awk

Advanced~35 min read

awk is a small language for scanning and processing text with fields and patterns. It shines at CSV/TSV and report generation.

Basics: Fields and Filters

Output

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Output

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Note: Set the field separator with -F or inside a BEGIN block.

Pro Tip: Use printf for aligned columns and reports.

Caution: Beware of CSV corner cases (quoted commas). Consider dedicated CSV tools when needed.

When processing CSV with headers, include a condition to skip the first line.

Ensure the field separator matches your data (e.g., comma vs tab).

Task: From name,age,city CSV on stdin, print the average age per city.

Output

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Show Solution

awk -F, 'NR>1 { sum[$3]+=$2; count[$3]++ } END{ for(c in sum) printf "%s %.2f\n", c, sum[c]/count[c] }'

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