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command-substitution
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Question 45. CSCD240-E1-A
Print "Backup taken on <today>" using $(date +%Y-%m-%d) as the date.
Work the drill
Answer on paper or in a terminal before revealing the ideal answer.
Ideal answer
echo "Backup taken on $(date +%Y-%m-%d)"
Acceptable alternatives: ["echo \"Backup taken on `date +%Y-%m-%d`\""]
Misconception bank
Each row below is a plausible wrong answer, the thinking that produces it, and the remedy that corrects the misconception. These are the foundation of the multiple-choice framing and the targeted feedback a student receives after answering.
echo 'Backup taken on $(date +%Y-%m-%d)'
Misconception. Single quotes prevent substitution — prints literal.
Remedy. Double quotes REQUIRED for $() expansion.
echo Backup taken on $(date +%Y-%m-%d)
Misconception. Works but spaces inside echo are fragile; accept.
Remedy. No quotes works here because no multi-word substitutions. But habitually quote.
Authority mappings
Hover any chip for the mapping justification; click to open the authority record.
DCWF roles:
SE-627 DevSecOps Specialist
DCWF tasks:
T0498
KU topics:
CD-BSP-T8a
Course-artifact links
Lectures
- CSCD240-S26-L05. Permissions part 1: ls -l anatomy, rwx, file types
Lab questions
- CSCD240-S26-LAB5: Use $(date +%F) inside a string. Also demonstrate backticks.
CTF challenges
- 04 Environment & Patterns: Capture the Output
- 04 Environment & Patterns: Its a trap