XK0-006 Practice Test 24 — 15 Questions

Question 1

A security audit reveals that the /etc/shadow file is readable by all users. What is the most appropriate immediate action?

Accepted Answer

chmod 600 /etc/shadow && chown root:shadow /etc/shadow. The /etc/shadow file stores hashed user passwords and must be protected from unauthorized access. The correct command is `chmod 600 /etc/shadow && chown root:shadow /etc/shadow` because it sets the file to be readable and writable only by the owner (root) and changes the group to 'shadow', which is the standard group used by many Linux distributions to allow certain system utilities (like `pwck` or `unix_chkpwd`) to read the file without granting access to all users. This ensures that only root and members of the shadow group can read the file, immediately fixing the security issue.

Answer

chmod 000 /etc/shadow

Answer

chmod 640 /etc/shadow

Answer

chmod 600 /etc/shadow

Question 2

A Linux administrator is writing a Bash script that must accept command-line options for an input file (-i) and an output file (-o). Which of the following are valid methods to parse these options? (Choose TWO.)

Accepted Answer

Using the getopt command. getopts is a built-in for parsing options, and getopt is an external command. Both can be used.

Answer

Using positional parameters $1, $2 directly

Answer

Using a here-document

Answer

Using the shift command only

Question 3

A Bash script contains the following line: set -e. What is the effect of this command?

Accepted Answer

It causes the script to exit if any command fails.. set -e causes the script to exit immediately if any command exits with a non-zero status. This is useful for catching errors early.

Answer

It enables debugging by printing commands and their arguments as they are executed.

Answer

It prevents the script from overwriting existing files.

Answer

It treats unset variables as an error and exits.

Question 4

In bash, what is the difference between single quotes and double quotes?

Accepted Answer

Single quotes prevent variable expansion, double quotes allow it.. Single quotes preserve the literal value of each character, while double quotes allow variable expansion and command substitution.

Answer

Both allow variable expansion, but double quotes also allow globbing.

Answer

Single quotes allow variable expansion, double quotes do not.

Answer

There is no difference; they are interchangeable.

Question 5

An administrator is troubleshooting a Pod in a Kubernetes cluster that is not starting. Which TWO kubectl commands are most useful for diagnosing the issue? (Choose TWO.)

Accepted Answer

kubectl logs <pod-name>. kubectl describe pod provides detailed event and status information, and kubectl logs retrieves container logs.

Answer

kubectl get nodes

Answer

kubectl apply -f pod.yaml

Answer

kubectl delete pod <pod-name>

Question 6

A Docker container is running in the background. Which command allows the administrator to execute an interactive bash shell inside the running container named 'webapp'?

Accepted Answer

docker exec -it webapp bash. docker exec -it runs an interactive command in a running container. The other commands are for different purposes.

Answer

docker start -i webapp

Answer

docker run -it webapp bash

Answer

docker attach webapp

Question 7

A Linux administrator is writing a bash script to process a list of usernames stored in an array. The script must iterate over each username and print a welcome message. Which TWO of the following loops will correctly iterate over the array 'users' and print 'Welcome, <username>'? (Choose TWO.)

Accepted Answer

for ((i=0; i<${#users[@]}; i++)); do echo "Welcome, ${users[$i]}"; done. Arrays can be iterated using for with ${users[@]} or using indices. The correct methods are direct iteration over elements and using a C-style for loop with indices.

Answer

for user in $users; do echo "Welcome, $user"; done

Answer

for user in "${users[*]}"; do echo "Welcome, $user"; done

Answer

while read user; do echo "Welcome, $user"; done < <(printf '%s
' "${users[@]}")

Question 8

A DevOps engineer is writing a Bash script that checks if a file exists and is readable. Which test condition should be used inside an if statement?

Accepted Answer

[[ -r file ]]. The -e test checks if a file exists, and -r checks if it is readable. Using -f also checks for a regular file, but the question requires existence and readability, so combining -e and -r is correct. However, the options include -f and -r, but -f alone does not check readability. The correct combination is -e and -r, but since that is not an option, the best answer is -r because it implies existence? Actually, -r returns true only if the file exists and is readable. So -r alone satisfies both conditions.

Answer

[[ -e file ]]

Answer

[[ -f file ]]

Answer

[[ -s file ]]

Question 9

A Linux administrator is writing a Bash script that uses a function. Which two statements about Bash functions are correct? (Choose TWO.)

Accepted Answer

Functions are called by their name without parentheses.. Bash functions must be defined before use and are called by name without parentheses.

Answer

Function definitions must be placed at the beginning of the script.

Answer

Functions cannot accept arguments.

Answer

Functions can be called before they are defined.

Question 10

In a Kubernetes cluster, a developer needs to create a Deployment that runs three replicas of a container image 'myapp:1.0' and exposes port 8080. Which YAML snippet correctly defines this Deployment?

Accepted Answer

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:1.0
        ports:
        - containerPort: 8080. A Deployment YAML must have apiVersion, kind, metadata, spec with replicas and template containing container spec with image and ports.

Answer

apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  replicas: 3
  containers:
  - name: myapp
    image: myapp:1.0
    ports:
    - containerPort: 8080

Answer

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    app: myapp
  template:
    containers:
    - name: myapp
      image: myapp:1.0
      ports:
      - containerPort: 8080

Answer

apiVersion: v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  template:
    spec:
      containers:
      - name: myapp
        image: myapp:1.0
        ports:
        - containerPort: 8080

Question 11

A Kubernetes YAML manifest defines a Deployment. Which field specifies the number of pod replicas to run?

Accepted Answer

spec.replicas. In a Deployment spec, the 'replicas' field sets the desired number of pod instances.

Answer

metadata.replicas

Answer

spec.template.replicas

Answer

spec.containers.replicas

Question 12

In a Bash script, what is the purpose of the shebang '#!/bin/bash'?

Accepted Answer

It specifies the path to the Bash executable that should run the script.. The shebang tells the system which interpreter to use to execute the script.

Answer

It defines a variable for the Bash version.

Answer

It sets the script's permissions to executable.

Answer

It enables debug mode for the script.

Question 13

A DevOps engineer is writing a Dockerfile. The application requires environment variables to be set at runtime from a file. Which Dockerfile instruction should be used to achieve this?

Accepted Answer

ENV. The ENV instruction sets environment variables in the Dockerfile, but for runtime from a file, the --env-file option is used with docker run. However, within the Dockerfile, ENV is the instruction to set environment variables.

Answer

CMD export

Answer

ARG

Answer

RUN export

Question 14

An administrator is writing a bash script that loops through all .log files in /var/log and prints the file name if the file is larger than 100 kilobytes. Which loop correctly implements this?

Accepted Answer

find /var/log -name '*.log' -size +100k -exec echo {} \;. The find command with -size filters files larger than 100k, and -exec with {} runs the command for each file. The other options have syntax errors or incorrect logic.

Answer

ls -l /var/log/*.log | awk '$5>100 {print $NF}'

Answer

for f in /var/log/*.log; do if [ -s $f -a $(stat -c%s $f) -gt 100 ]; then echo $f; fi; done

Answer

for f in /var/log/*.log; do if [ $f -gt 100k ]; then echo $f; fi; done

Question 15

A system administrator is writing a bash script that must check if a file exists and is readable before processing. Which TWO test expressions can be used in an if statement? (Select TWO.)

Accepted Answer

[ -e /path/to/file ]. The -e test checks existence, and -r checks readability. Other options are for different attributes.

Answer

[ -f /path/to/file ]

Answer

[ -x /path/to/file ]

Answer

[ -s /path/to/file ]