Associative Arrays in Bash

From the Bash Scripting cheat sheet · Arrays · verified Jul 2026

Key-value maps (bash 4+).

bash

# Quick Reference
declare -A ages
ages[sam]=30
echo "${ages[sam]}"       # 30
echo "${!ages[@]}"        # keys

💡 Associative arrays require declare -A first - otherwise keys are treated as 0.

⚡ ${!map[@]} gives keys; ${map[@]} gives values; ${#map[@]} gives the count.

📌 Associative arrays need bash 4+ (macOS ships bash 3.2 - install a newer bash).

🟢 [[ -v map[key] ]] tests whether a key exists without inserting it.

arraysassociative

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