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Linux Operations Skills Quiz ​

This quiz tests your understanding of Linux operations skills used in Kubernetes environments.

Multiple Choice Questions ​

  1. Which command makes environment variables available to child processes?
    • A) set
    • B) export
    • C) declare
    • D) env
Show Answer

Answer: B) export

  1. When is .bashrc executed?
    • A) Only for login shells
    • B) For all shell sessions
    • C) For non-login interactive shells
    • D) Always with .bash_profile
Show Answer

Answer: C) For non-login interactive shells

  1. What does ${REPLICAS:-3} mean?
    • A) Set REPLICAS to 3
    • B) Use 3 if REPLICAS is unset or empty
    • C) Subtract 3 from REPLICAS
    • D) Error
Show Answer

Answer: B) Use 3 if REPLICAS is unset or empty

  1. What does awk 'NR>1 {print $1}' do?
    • A) Print first field of all lines
    • B) Print only the first line
    • C) Print first field excluding header
    • D) Print lines with first field
Show Answer

Answer: C) Print first field excluding header

  1. What is the role of g in sed -i 's/old/new/g'?
    • A) Case insensitive
    • B) Replace all matches in line
    • C) Replace once
    • D) Enable regex
Show Answer

Answer: B) Replace all matches in line

  1. What does -r do in jq -r?
    • A) Recursive search
    • B) Reverse order
    • C) Raw string output without quotes
    • D) Read-only
Show Answer

Answer: C) Raw string output without quotes

  1. What does ssh -L 8080:localhost:80 user@server mean?
    • A) Forward server 8080 to local 80
    • B) Forward local 8080 to server 80
    • C) Forward server 80 to local 8080
    • D) Forward local 80 to server 8080
Show Answer

Answer: B) Forward local 8080 to server 80

  1. What does wa represent in vmstat?
    • A) Web application CPU
    • B) I/O wait time percentage
    • C) Warning count
    • D) Active processes
Show Answer

Answer: B) I/O wait time percentage

  1. Which command creates an LVM Physical Volume?
    • A) lvcreate
    • B) vgcreate
    • C) pvcreate
    • D) fscreate
Show Answer

Answer: C) pvcreate

  1. What does curl -s -o /dev/null -w "%{http_code}" URL output?
    • A) Response body
    • B) Response headers
    • C) HTTP status code
    • D) Response time
Show Answer

Answer: C) HTTP status code

Short Answer Questions ​

  1. What command executes file contents in the current shell?
Show Answer

Answer: source (or .)

  1. What is the JSON parsing tool?
Show Answer

Answer: jq

  1. What SSH option is used for bastion jump?
Show Answer

Answer: ProxyJump (or -J)

  1. What command monitors disk I/O?
Show Answer

Answer: iostat

  1. What is the path to the Pod service account token?
Show Answer

Answer: /var/run/secrets/kubernetes.io/serviceaccount/token

This is the default projected-token path; it may be absent if automount is disabled. Tokens rotate.

Practical Questions ​

  1. Write a script with required DATABASE_URL and TIMEOUT default 30.
Show Answer
bash
#!/bin/bash
: "${DATABASE_URL:?DATABASE_URL required}"
TIMEOUT=${TIMEOUT:-30}
  1. Write a command to output Pods whose regular and init containers have at least 3 combined restarts as JSON.
Show Answer
bash
kubectl get pods -A -o json | jq '[.items[] | select(([(.status.containerStatuses[]?, .status.initContainerStatuses[]?) | .restartCount] | add // 0) >= 3)]'
  1. Write an rsync command to sync yaml files through bastion.
Show Answer
bash
rsync -avzP --prune-empty-dirs --include='*/' --include='*.yaml' --exclude='*' -e "ssh -J bastion" /src/ user@host:/dest/

Advanced Questions ​

  1. Write a node diagnostic script.
Show Answer
bash
#!/bin/bash
echo "=== System ===" && uptime && free -h && df -h
echo "=== kubelet ===" && systemctl status kubelet --no-pager
  1. Explain ConfigMap env vars vs volume mount differences.
Show Answer
  • Environment Variables: Loaded at Pod start, requires restart for changes
  • Volume mount: Updates propagate eventually (kubelet sync period plus cache/watch delay). The application must reread/reload the file. subPath mounts do not receive updates.

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Verification References ​