LFCS Exam Dumps : Linux Foundation Certified System Administrator (LFCS)

Objective: Enable IPv4 packet forwarding on the Linux server and ensure that the setting remains enabled after a system reboot.

In Linux, IPv4 forwarding is controlled by the kernel parameter:

net.ipv4.ip_forward

This parameter determines whether the Linux kernel can forward IPv4 packets between network interfaces.

Value

Meaning

0

IPv4 forwarding disabled

1

IPv4 forwarding enabled

The task requires a persistent configuration, not merely a temporary runtime change.

The official Linux kernel documentation confirms that setting net.ipv4.ip_forward to 1 enables forwarding of IPv4 packets.

Step 1: Connect to the correct Linux server.

The video specifies that this task must be completed on host lfcs00081.

From the candidate terminal, execute:

ssh lfcs00081

This establishes an SSH session with the designated server.

All remaining commands must be executed on this host.

Step 2: Inspect the current IP forwarding configuration.

Execute:

sysctl net.ipv4.ip_forward

This displays the current value of the IPv4 forwarding parameter.

If forwarding is disabled, the output is:

net.ipv4.ip_forward = 0

If forwarding is already enabled, the output is:

net.ipv4.ip_forward = 1

You can also inspect the corresponding kernel interface directly:

cat /proc/sys/net/ipv4/ip_forward

Expected output when forwarding is disabled:

0

The /proc/sys/ hierarchy provides an interface for viewing and modifying runtime kernel parameters.

Step 3: Check the existing persistent configuration.

Before modifying anything, check whether the parameter is already configured elsewhere.

Execute:

sudo grep -RnsE '^[[:space:]]*net\.ipv4\.ip_forward[[:space:]] *=' \

/etc/sysctl.conf /etc/sysctl.d/ \

/run/sysctl.d/ /usr/lib/sysctl.d/ 2 > /dev/null

This searches the relevant sysctl configuration files.

For example, the output might include:

/etc/sysctl.conf:28:net.ipv4.ip_forward=0

This indicates that the existing configuration explicitly disables IPv4 forwarding.

If the parameter appears in multiple files, inspect the effective configuration order before changing it.

Step 4: Enable IPv4 forwarding immediately.

Execute:

sudo sysctl -w net.ipv4.ip_forward=1

sudo executes the command with administrative privileges.

sysctl reads or modifies kernel parameters.

-w writes a new value to a kernel parameter.

net.ipv4.ip_forward=1 enables IPv4 forwarding.

Expected output:

net.ipv4.ip_forward = 1

This change takes effect immediately.

However, this command alone does not guarantee persistence after reboot.

Therefore, additional configuration is required.

Step 5: Create a persistent sysctl configuration file.

The preferred method on a systemd-based Linux system is to create a dedicated file in:

/etc/sysctl.d/

Execute:

sudo nano /etc/sysctl.d/99-lfcs-ip-forward.conf

Add this exact line:

net.ipv4.ip_forward = 1

Save the file.

The complete file should contain:

net.ipv4.ip_forward = 1

Why this works:

/etc/sysctl.d/ stores persistent administrator-defined kernel settings.

.conf files in this directory are read during system startup.

The filename prefix 99- normally positions the file after most package-provided configuration files.

The setting enables IPv4 forwarding whenever it is applied.

The systemd sysctl.d(5) documentation confirms that these configuration files are used to apply kernel parameters during boot.

Step 6: Check for settings that could override the new value.

A particularly important consideration is /etc/sysctl.conf.

On Ubuntu systems using the procps implementation, sysctl --system processes /etc/sysctl.conf after the configuration files in sysctl.d.

Therefore, an existing entry such as:

net.ipv4.ip_forward = 0

inside /etc/sysctl.conf could override the value in the new file when sysctl --system is executed.

Inspect it:

sudo grep -n 'net.ipv4.ip_forward' /etc/sysctl.conf

If an active, conflicting entry is present, edit it:

sudo nano /etc/sysctl.conf

Change:

net.ipv4.ip_forward = 0

to:

net.ipv4.ip_forward = 1

Alternatively, remove the duplicate active entry and rely on the dedicated /etc/sysctl.d/99-lfcs-ip-forward.conf file.

Do not modify unrelated sysctl parameters.

The official sysctl(8) manual documents how --system processes configuration files and how /etc/sysctl.conf can override earlier values.

Step 7: Apply the persistent configuration immediately.

Execute:

sudo sysctl --system

This loads the sysctl settings from the system configuration.

The relevant output should include:

net.ipv4.ip_forward = 1

Review the command output for conflicting settings or errors.

Check the command's exit status immediately:

echo $?

A successful execution should normally return:

0

Step 8: Verify that IPv4 forwarding is enabled in the running kernel.

Execute:

sysctl net.ipv4.ip_forward

Expected:

net.ipv4.ip_forward = 1

Verify through the kernel interface:

cat /proc/sys/net/ipv4/ip_forward

Expected:

1

These two commands confirm the same runtime kernel setting through different interfaces.

Step 9: Verify the persistent configuration file.

Execute:

cat /etc/sysctl.d/99-lfcs-ip-forward.conf

Expected output:

net.ipv4.ip_forward = 1

You can also confirm that the setting remains active after reapplying its configuration:

sudo sysctl --system

sysctl net.ipv4.ip_forward

The final result should remain:

net.ipv4.ip_forward = 1

This confirms both that the runtime setting is enabled and that the system configuration can reapply it successfully.

Step 10: Verify persistence after a reboot, if permitted.

The strongest practical verification is to reboot the server and check the parameter afterward.

Only perform this step if rebooting the exam host is permitted and you can reconnect safely.

Execute:

sudo reboot

After the server finishes restarting, reconnect:

ssh lfcs00081

Then execute:

sysctl net.ipv4.ip_forward

Expected:

net.ipv4.ip_forward = 1

If the value remains 1, IPv4 forwarding has been restored successfully during startup.

Important: A reboot is not necessary to apply the change. sudo sysctl --system is sufficient for immediate activation. Avoid an unnecessary reboot during an exam if the required state can already be verified.

Step 11: Understand why both runtime and persistent changes matter.

There are two separate requirements to consider:

Configuration method

Immediate effect

Persistent after reboot

sudo sysctl -w net.ipv4.ip_forward=1

Yes

No, by itself

Write 1 to /proc/sys/net/ipv4/ip_forward

Yes

No, by itself

Configure /etc/sysctl.d/*.conf

After loading

Yes

Configure /etc/sysctl.conf on the Ubuntu setup

After loading

Yes

sudo sysctl --system

Applies configured values

Does not itself create persistence

The correct solution must leave the runtime parameter enabled and store the configuration in a location that is processed at startup.

Step 12: Confirm that IPv4 forwarding does not require additional configuration for this task.

The question asks only to enable the IP forwarding kernel feature persistently.

It does not request:

Configuring network interfaces.

Creating routing tables.

Adding NAT or firewall rules.

Enabling IPv6 forwarding.

Installing a routing daemon.

Therefore, these additional changes are unnecessary.

Enabling the kernel's forwarding feature allows Linux to forward IPv4 packets, but successful routing between networks can still depend on interface configuration, routing tables, and firewall policies.

Those are separate operational concerns and are not part of the stated task.

Step 13: Perform the final verification.

Execute:

sysctl net.ipv4.ip_forward

Expected:

net.ipv4.ip_forward = 1

Then:

cat /proc/sys/net/ipv4/ip_forward

Expected:

1

Finally:

cat /etc/sysctl.d/99-lfcs-ip-forward.conf

Expected:

net.ipv4.ip_forward = 1

The resulting configuration must satisfy the following:

Requirement

Expected result

IPv4 forwarding enabled

Yes

Runtime kernel parameter

1

Persistent configuration

Present

Settings reapply successfully

Yes

Other kernel parameters

Unchanged unless affected by the kernel's forwarding transition

IPv4 forwarding after reboot

Enabled

Final Solution

Copy commands

# Connect to the correct server

ssh lfcs00081

# Check current IPv4 forwarding status

sysctl net.ipv4.ip_forward

# Enable IPv4 forwarding immediately

sudo sysctl -w net.ipv4.ip_forward=1

# Make the setting persistent

printf 'net.ipv4.ip_forward = 1\n' | \

sudo tee /etc/sysctl.d/99-lfcs-ip-forward.conf

# Check for a conflicting setting in /etc/sysctl.conf

sudo grep -n 'net.ipv4.ip_forward' /etc/sysctl.conf

# Resolve any active conflicting entry if present,

# then apply persistent settings

sudo sysctl --system

# Verify the effective kernel setting

sysctl net.ipv4.ip_forward

# Verify directly through procfs

cat /proc/sys/net/ipv4/ip_forward

# Verify the persistent configuration

cat /etc/sysctl.d/99-lfcs-ip-forward.conf

Alternative Solution — Method Demonstrated in the Video

The candidate in the recording edits:

sudo vim /etc/sysctl.conf

This is also a valid approach on the Ubuntu environment shown.

Inside the file, locate the IPv4 forwarding setting:

#net.ipv4.ip_forward=1

If the line is commented out, uncomment it so it reads:

net.ipv4.ip_forward=1

If an active entry is already set to 0, change it to 1 instead. Ensure there are no contradictory active entries.

Save and apply:

sudo sysctl -p /etc/sysctl.conf

Verify:

sysctl net.ipv4.ip_forward

Expected:

net.ipv4.ip_forward = 1

Both approaches are valid. A dedicated file under /etc/sysctl.d/ is preferable for keeping administrator-specific changes separate, whereas editing /etc/sysctl.conf closely follows the method attempted in the recording. Use one consistent configuration and ensure no conflicting setting overrides it.

Technical Verification and References

The solution has been checked against official Linux and systemd documentation:

Linux Kernel — IP Sysctl Documentation — Defines the IPv4 forwarding parameter and its behavior.

Linux sysctl(8) — Documents runtime modification and applying system configuration.

systemd sysctl.d(5) — Explains persistent kernel settings loaded during startup.

Video verification finding: At approximately 28:20–29:10, the recording shows Task 8 on host lfcs00081. The candidate edits /etc/sysctl.conf and executes a reboot. However, the visible recording does not establish the precise final contents of the file or show a successful post-reboot check of net.ipv4.ip_forward.

Expected result: The Linux system has IPv4 forwarding enabled with net.ipv4.ip_forward = 1, and the setting is configured to remain enabled after reboot.

Objective: Create a new virtual machine using the existing Ubuntu 22.04 disk image, allocate 1024 MiB of RAM, register the virtual machine with libvirt, and ensure virt-install exits without opening an interactive console.

The correct solution uses virt-install with the --import and --noautoconsole options. The --import option is essential because the task provides an existing operating system disk image rather than requesting a fresh installation.

Step 1: Connect to the correct Linux server.

The video specifies that this task must be completed on host lfcs00083.

From the candidate terminal, execute:

ssh lfcs00083

This connects to the virtualization host where the VM must be created.

All subsequent commands must be executed on this host.

Step 2: Verify that virtualization tools are available.

Check the virt-install utility:

virt-install --version

Check the virsh utility:

virsh --version

Also check the QEMU image-management utility:

qemu-img --version

These tools serve different purposes:

virt-install creates and configures virtual machines.

virsh manages and inspects virtual machines through libvirt.

qemu-img examines and manages virtual disk images.

The task states that libvirt must be used, so creating the VM directly with a standalone qemu-system command would not be the appropriate solution.

Step 3: Verify connectivity to the libvirt hypervisor.

Execute:

sudo virsh --connect qemu:///system list --all

virsh communicates with the libvirt virtualization manager.

--connect qemu:///system selects the system-wide QEMU/KVM connection.

list --all displays both running and stopped virtual machines.

An illustrative result is:

Id Name State

--------------------------------

1 existing-vm running

- test-vm shut off

The actual VM list will depend on the host.

If libvirt cannot be contacted, check the host's libvirt services and sockets:

sudo systemctl status libvirtd

Some systems use modular libvirt daemons such as virtqemud, so inspect the installed service arrangement rather than assuming libvirtd is always present.

Step 4: Check whether cool-moray already exists.

Execute:

sudo virsh --connect qemu:///system list --all

Look for a virtual machine named:

cool-moray

You can check directly:

sudo virsh --connect qemu:///system dominfo cool-moray

If libvirt reports that the domain does not exist, proceed.

If the domain already exists, inspect it before making changes. Do not delete or recreate an existing machine without establishing why it is present.

The --name option of virt-install requires a name unique to the target libvirt connection.

Step 5: Verify that the existing disk image is present.

The task specifies the exact disk image path:

/vms/cool-moray/jammy-server-cloudimg-amd64.img

Execute:

ls -lh /vms/cool-moray/jammy-server-cloudimg-amd64.img

If normal user permissions do not allow inspection:

sudo ls -lh /vms/cool-moray/jammy-server-cloudimg-amd64.img

The image must exist before creating the VM.

Do not create an empty virtual disk in its place. The requirement is to use the existing disk image.

Step 6: Inspect the existing virtual disk image.

Execute:

sudo qemu-img info /vms/cool-moray/jammy-server-cloudimg-amd64.img

An example of the resulting information is:

image: /vms/cool-moray/jammy-server-cloudimg-amd64.img

file format: qcow2

virtual size: 2 GiB

disk size: 650 MiB

These size values are illustrative.

qemu-img info identifies the image's format, virtual size, actual allocated storage, and any backing image relationship.

Ubuntu cloud images commonly use QCOW2, but verify the actual image format instead of assuming it from the .img extension.

The existing image must remain intact.

Step 7: Confirm the guest operating-system type.

The disk filename contains:

jammy-server-cloudimg-amd64.img

jammy refers to Ubuntu 22.04 LTS, and amd64 indicates the x86-64 architecture.

Check the installed OS profiles:

virt-install --osinfo list

To find Ubuntu 22.04 specifically:

virt-install --osinfo list | grep -i ubuntu22

If ubuntu22.04 is available, it can be selected using:

--osinfo ubuntu22.04

This provides appropriate guest operating-system metadata and configuration defaults.

If that profile is unavailable, the upstream Ubuntu cloud-image procedure supports using:

--osinfo generic

Do not install a new operating system or download a different disk image merely to complete the task.

Step 8: Create the virtual machine using virt-install.

Once the disk exists, the libvirt connection works and the Ubuntu profile is supported, execute:

sudo virt-install \

--connect qemu:///system \

--name cool-moray \

--memory 1024 \

--disk path=/vms/cool-moray/jammy-server-cloudimg-amd64.img \

--osinfo ubuntu22.04 \

--import \

--noautoconsole

This is the principal solution.

If ubuntu22.04 is not recognized by the installed libosinfo database, substitute --osinfo generic, following the official Ubuntu cloud-image instructions.

The command leaves CPU count, network configuration and other parameters at their supported defaults because the visible task does not prescribe specific values for them.

Step 9: Understand every parameter in the command.

Parameter

Explanation

sudo

Executes with administrative privileges

virt-install

Creates and defines a VM through libvirt

--connect qemu:///system

Targets the system-wide QEMU/KVM hypervisor

--name cool-moray

Assigns the required VM name

--memory 1024

Allocates 1024 MiB of guest memory

--disk path=...

Attaches the existing virtual disk image

--osinfo ubuntu22.04

Selects the Ubuntu 22.04 operating-system profile

--import

Boots an existing OS image without running an installer

--noautoconsole

Prevents automatic attachment to the guest console and allows the command to return

Three arguments are especially important.

--memory 1024

The task specifies memory of 1024 MB. The virt-install utility interprets this parameter in MiB.

Therefore:

--memory 1024

sets the guest's configured RAM to 1024 MiB, equivalent to 1 GiB.

--import

This tells virt-install to create the VM around an existing disk image and skip the operating-system installation process.

Without an appropriate installation method such as --import, virt-install may expect installation media or fail to determine how the guest should be created.

--noautoconsole

The task explicitly requires this flag.

It prevents virt-install from automatically connecting to the guest's graphical or text console. Official documentation states that it also allows virt-install to exit promptly rather than waiting on an interactive console session.

Step 10: Verify that the creation command succeeds.

When virt-install succeeds, it normally prints messages indicating that the VM has been created and the domain is being started.

An illustrative successful message could be:

Starting install...

Creating domain...

Domain creation completed.

Do not treat these example messages as an actual result from the video.

Immediately after the command completes, check the exit status:

echo $?

Expected successful exit status:

0

If the command fails, read the actual error before attempting it again.

Common failure conditions include an existing VM name, inaccessible image path, unsupported OS profile, missing virtualization support or an unavailable default network.

Step 11: Verify that the new virtual machine is registered.

Execute:

sudo virsh --connect qemu:///system list --all

The output should now contain:

cool-moray

For example:

Id Name State

---------------------------

2 cool-moray running

The domain ID and runtime state may differ.

This command verifies that libvirt recognizes the VM.

Step 12: Verify the virtual machine's assigned memory.

Execute:

sudo virsh --connect qemu:///system dominfo cool-moray

Inspect the memory information.

For a VM configured with 1024 MiB, an expected value is:

Max memory: 1048576 KiB

Calculation:

\[ 1024 \times 1024 = 1,048,576 \text{ KiB} \]

This confirms that libvirt has the required memory allocation.

Also verify the VM name and general status in the same output.

Step 13: Verify the attached virtual disk.

Execute:

sudo virsh --connect qemu:///system domblklist cool-moray --details

The output should identify a disk whose source is:

/vms/cool-moray/jammy-server-cloudimg-amd64.img

This verifies that the VM uses the exact existing image required by the task.

Do not confuse creating a new blank disk with attaching the existing disk. The latter is required.

Step 14: Inspect the VM's persistent configuration.

Execute:

sudo virsh --connect qemu:///system dumpxml cool-moray

This displays the libvirt domain definition in XML format.

Look for the guest name:

< name > cool-moray < /name >

Also inspect the memory setting and the disk source.

The relevant configuration should contain the equivalent of:

< memory unit='KiB' > 1048576 < /memory >

And a disk source referencing:

< source file='/vms/cool-moray/jammy-server-cloudimg-amd64.img'/ >

The actual XML may include additional attributes, devices, generated addresses and machine-specific settings.

Step 15: Verify the VM's runtime state.

Execute:

sudo virsh --connect qemu:///system domstate cool-moray

A successful initial launch should normally report:

running

If it reports shut off, investigate the reason:

sudo virsh --connect qemu:///system dominfo cool-moray

You can also inspect the appropriate libvirt/QEMU logs.

Importing a cloud image registers and starts a guest, but it does not automatically establish guest login credentials or configure cloud-init user data. Those operations are not requested by this task.

Step 16: Verify that virt-install has returned control to the terminal.

Because --noautoconsole was specified, the virt-install command should return to the shell after initiating VM creation.

For example, the terminal prompt should become available again:

candidate@lfcs00083:~$

The presence of the normal shell prompt indicates that the creation utility is no longer occupying the terminal.

This is separate from the VM's own runtime state: the virtual machine may continue running after virt-install exits.

Step 17: Perform final verification.

Execute:

sudo virsh --connect qemu:///system list --all

sudo virsh --connect qemu:///system dominfo cool-moray

sudo virsh --connect qemu:///system domblklist cool-moray --details

sudo virsh --connect qemu:///system domstate cool-moray

Confirm the following:

Requirement

Expected result

VM name

cool-moray

Existing disk image

/vms/cool-moray/jammy-server-cloudimg-amd64.img

Memory

1024 MiB

Installation method

Existing image imported

Mandatory option

--noautoconsole used

VM registration

Present in libvirt

VM initial startup

Successful

Terminal

Returns to shell after creation

Final Solution

The essential commands are:

# Connect to the designated server

ssh lfcs00083

# Verify the existing disk image

ls -lh /vms/cool-moray/jammy-server-cloudimg-amd64.img

# Inspect the image

sudo qemu-img info /vms/cool-moray/jammy-server-cloudimg-amd64.img

# Check the VM name is available

sudo virsh --connect qemu:///system list --all

# Confirm the guest OS profile exists

virt-install --osinfo list

# Create the VM

sudo virt-install \

--connect qemu:///system \

--name cool-moray \

--memory 1024 \

--disk path=/vms/cool-moray/jammy-server-cloudimg-amd64.img \

--osinfo ubuntu22.04 \

--import \

--noautoconsole

# Verify the new VM

sudo virsh --connect qemu:///system list --all

sudo virsh --connect qemu:///system dominfo cool-moray

sudo virsh --connect qemu:///system domblklist cool-moray --details

sudo virsh --connect qemu:///system domstate cool-moray

Technical Verification and References

The solution is based on the official virt-install, libvirt and Ubuntu cloud-image documentation.

Ubuntu virt-install(1) Manual — Describes the --memory, --disk, --import, --osinfo and --noautoconsole options.

libvirt virsh Command Reference — Documents VM inspection commands, including list, dominfo, domblklist and domstate.

Ubuntu — Launch QCOW Cloud Images Using libvirt — Provides a practical example of launching an existing Ubuntu cloud image with virt-install, --import and --noautoconsole.

Video verification finding: At approximately 28:30, the recording shows Question 7 and the required host lfcs00083. The candidate begins entering the SSH command but cancels it and moves to Question 8. The recording therefore does not demonstrate a successful VM creation. The solution above is independently documentation-validated, not confirmed as executed in that recording.

Expected result: A virtual machine named cool-moray is created and registered through libvirt using the existing Ubuntu image, with 1024 MiB RAM. The VM starts successfully, and virt-install exits without attaching to the VM's console.

Objective: Configure, compile, and install the GNU software package already extracted into ~/bool, using its default build and installation settings.

The standard GNU build procedure consists of three main commands, executed in this exact order:

/configure

make

sudo make install

The official GNU Autoconf and Automake documentation confirms this sequence for packages using the GNU build system.

Step 1: Connect to the correct Linux server.

The task is associated with host lfcs00102.

From the candidate terminal, execute:

ssh lfcs00102

This establishes an SSH session with the server where the source-code package must be configured, compiled, and installed.

All subsequent commands must be executed on this host.

Step 2: Navigate to the software source directory.

Execute:

cd ~/bool

cd changes the working directory.

~ represents the current user's home directory.

bool is the directory containing the extracted software source code.

Verify the current directory:

pwd

Expected structure:

/home/candidate/bool

The actual home directory depends on the account used on the host.

Step 3: Inspect the extracted source files.

Execute:

ls -la

A GNU Autotools-based source package commonly contains files such as:

configure

Makefile.am

Makefile.in

configure.ac

README

INSTALL

src/

These are examples of commonly encountered files; the actual directory contents may differ.

The critical file for the first stage is:

configure

The task explicitly states that the package has already been unpacked and the required development tools are installed.

Therefore, there is no need to download another source archive, extract additional files, or install development packages.

Step 4: Verify that the configuration script exists.

Execute:

ls -l ./configure

Then check whether it is executable:

test -x ./configure

echo $?

Expected exit code:

0

If the file is readable but lacks execution permission, you can inspect its permissions:

stat -c '%A %a %n' ./configure

Before changing permissions, confirm that the file is the actual generated configuration script.

If necessary, a readable configure shell script can also be executed with:

sh ./configure

However, the normal and preferred invocation for this task is ./configure.

Step 5: Configure the software package using all default settings.

Execute:

/configure

This is the first essential command.

The configure script examines the system and prepares the source tree for compilation.

Typical checks include:

Operating system and processor architecture.

Available C compiler.

Compiler capabilities and flags.

Required libraries and header files.

Build utilities and dependencies.

Installation directory configuration.

Generation of Makefiles.

An illustrative output might include:

checking for gcc... gcc

checking whether the C compiler works... yes

checking for stdio.h... yes

checking for stdlib.h... yes

checking for make... make

configure: creating ./config.status

config.status: creating Makefile

The output will differ according to the source package.

Important: The task requires all default settings. Therefore, do not specify configuration arguments such as:

/configure --prefix=/opt/bool

or:

/configure --disable-shared

unless explicitly requested.

Using plain ./configure ensures that the package's own default configuration options are selected.

GNU Autoconf documents that the default installation prefix is commonly /usr/local, although packages can choose another default.

Step 6: Verify that configuration completed successfully.

Immediately after ./configure finishes, execute:

echo $?

Expected:

0

Exit status 0 indicates that the configuration script completed successfully.

Next, verify the generated Makefile:

ls -l Makefile

You can also check for the configuration status file:

ls -l config.status

For a standard Autoconf package, these files indicate that configuration generated the instructions required for compilation.

If configuration reports a missing dependency or another error, investigate that specific error before proceeding to the build stage.

Do not assume that configuration succeeded merely because some files were generated.

Step 7: Inspect the generated Makefile.

Execute:

ls -lh Makefile

The Makefile contains the instructions that GNU Make uses to build and install the software.

You can inspect the default installation prefix:

grep -E '^prefix[[:space:]]*=' Makefile

A typical result is:

prefix = /usr/local

This means that the package is configured to install files under /usr/local, unless it defines different destinations.

Common GNU installation directories include:

Directory

Typical purpose

/usr/local/bin

User executables

/usr/local/sbin

Administration executables

/usr/local/lib

Program libraries

/usr/local/include

Header files

/usr/local/share

Architecture-independent data

Do not modify the installation prefix because the task requires the default settings.

Step 8: Build the software package.

Execute the second essential command:

make

This instructs GNU Make to build the software using the generated Makefile.

During compilation, Make may perform operations such as:

Reading the Makefile.

Identifying source files and dependencies.

Invoking the compiler.

Compiling source files into object files.

Linking object files with required libraries.

Producing executable programs or library files.

For a package written in C, an illustrative compilation sequence may look like:

gcc -DHAVE_CONFIG_H -I. -c main.c -o main.o

gcc -DHAVE_CONFIG_H -I. -c util.c -o util.o

gcc -o program main.o util.o

These commands are examples. The actual compilation operations depend on the package.

GNU Make normally builds the default target when invoked without arguments. For standard GNU packages, this is equivalent to the all target.

Step 9: Understand why make should normally run without sudo.

The recommended command is:

make

Not:

sudo make

Building as the normal user is preferable because it avoids creating root-owned intermediate files inside the source directory.

Administrative privileges are generally necessary only when installing files into protected system directories.

Since the task states that all build dependencies are already installed, the compilation should not require additional package installation.

Step 10: Verify that compilation completed successfully.

Immediately after make finishes, execute:

echo $?

Expected output:

0

This confirms that the Make process returned a successful exit status.

If compilation fails, the terminal normally reports an error, such as:

make: *** [Makefile:150: all] Error 2

Such output indicates a failed build.

Investigate the preceding compiler or linker error before continuing.

Do not attempt to install a package that has not built successfully.

Step 11: Confirm the build target is up to date.

You can run:

make

again after a successful build.

If no source files have changed, Make may display:

make: Nothing to be done for 'all'.

Alternatively, it may run a small number of checks or other build commands.

This is expected behavior: Make determines which targets need rebuilding based on its rules and dependencies.

A second build is optional and does not replace checking the first command's exit status.

Step 12: Run the package tests if supported.

Many GNU software packages provide an optional test target:

make check

This runs tests defined by the package's build system.

The official GNU Automake documentation defines make check as the conventional test-suite target.

However, the task does not explicitly require running tests.

Therefore, this step is optional. Use it only if the package provides the target and running the tests is appropriate.

If tests are run, verify their outcome:

echo $?

Expected successful status:

0

Do not confuse make check with make install. Tests validate a build but do not necessarily install it.

Step 13: Install the compiled software package.

After a successful build, execute:

sudo make install

This is the third essential command.

sudo provides administrative privileges.

make executes the build system's specified target.

install invokes the Makefile's installation rules.

The command installs the compiled software into its configured destinations.

Depending on the package, installation may include:

Copying executable binaries.

Installing shared or static libraries.

Installing header files.

Installing documentation and manual pages.

Installing additional package data.

The installation location follows the settings selected during ./configure.

GNU Automake confirms that make install copies the required built files into their installation directories.

Step 14: Do not change the installation destination.

The task specifically requests the default configuration.

Therefore, avoid commands such as:

sudo make install prefix=/opt/custom

Also avoid reconfiguring the package using:

/configure --prefix=/opt/custom

These would change the normal installation destinations.

The appropriate installation command remains:

sudo make install

Step 15: Verify that installation completed successfully.

Immediately after sudo make install finishes, execute:

echo $?

Expected:

0

A zero exit code indicates that the installation target completed successfully.

If installation fails with a permissions error, verify whether administrative privileges were applied correctly and inspect the affected directory.

If a build or dependency error occurs during installation, resolve that error before treating the task as complete.

Step 16: Verify the installation destination.

Inspect the installation prefix recorded in the Makefile:

grep -E '^prefix[[:space:]]*=' Makefile

If the prefix is /usr/local, the installed files will typically be placed in appropriate directories beneath that prefix.

You can inspect standard executable locations:

ls -lt /usr/local/bin/

And, where appropriate:

ls -lt /usr/local/lib/

These commands can help identify newly installed files, but they are not conclusive on their own because other software may already exist in those directories.

For more precise verification, inspect the package's Makefile installation rules or any installation manifest it produces.

Step 17: Verify the installed executable if applicable.

If the package installs an executable, first determine its actual command name from the package's documentation or installation output.

Then execute:

command -v ACTUAL_EXECUTABLE_NAME

For example, if a package installs an executable called example-program:

command -v example-program

You can then check its version if that option is supported:

example-program --version

These commands are illustrative. The directory name bool does not prove that the installed executable is also named bool.

Do not invent an executable name when validating the installation.

Step 18: Run installation checks if the package supports them.

Some GNU packages provide the following target:

make installcheck

This runs checks against installed software rather than files within the build tree.

GNU Automake documents installcheck as an optional target for validating installed programs and libraries.

It is not mandatory for this question.

The task requires configuration, compilation and installation. A successful sudo make install operation satisfies the installation stage.

Step 19: Understand why the three commands must be executed in order.

Order

Command

Purpose

1

/configure

Detects the build environment and prepares Makefiles using default settings

2

make

Compiles and links the source code

3

sudo make install

Installs the built software into the configured system directories

Each stage depends on the preceding stage.

Running make before a successful configuration might fail because the necessary Makefile has not been generated.

Running make install without a successful build may also fail or cause the installation target to attempt compilation. That does not replace the explicitly required build step.

For the LFCS simulation, execute each required stage separately and verify success before continuing.

Step 20: Perform the final verification.

From the source directory:

cd ~/bool

Check the generated Makefile:

test -f Makefile & & echo "Makefile exists"

Check the configuration status file if the package uses Autoconf:

test -f config.status & & echo "Configuration completed"

Confirm the configured prefix:

grep -E '^prefix[[:space:]]*=' Makefile

Check that the build is up to date:

make

Finally, verify the installed files or executable using the actual package name and installation output.

A successful result must satisfy all requirements:

Requirement

Expected result

Correct host

lfcs00102

Source directory

~/bool

Configure with defaults

Successful

Build package

Successful

Install package

Successful

Custom configure options

None

Source extraction

Already completed

Dependency installation

Already completed

Final Solution

The complete essential command sequence is:

Copy commands

# Connect to the designated host

ssh lfcs00102

# Navigate to the extracted source package

cd ~/bool

# Inspect the source files

ls -la

ls -l ./configure

# Step 1: Configure with default settings

/configure

# Step 2: Build the software package

make

# Step 3: Install the built package

sudo make install

To verify the exit status of each stage reliably, use the following alternative, which stops if a required stage fails:

cd ~/bool || exit 1

/configure & &

make & &

sudo make install

This short sequence is appropriate when the provided tools and dependencies are already available, as specified in the task.

Technical Verification and References

The solution has been validated against the official GNU build-system documentation.

GNU Autoconf Manual — Explains the generated configure script and default configuration settings.

GNU Make Manual — Explains compilation using Makefiles and Make targets.

GNU Automake — Standard Targets — Documents make, make check, make install and make installcheck.

Expected result: The GNU software package located at ~/bool is successfully configured using its default settings, compiled using GNU Make, and installed through its Makefile's installation target.

Verification limitation: The prescribed sequence is supported by official GNU documentation. Whether the commands successfully complete on lfcs00102 must be confirmed from their actual terminal output and exit statuses; the supplied recording does not establish an independently tested successful installation.