XK0-006 Practice Test 25 — 15 Questions

Question 1

A Linux administrator is writing a bash script that needs to iterate over all files ending with .log in /var/log and output the number of lines in each file. Which loop construct should be used?

Accepted Answer

for f in /var/log/*.log; do wc -l "$f"; done. A for loop with a glob pattern is the simplest way to iterate over files matching a pattern.

Answer

while read f; do wc -l "$f"; done < /var/log/*.log

Answer

for ((i=0; i<${#files[@]}; i++)); do wc -l "${files[$i]}"; done

Answer

until [ -z "$f" ]; do wc -l "$f"; shift; done

Question 2

In a bash script, a developer needs to parse command-line options such as -f filename and -v (verbose). Which built-in command is best suited for this task?

Accepted Answer

getopts. getopts is a bash built-in for parsing command-line options. It handles short options and requires option arguments.

Answer

getopt

Answer

case

Answer

shift

Question 3

In a Bash script, the following array is defined: fruits=('apple' 'banana' 'cherry'). Which syntax correctly iterates over all elements of the array?

Accepted Answer

for fruit in "${fruits[@]}"; do echo $fruit; done. To iterate over all elements of an array, use for fruit in "${fruits[@]}"; do ... done. The [@] syntax expands to all elements.

Answer

for fruit in "${fruits[*]}"; do echo $fruit; done

Answer

for fruit in ${fruits[@]}; do echo $fruit; done

Answer

for fruit in ${fruits}; do echo $fruit; done

Question 4

In a bash script, a function is defined to calculate a value. Which TWO of the following are valid ways to return a value from the function to the caller? (Select TWO).

Accepted Answer

echo 42. The return statement sets the exit status (0-255). echo outputs to stdout which can be captured via command substitution. Functions cannot return arbitrary integers directly via return if >255.

Answer

exit 42

Answer

return 'value'

Answer

print 42

Question 5

A system administrator is configuring PAM to lock out users after 3 failed login attempts for 15 minutes. Which TWO PAM modules can be used together to achieve this? (Select TWO.)

Accepted Answer

pam_faillock.so. pam_faillock.so is the modern PAM module designed to track failed login attempts and enforce account lockout policies. It can be configured with parameters like `deny=3` to lock after three failures and `unlock_time=900` to set a 15-minute lockout duration. This module is the recommended replacement for the deprecated pam_tally2.so in current Linux distributions.

Answer

pam_tally2.so

Answer

pam_limits.so

Answer

pam_pwquality.so

Question 6

A developer is writing a Dockerfile. The application requires a configuration file that should be copied from the build context and the container should expose port 8080. Which combination of Dockerfile instructions is correct?

Accepted Answer

COPY config.txt /app/ and EXPOSE 8080. COPY adds files from the build context, and EXPOSE documents the port. Other instructions serve different purposes.

Answer

ADD config.txt /app/ and WORKDIR 8080

Answer

ADD config.txt /app/ and RUN expose 8080

Answer

COPY config.txt /app/ and CMD 8080

Question 7

A system administrator needs to update a configuration file on multiple servers using Ansible. The playbook must ensure the line 'MaxAuthTries 3' is present in /etc/ssh/sshd_config. Which Ansible module is most appropriate?

Accepted Answer

lineinfile. The lineinfile module ensures a specific line is present in a file, ideal for configuration management.

Answer

template

Answer

shell

Answer

copy

Question 8

A Linux administrator is writing a Bash script that must handle errors gracefully. Which TWO of the following techniques ensure the script exits on error and provides debugging information? (Select TWO.)

Accepted Answer

set -x. set -e makes the script exit on any command failure. set -x prints commands as they are executed, aiding debugging. Together they ensure error exit and debugging output.

Answer

set -u

Answer

trap 'echo error' ERR

Answer

set -o pipefail

Question 9

An Ansible playbook is being written to install the Nginx web server on a group of Ubuntu servers. Which module should be used in the playbook to install the package?

Accepted Answer

apt. The apt module is used for package management on Debian/Ubuntu systems.

Answer

command

Answer

package

Answer

yum

Question 10

A containerized application uses a bind mount to persist logs. When the container is removed and recreated, the logs are missing. What is the most likely cause?

Accepted Answer

The bind mount was not specified in the new container run command. Bind mounts depend on the host path; if the bind mount was not re-specified, the new container does not have access to the previous host directory unless explicitly mounted.

Answer

The container was run with --rm, which deletes the bind mount

Answer

The host directory was deleted when the container was removed

Answer

The log files were written to the container's writable layer instead of the mount

Question 11

A developer is writing a Bash script that needs to parse command-line options with arguments, such as -f filename and -v. Which built-in command should be used to handle these options?

Accepted Answer

getopts. getopts is the standard Bash built-in for parsing short options with or without arguments.

Answer

getopt

Answer

case

Answer

shift

Question 12

Which Dockerfile instruction sets the command to run when the container starts, but allows the user to override it when using docker run?

Accepted Answer

CMD. CMD provides defaults for an executing container. If CMD is used, it can be overridden by command-line arguments to docker run. ENTRYPOINT, on the other hand, is not easily overridden without --entrypoint.

Answer

RUN

Answer

STARTUP

Answer

ENTRYPOINT

Question 13

Which Kubernetes resource is used to store non-sensitive configuration data as key-value pairs that can be consumed by pods?

Accepted Answer

ConfigMap. ConfigMaps are used for non-sensitive configuration data. Secrets are for sensitive data like passwords. Deployments manage replicas of pods. Namespaces isolate resources.

Answer

Deployment

Answer

Secret

Answer

Namespace

Question 14

An Ansible playbook is being written to manage web servers. Which TWO modules can be used to ensure a package is installed? (Select TWO.)

Accepted Answer

apt. The apt module is for Debian-based systems, and yum is for Red Hat-based systems. Both manage packages.

Answer

copy

Answer

service

Answer

template

Question 15

A bash script needs to test whether a string variable $NAME is non-empty and equals 'admin'. Which of the following conditionals is correct?

Accepted Answer

if [[ -n $NAME && $NAME == 'admin' ]]; then. In bash, [[ -n $NAME ]] tests if the string is non-empty, and == compares strings. Using double brackets is safer for string comparison.

Answer

if [[ $NAME -ne '' && $NAME -eq 'admin' ]]; then

Answer

if [ $NAME != '' ] && [ $NAME == 'admin' ]; then

Answer

if [ ! -z $NAME -a $NAME = 'admin' ]; then