/mtab to display currently mounted filesystems. If there‘s a discrepancy between the mount command‘s output and the contents of /etc/mtab, it‘s possible that the /etc/mtab file has been tampered with or there‘s some other issue affecting its contents. Option B is incorrect. The ′mount′ command, by default, refers to ′/etc/mtab′ for its output, not ′/etc/fstab′. Option C is incorrect. ′/etc/mtab′ lists all currently mounted filesystems, not just network-based ones. Option D is incorrect. The ′mount′ command, without options, displays currently mounted filesystems, not unmounted ones.

Correct Answer: D. /run/systemd/system/ Explanation: The /run/systemd/system/ directory is used for runtime service units. Any modifications or additions to this directory are temporary and will be lost after a reboot. This makes it suitable for short-term testing or troubleshooting. Option A is incorrect. ′/etc/systemd/system/′ is where custom and locally defined systemd units or overrides are placed, and changes in this directory persist across reboots. Option B is incorrect. ′/var/lib/systemd/′ does not store service unit files or their overrides. Option C is incorrect. ′/usr/lib/systemd/system/′ contains systemd service files provided by the distribution. While changes can be made here, it‘s not recommended as they may be lost during package updates.

Correct Answer: D. /usr/src Explanation: The default location for storing source files is commonly /usr/src. This directory is a standard location for source code of various software packages on Linux systems. Option A is incorrect. Option A is incorrect because there is no standard directory named ′/usr/sourcecode′ for storing source files. The convention is to use ′/usr/src′. Option B is incorrect. Option B is incorrect because there is no standard directory named ′/opt/programs/src′ for storing source files. The convention is to use ′/usr/src′. Option C is incorrect. Option C is incorrect because there is no standard directory named ′/var/lib/source′ for storing source files. The convention is to use ′/usr/src′.

Correct Answer: D. /etc/rcX.d/ where X is the runlevel number Explanation: In SysV init, the /etc/rcX.d/ directories (where X is the runlevel number) contain symbolic links to the scripts in /etc/init.d/. These symbolic links determine the order and manner (start or stop) in which the scripts are executed for each runlevel. Option A is incorrect. The ′/etc/init.d/′ directory contains the actual init scripts for services but does not manage their execution order or runlevels. Option B is incorrect. ′/etc/rc.d/′ is a directory that may contain init scripts and other directories related to runlevels, but it‘s not the primary place to look for runlevel-specific symbolic links. Option C is incorrect. The ′/etc/sysconfig/′ directory contains configuration files for the system and its services but does not manage service startup for specific runlevels.

Correct Answer: A. ifconfig Explanation: The ifconfig command is used to configure the kernel-resident network interfaces. It is used to set up an interface and assign IP address, broadcast address, etc. directly to an interface on the fly. Option B is incorrect. ′netplan′ is a utility for configuring networking on a system, typically by defining configurations in YAML files. It doesn‘t directly set the IP address of an interface on the fly without touching configuration files. Option C is incorrect. ′networkctl′ is a command used to introspect the state of the network links as seen by systemd. It is not primarily used for directly configuring interfaces. Option D is incorrect. ′nmtui′ stands for Network Manager Text User Interface, which is a TUI-based interface to configure networking. However, it involves a more detailed configuration setup rather than quickly assigning an IP address on the fly.

Correct Answer: A. mnt-data.mountt Explanation: When creating systemd mount units, the filename should reflect the mount point in the filesystem namespace, with slashes (/) replaced by hyphens (-). Thus, for the directory /mnt/data, the appropriate mount unit filename would be mnt-data.mount. Option B is incorrect. This format incorrectly reflects the remote NFS path rather than the local mount point. Option C is incorrect. This format mixes the syntax of a ′systemd′ socket-activated service with a mount unit and doesn‘t apply to this scenario. Option D is incorrect. This does not provide the full path of the mount point; it only provides the last directory.

Correct Answer: B. make clean all Explanation: The correct command to compile the program and then clean the intermediate files is make clean all. This ensures that the “clean“ target is executed first, followed by the “all“ target for compilation. Option A is incorrect. Explanation: Option A is incorrect because the order matters in make commands. In this case, executing “all“ before “clean“ may not achieve the desired result. Option C is incorrect. Explanation: Option C is incorrect because it introduces an unnecessary “compile“ keyword. The correct sequence is to first clean and then compile. Option D is incorrect. Explanation: Option D is incorrect because it only executes the default target, which may not include the cleaning process. The order is crucial, and specifying “clean all“ ensures the correct sequence of actions.

Correct Answer: A. ip addr show Explanation: The ip addr show command lists IP addresses and other information for all active interfaces, making it the direct replacement for the commonly used ifconfig command. Option B is incorrect. ′ip route get′ is used to get the route to a destination, not to show the IP address of active interfaces. Option C is incorrect. ′ip link set′ is used to change the state of an interface (up/down) or modify its properties. It doesn‘t show the IP address. Option D is incorrect. ′ip neigh show′ displays the kernel‘s neighbor cache (ARP cache) and not the details of the network interfaces.

Correct Answer: B. ip link set eth0 down Explanation: The ip link set command allows you to change the state of the network device. Specifying down will disable the “eth0“ ethernet interface. Option A is incorrect. ′ip addr del′ is used to delete an address from an interface, but it does not disable the interface itself. Option C is incorrect. The ′route′ command is used for manipulating IP routing table entries, not for enabling or disabling interfaces. Option D is incorrect. ′netstat -r′ displays routing table information. It is not used for enabling or disabling network interfaces.

Correct Answer: B. /etc/wpa_supplicant.confl Explanation: The wpa_supplicant is a WPA client and IEEE 802.1X supplicant. The configuration file /etc/wpa_supplicant.conf is where SSIDs, passphrases, and other wireless network settings are stored for networks that use WPA or WPA2 security. Option A is incorrect. ′/etc/network/interfaces′ is a Debian-based configuration file for network interfaces but does not directly store WPA or WPA2 passphrase information. Option C is incorrect. There isn‘t a standard ′/etc/wireless/networks′ configuration file in Linux for storing wireless network settings. Option D is incorrect. While ′netplan′ can be used to configure networks, including wireless, it‘s not the primary or typical method for storing WPA/WPA2 passphrases.

Correct Answer: B. /proc/mdstat Explanation: The /proc/mdstat file is the primary source to check the status and configuration of RAID devices on a Linux system. It provides a detailed view of the current status of software RAID arrays and is updated in real time. Option A is incorrect. ′/etc/fstab′ is a system configuration file that contains information about filesystems on the system. While it might list RAID devices being mounted, it does not provide a detailed status or configuration view. Option C is incorrect. ′/etc/mdadm/mdadm.conf′ is the configuration file for ′mdadm′ and might provide details about the RAID array configuration, but it does not offer real-time status updates like ′/proc/mdstat′. Option D is incorrect. ′/etc/raidtab′ was used in older RAID management tools but is not the standard method for checking RAID status in more modern Linux systems using ′mdadm′.

Correct Answer: C. iotop Explanation: iotop is a top-like utility that monitors I/O usage by processes and threads in real-time. This tool allows administrators to pinpoint which processes are the most I/O intensive. Option A is incorrect. While iostat is used for monitoring I/O statistics, it doesn‘t provide real-time information on individual processes and threads. Option B is incorrect. top is a utility for monitoring processes, but its main focus is on CPU and memory usage, not I/O. Option D is incorrect. netstat is used to display network connections, routing tables, and a number of network interfaces, not individual process I/O.

Correct Answer: A. ip route add default via 192.168.1.1 Explanation: The ip route add command allows the user to modify the system‘s routing table. In this case, to add a default gateway with the specified IP address. Option B is incorrect. ′ip addr add′ is used to assign an IP address to an interface, not to set a default gateway. Option C is incorrect. ′ip link set dev eth0 up′ brings up the eth0 interface but doesn‘t add a route. Option D is incorrect. ′ip route del′ is used to remove a route from the system‘s routing table, not to add one.

Correct Answer: B. /etc/mtab dynamically tracks all currently mounted filesystems and their associated attributes Explanation: The /etc/mtab file provides a current list of all mounted filesystems on the system, detailing their mount points, mount options, and other attributes. It is updated dynamically as filesystems are mounted or unmounted. Option A is incorrect. The static filesystem mount points and options read at system boot are defined in ′/etc/fstab′. Option C is incorrect. While on many modern systems ′/etc/mtab′ is indeed a symbolic link to ′/proc/mounts′, this does not capture the primary role of the file itself. Option D is incorrect. UUIDs and other identification methods for filesystems are not the primary content of ′/etc/mtab′.

Correct Answer: B. top Explanation: The top command provides a dynamic real-time view of a running system, including a comprehensive overview of memory usage, such as free, used, buffers, and cached memory. Option A is incorrect. mpstat -P ALL reports processor related statistics for each available processor, including cores. It doesn‘t provide a detailed view of memory usage. Option C is incorrect. sar -r provides memory and swap space utilization statistics but doesn‘t provide as comprehensive or real-time a view as top. Option D is incorrect. iostat -m displays I/O statistics in megabytes, which primarily focuses on input/output operations and not on memory usage details.

Correct Answer: D. /usr/src/linux/Documentation/ Explanation: The /usr/src/linux/Documentation/ directory contains detailed documentation about the kernel, its various subsystems, APIs, and other information. Specific to the kernel version, it is the best place to find the nuances and changes. Option A is incorrect. While the ChangeLog provides information about changes, it is more general and doesn‘t offer the detailed documentation on subsystems or specific features. Option B is incorrect. There isn’t a standard /usr/share/docs/ directory specifically for kernel documentation. Kernel documentation is typically found within the source directory. Option C is incorrect. /proc/version provides the current version of the kernel running and some other basic info, not detailed documentation about the kernel’s changes or features.

Correct Answer: C. iperf3 Explanation: iperf3 is a tool used to measure the maximum TCP and UDP bandwidth performance. When run in client-server mode between two machines, it can effectively measure the throughput of a firewall between those machines. Option A is incorrect. traceroute is used to display the route and measure transit delays of packets across a network. It doesn‘t directly measure firewall throughput. Option B is incorrect. netstat displays active connections and routing tables. It does not measure throughput or performance of a firewall. Option D is incorrect. route displays and modifies the IP routing table. It doesn’t measure the throughput or performance of a firewall.

Correct Answer: C. /usr/src/linux-3.x/Documentation/ Explanation: Kernel documentation, including details about its internals and subsystems, is typically stored in the /usr/src/linux-/Documentation/ directory. Option A is incorrect. There isn’t a standard /etc/kernel/ directory for kernel documentation. Option B is incorrect. /var/lib/ is not a standard location for kernel documentation. Option D is incorrect. There isn‘t a standard command or directory named /usr/bin/kernel-3.x-info for kernel documentation.

Correct Answer: C. A compressed kernel image that can be considerably larger than the old zImage format Explanation: bzImage stands for “big zImage.“ It‘s a compressed kernel image format that was introduced to overcome the size limitation of the older zImage format. Option A is incorrect. zImage, not bzImage, is the kernel image format tailored for older embedded systems with memory limitations. Option B is incorrect. While bzImage is bootable, it is a compressed kernel image. The term “non-compressed, bootable kernel image“ refers to vmlinux. Option D is incorrect. bzImage isn‘t specifically designed for systems with non-standard bootloaders. The kernel image format associated with specific bootloaders (like U-Boot) is uImage.

Correct Answer: C. /usr/src/linux/ Explanation: The standard location where the Linux kernel source code is often stored is /usr/src/linux/. Option A is incorrect. The /etc/ directory primarily contains configuration files and does not house the kernel source code. Option B is incorrect. The /lib/ directory contains library files essential for the system‘s booting and operation but does not store the kernel source code. Option D is incorrect. /var/ primarily contains variable data files, logs, and spool files, but not the kernel source code.

Correct Answer: B. systemd-delta –list-overridden Explanation: The systemd-delta –list-overridden command displays the differences between vendor and local versions of unit files, indicating which vendor versions have been overridden by local versions. Option A is incorrect. There is no ′–type=vendor′ option available for ′systemd-delta′. Option C is incorrect. The ′–type=extended′ option is not valid for ′systemd-delta′. Option D is incorrect. The ′–list-changed′ option is not available. It is ′–list-overridden′ that achieves the desired outcome.

Correct Answer: C. To store distribution-provided systemd service files Explanation: The /usr/lib/systemd/ directory primarily contains systemd service files, targets, and other units provided by the installed distribution packages. It‘s the default location for system-provided units. Option A is incorrect. User-defined and locally customized systemd service files are typically stored in ′/etc/systemd/system/′. Option B is incorrect. Temporary runtime files for systemd services or any other services are not stored in ′/usr/lib/systemd/′. Option D is incorrect. Backup copies of overridden systemd services are not stored here; overridden units are typically placed in ′/etc/systemd/system/′.

Correct Answer: A. systemctl status –lines=5 webapp.service Explanation: The systemctl status command is used to view the status of a service. The –lines option allows the user to limit the number of log lines displayed, so using –lines=5 would show the last 5 log entries. Option B is incorrect. The ′–lines=5′ option should come after the ′status′ keyword and not before for it to be effective. Option C is incorrect. There is no ′log′ sub-command in ′systemctl′. Option D is incorrect. The ′show′ command displays properties of a service or other units, but does not show log entries.

Correct Answer: A. /etc/systemd/system/ Explanation: When administrators want to add or override unit files locally, they should place them in /etc/systemd/system/. This directory takes precedence over the directories where unit files are provided by the distribution. Option B is incorrect. ′/lib/systemd/system/′ contains system service units provided by the installed packages, and while they are read by systemd, it‘s not the proper location for local customizations. Option C is incorrect. ′/usr/lib/systemd/user/′ contains user service units provided by installed packages, not system-wide service units or timers. Option D is incorrect. There is no standard systemd directory named ′/var/lib/systemd/timers/′.

Correct Answer: B. server:/share /mnt/data nfs users,auto 0 0 Explanation: The users option allows any user to mount and unmount the filesystem. The auto option ensures the filesystem is automatically mounted at boot. This makes option B the correct choice for the given requirements. Option A is incorrect. The ′noauto′ option will prevent the filesystem from being automatically mounted at boot. Option C is incorrect. The format of the entry is incorrect; the remote path and local mount point are in the wrong order. Option D is incorrect. While it will be mounted at boot because of the ′auto′ option, the ′noexec′ option wasn‘t a requirement, and there‘s no option to allow users to unmount.

Correct Answer: C. top Explanation: The top command provides real-time view of the processes running in a system and includes information about swap usage among other system metrics. Option A is incorrect. The ′df -h′ command is used to display the amount of disk space used and available on the mounted filesystems, but it doesn‘t show swap usage. Option B is incorrect. ′fdisk -l′ lists partition tables for all devices, but it doesn‘t directly display swap usage. Option D is incorrect. The ′mkswap′ utility is used to set up swap space on a device or in a file, not for checking swap usage.

Correct Answer: B. /proc/mounts is a dynamic file in the proc filesystem that lists all currently mounted filesystems, whereas /etc/mtab might be a symbolic link to it on modern systems Explanation: The /proc/mounts file provides an up-to-date list of all currently mounted filesystems and is generated by the kernel. On many modern systems, to ensure accurate and consistent data, /etc/mtab is often made a symbolic link pointing to /proc/mounts. Option A is incorrect. ′/proc/mounts′ is not deprecated; rather, it‘s a dynamic representation of current mounts provided by the kernel. Option C is incorrect. ′/proc/mounts′ is not just an alias for ′/etc/mtab′, but ′/etc/mtab′ might point to ′/proc/mounts′ as a symbolic link on modern systems. Option D is incorrect. While they might serve similar purposes of listing mounts, they are related, especially given the symbolic link approach on newer systems.

Correct Answer: A. ifconfig eth0 192.168.0.10 netmask 255.255.255.0 Explanation: The ifconfig command, when provided with an interface name, IP address, and the netmask option, sets the IP address and subnet mask for the specified interface. Option B is incorrect. ′ifconfig′ does not use the ′add′ keyword nor CIDR notation in this context. Option C is incorrect. The ′up′ option is used to activate the network interface, not to set its IP address. Option D is incorrect. ′ifconfig′ does not have a ′route′ sub-command.

Correct Answer: B. Cacti Explanation: Cacti is a complete network graphing solution designed to harness the power of RRDTool‘s data storage and graphing functionality. It provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features to map client bandwidth usage over time. Option A is incorrect. mtr combines the functionality of the traceroute and ping programs in a single diagnostic tool. It doesn‘t offer logging or visualization of network traffic data over extended periods. Option C is incorrect. nmap is used for network discovery and security auditing. It cannot log or visualize bandwidth usage over extended periods. Option D is incorrect. dig is a DNS lookup utility. It doesn‘t pertain to network traffic data or bandwidth monitoring.