Linux Essentials The Linux Operating System: 178 practice questions

12 of the 178 The Linux Operating System questions in the Certsqill Linux Essentials bank, shown in full below. Each one carries an explanation for every option, not just the correct one — the wrong answers are where the marks go.

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1. A stable release with an appropriate support lifecycle: Which choice best fits?

1. A nightly development build intended for experimentation.

   Development builds prioritize ongoing changes and testing rather than predictable production behavior.
2. A beta release chosen to obtain features before the stable release.

   Beta releases are intended for pre-release testing, not the stated priority of production predictability.
3. A stable release with an appropriate support lifecycle. ✓

   A stable release is intended for predictable normal use, and its support lifecycle suits ongoing production needs.
4. The release with the lowest purchase price, regardless of compatibility.

   Price alone does not establish hardware, application, support, or operational suitability.

Choose a stable release with suitable support for production use.

2. RAM used as working memory: Which component is described?

1. An SSD used for persistent storage.

   An SSD retains stored data without power, so it is not volatile working memory.
2. RAM used as working memory. ✓

   RAM holds active program data while powered and is volatile when power is removed.
3. The power supply unit.

   A power supply provides electrical power; it does not hold the program's working data.
4. The motherboard firmware.

   Firmware is stored persistently and is not the ordinary volatile workspace for running programs.

RAM is volatile working memory used by running programs.

3. Place the system-wide configuration under `/etc`: What is the relevant correction?

1. Place the system-wide configuration under `/etc`, using the application's required path. ✓

   `/etc` conventionally contains host and system-wide configuration, unlike the user's home directory.
2. Move the file into `/var/log`, because applications read configuration from logs.

   `/var/log` conventionally contains log files, not the standard location for system-wide configuration.
3. Place the file in `/boot`, because all application startup settings belong there.

   `/boot` contains boot-related files and is not the general system-wide configuration directory.
4. Rename the file with a `.log` suffix so the application discovers it.

   A filename suffix does not relocate configuration into the conventional system configuration hierarchy.

`/etc` conventionally stores system-wide configuration; `~/etc` is the user’s home directory.

4. Add a default route via `192.168.1.1`: What prerequisite is missing?

1. Add a default route via `192.168.1.1`. ✓

   A default route supplies the next hop for destinations outside the local subnet.
2. Assign `127.0.0.1` to `eth0` as another address.

   `127.0.0.1` is loopback and cannot forward traffic to another network.
3. Replace the `/24` prefix with a wider subnet prefix.

   Changing the prefix does not provide a router for external destinations and would not address the stated missing route.
4. Add a DNS server entry for the internet address.

   DNS resolves names; it does not route packets beyond the local subnet.

The laptop needs a default route through a reachable router.

5. Choose a stable release with suitable support: Which choice best fits these requirements?

1. Choose a release matching the office’s applications and hardware.

   Compatibility matters, but this choice does not explicitly ensure continuing security support or production stability.
2. Choose a beta release for newer software.

   A beta release is intended for testing and may contain unresolved defects or changing behavior.
3. Choose a stable release with suitable support. ✓

   A stable, supported release is more appropriate for predictable operation and ongoing maintenance.
4. Choose the cheapest release, regardless of compatibility and support.

   Low cost alone does not establish suitable applications, drivers, stability, or security updates.

Choose a stable release with suitable application, hardware, and support compatibility.

6. The system can run compatible 64-bit and 32-bit programs: Which statement is correct?

1. The system can run compatible 64-bit and 32-bit programs. ✓

   The stated x86-64 CPU and Linux support permit compatible applications of both architectures.
2. Architecture does not affect application compatibility.

   CPU and operating-system architecture can restrict which executable packages run.
3. The CPU architecture alone guarantees every application package will run.

   Architecture is relevant, but operating-system support, libraries, and application compatibility are also required.
4. The CPU runs only 64-bit programs.

   Compatible 32-bit programs can also run when the operating system supplies the necessary support.

The stated system supports compatible programs of both 64-bit and 32-bit architectures.

7. Run `less /var/log/app.log`: Select TWO least disruptive actions to inspect recent or ongoing log data.

Select two. More than one option is correct — every correct one is ticked below.

1. Run `: > /var/log/app.log`.

   This truncates the log immediately, destroying existing evidence and potentially disrupting later backup inspection.
2. Run `rm /var/log/app.log`.

   Removing the log destroys the file and may interfere with applications or logging services still using it.
3. Run `chmod 000 /var/log/app.log`.

   This removes access permissions and can prevent the backup or logging task from reading the file.
4. Run `less /var/log/app.log`. ✓

   This opens the log for read-only interactive inspection without changing its contents.
5. Run `tail -n 20 /var/log/app.log`. ✓

   This displays the most recent 20 lines without modifying the existing log file.

Use read-only viewing commands such as `tail` and `less`; do not truncate, remove, or block the log.

8. `/etc/hosts` can map a name locally without DNS: Which statement correctly explains the relationship between `

1. The hosts file is restricted to IPv6, while DNS handles IPv4.

   Hosts files can contain both IPv4 and IPv6 mappings, and DNS can resolve both address families.
2. DNS changes interface addresses.

   DNS resolves names to addresses; it does not configure the workstation’s network interface.
3. The hosts file contains only automatically cached DNS replies.

   Administrators can place local hostname mappings in the file; it is not merely an automatic DNS cache.
4. `/etc/hosts` can map a name locally without DNS. ✓

   An entry in `/etc/hosts` can provide local hostname-to-address resolution without requiring a DNS lookup for that name.

`/etc/hosts` provides local mappings; DNS is a separate name-resolution source.

9. `lsusb`: Select TWO commands that can help identify attached hardware during new-user onboarding.

Select two. More than one option is correct — every correct one is ticked below.

1. `lsusb` ✓

   `lsusb` lists devices connected through USB buses, helping identify attached peripherals.
2. `wc -l`

   `wc -l` counts newline characters in input rather than identifying attached hardware.
3. `pwd`

   `pwd` prints the current directory and does not inspect hardware devices.
4. `mkdir`

   `mkdir` creates directories and provides no hardware inventory information.
5. `lspci` ✓

   `lspci` lists devices connected through the PCI bus, such as many network and graphics controllers.

Use `lspci` for PCI devices and `lsusb` for USB devices.

10. It provides connections between major computer components: Select TWO accurate statements about the motherboar

Select two. More than one option is correct — every correct one is ticked below.

1. It provides connections between major computer components. ✓

   The motherboard provides interconnections and sockets or interfaces for components such as the CPU, RAM, and storage.
2. It executes application instructions instead of the CPU.

   The CPU executes instructions; the motherboard connects and supports the system’s components.
3. It stores files persistently in place of the SSD.

   Persistent file storage is provided by the SSD, not by the motherboard’s interconnection circuitry.
4. It supplies all electrical power without a separate power supply.

   The power supply provides electrical power; the motherboard distributes and regulates some supplied power.
5. It connects and supports components such as the CPU, RAM, and storage interfaces. ✓

   The motherboard supplies the platform that connects major components and provides their compatible interfaces.

A motherboard connects and supports major components; it is neither the CPU, storage, nor the power supply.

11. The copies were placed outside the configured boot: What mistake was made?

1. The files should have been copied into `/dev` before deletion.

   `/dev` provides device nodes and is not the configured storage location for the kernel and initramfs.
2. The files should have been copied into `/proc`.

   `/proc` is a virtual interface to process and kernel information, not a normal storage location for boot artifacts.
3. The copies were placed outside the configured boot location. ✓

   Copying the files to an arbitrary directory does not make the bootloader use them, and deleting the configured files can prevent booting.
4. The files should have been copied into `/var/log`.

   `/var/log` is for log files, not the kernel and initramfs used by the configured boot process.

The bootloader uses configured boot artifacts; an arbitrary copy under `/home` is insufficient.

12. A listener on a reachable non-loopback address: What prerequisite is missing?

1. A DNS record for `localhost`.

   DNS naming does not make a service listening only on loopback reachable from another workstation.
2. A listener on a reachable non-loopback address. ✓

   The service must listen on an address reachable through the network, subject to routing and firewall policy.
3. A second loopback address on the client.

   Adding loopback addressing on the client does not expose the server’s loopback-only listener.
4. A larger `/var/log` filesystem.

   Log storage capacity is unrelated to whether a network service accepts remote connections.

Remote clients require the service to listen on a reachable non-loopback interface.

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