CompTIA Linux+ Practice Test (XK0-005)

The correct sequence for compiling software from source code is typically to first run the ./configure script to check system dependencies and create a Makefile. Next, the make command is used to compile the source code into binary files based on the Makefile's instructions. Finally, make install is executed, usually with root privileges, to copy the compiled binaries, libraries, and documentation to their appropriate locations in the filesystem. The other sequences are incorrect as they do not follow this standard workflow.

The nmap command can test connectivity to a specific TCP port on a remote host and report whether that port is open. By specifying the -p option with 80 (the default HTTP port) and the target's IP address, nmap sends the necessary probe packets and interprets the response, confirming both that the service is listening and that the port is reachable. openssl s_client focuses on initiating an SSL/TLS handshake; when pointed at an unencrypted HTTP port it typically hangs or errors, so it is not ideal for simple port-reachability tests. netstat displays sockets on the local system only and cannot interrogate a remote host. dig is used for DNS lookups, not for checking open ports.

Type=notify is used for daemons that call sd_notify() to send a READY=1 message to the systemd notification socket. Systemd will not mark the service active, nor start units that depend on it, until this message is received. Type=simple is considered active immediately after the main process is forked (or execed in the case of Type=exec). Type=forking assumes the service is ready once the parent process exits. Type=dbus waits until the specified D-Bus name is acquired. Only notify relies on an explicit ready signal from the service itself.

According to the Filesystem Hierarchy Standard (FHS), the /home directory is the designated location for user-specific files and directories. When a new user account is created, a subdirectory (e.g., /home/mchavez) is typically generated to serve as that user's personal workspace. The /boot directory contains files essential for the system's boot process. The /etc directory holds system-wide configuration files, not user-specific data. The /tmp directory is intended for temporary files that may be deleted upon reboot.

The legacy shorthand command docker ps lists only containers that are currently running. Adding the -a (or --all) option would include stopped containers, while the docker container ls command is a newer subcommand alias but is not the requested shorthand form. docker container ls -a lists all containers, and the pipeline using docker inspect gathers details for each listed ID rather than displaying the running containers directly.

The numeric mode prefix 1 applies the sticky bit. Mode 1777 grants read, write, and execute access to the owner, group, and others while restricting file deletion and renaming within the directory to the file's owner. Prefix 2 sets the setgid bit (group ID), prefix 6 sets both the setuid and setgid bits, and prefix 0 leaves no special bits, so other users could remove files they don't own.

The pwd command (print working directory) returns the absolute path of the current directory. Capturing its output with command substitution $(pwd) is the standard and most reliable method for this task. The distractor dirname $0 would return the directory containing the script file itself, which is not necessarily the same as the directory it was executed from. which $0 is not a valid use of which, as which locates a command in the user's PATH, it does not operate on script paths this way. The correct shell variable for the current working directory is PWD, not CWD, making EXEC_DIR=$CWD incorrect.

The correct command uses the wget -O option. The -O (short for --output-document) flag writes the downloaded content to a specified file. In this scenario, it saves the patch with the desired descriptive filename vendor_patch_2025-10-07.tar.gz instead of the original, non-descriptive name from the URL. The --output-file option is incorrect because it redirects log messages from wget to a file, rather than saving the downloaded content. The --save-as and --download-as options are not valid for the wget command.

The correct answer is grub2-mkconfig -o /boot/grub/grub.cfg. When the grub2-mkconfig command is followed by -o (output) option, it directs the command to write the generated configuration to a specified file, which is typically /boot/grub/grub.cfg or /boot/grub2/grub.cfg depending on the distribution. Writing to any other location, as suggested in the incorrect answers, will not influence the boot process, and the command update-grub is a convenience script present in some systems, which essentially calls grub-mkconfig with the appropriate arguments.

The sed command is used to perform basic text transformations. In the example provided, 's/quick/slow/' is a substitute command that tells sed to replace the first occurrence of the pattern 'quick' with the replacement 'slow'. The result is the output of the initial string with the word 'quick' replaced by 'slow'.

The correct answer is df -h > /dev/null. The > operator redirects the standard output (STDOUT) to the specified file, in this case, /dev/null. The /dev/null device is a special file that discards all data written to it, effectively silencing any output that would normally be sent to the terminal. Incorrect answers involve the use of 2> /dev/null which would only redirect standard error (STDERR) and &> /dev/null which is not as commonly used or may not be the intended operation since it redirects both STDOUT and STDERR.

Generating an SSH key pair with ssh-keygen and then using ssh-copy-id to append the technician's public key to the server's ~/.ssh/authorized_keys file enables public-key authentication. The private key remains on the technician's workstation, and the SSH daemon grants access only after the technician proves possession of that key, eliminating the need to transmit or store a password on the server. Simply providing the server password continues to rely on weaker, brute-force-susceptible password authentication. Running ssh-add alone merely loads an existing private key into the local ssh-agent and does not install the key on the server. Editing ~/.ssh/config can set host aliases or specify an identity file, but it still requires the public key to be present in authorized_keys to permit passwordless login. Therefore, deploying the key pair with ssh-copy-id is the most secure and complete solution for password-free access.

The Ctrl+Z keyboard shortcut sends the SIGTSTP (Terminal Stop) signal, which suspends the current foreground process. This allows the administrator to regain control of the shell. The suspended process can be resumed later in the foreground with fg or in the background with bg. Ctrl+C sends the SIGINT (Interrupt) signal, which typically terminates a process. The bg command is used to resume an already suspended process in the background. kill -9 <PID> sends the SIGKILL signal, which forcibly and non-gracefully terminates a process.

The correct choice is a Pod. In Kubernetes, a Pod is the smallest deployable unit and can encapsulate one or more tightly coupled containers that share the same network namespace and any mounted volumes, ensuring they always run together. A Service only exposes a stable network endpoint, a Deployment maintains the desired replica count and updates for Pods, and a Namespace serves as a logical cluster partition for resource isolation.

To deactivate a logical volume and make it unavailable to the system, the lvchange -an (or lvchange --activate n) command is used. This prevents the kernel from recognizing the logical volume by removing its device mapper target, which stops all I/O. Making the volume read-only with the -pr option would prevent writes but would not take it offline. The --alloc lock option is not a valid parameter for the lvchange command, as 'lock' is not a defined allocation policy. The lvextend command is used for resizing logical volumes, not for changing their activation state.

The correct action is to generate a self-signed certificate because it allows the administrator to implement encryption for the web service without involving an external certificate authority (CA). This method is suitable for environments where trust is established by other means, such as within an organization where all clients accessing the service are controlled and can be configured to trust the self-signed certificate. The use of a self-signed certificate enables encrypted connections and ensures data privacy on the internal network.

A process that has completed execution but still has an entry in the process table is in the 'zombie' state. This occurs when a process has finished running, but its parent has not yet called wait() to read the child's exit status, leaving an entry in the process table as a 'zombie' that needs to be reaped. This is why the 'zombie' state is also sometimes referred to as a 'defunct' process. The other options are incorrect: 'running' is when a process is actively being executed; 'sleeping' is when a process is waiting for a resource or event; 'stopped' is when a process has been paused, typically by a signal, not when it has finished execution.

The insmod command is used to insert a kernel module directly from a specified file path, without automatically handling dependencies. This makes it ideal for testing or loading modules that are not yet part of the system's managed module tree. The modprobe command, in contrast, is a more sophisticated tool that loads modules by name and automatically resolves and loads their dependencies from standard locations. lsmod is used to list currently loaded modules, and modinfo displays information about a module file, but neither command loads modules. Therefore, for loading a single module file directly, insmod is the correct choice.

Cloud-init is a widely used tool for the early initialization of cloud instances. It supports various cloud platforms and allows for the automatic configuration of the environment based on user-provided initialization metadata, such as setting hostnames, usernames, and network configurations through user-data scripts or configuration files. This makes it excellent for quickly bootstrapping new virtual machines with the necessary custom settings. Other tools like Puppet and Ansible are also used for automation and configuration management, but they are typically used post-boot for ongoing management, rather than during the initial boot process.

The '-A' option in Nmap enables aggressive scanning, which combines OS detection, version detection, script scanning, and traceroute. This thorough scanning option is informative for deep network analysis. The '-sn' option is for ping scanning (host discovery), '-p-' scans all 65535 ports, and '-o' is an invalid option as it lacks the specifics for output files like '-oN' or '-oX'.