Interview › Scripting (Bash, Groovy)
How do you print specific lines of a file with sed or awk? [Advanced]
Answer
With sed, use -n and p to print specific lines or ranges. With awk, use NR conditions. awk is often clearer when line selection depends on numeric conditions or fields.
Technical explanation
sed -n '10,20p' prints lines 10 through 20.
awk 'NR==10' prints a single line; awk 'NR>=10 && NR<=20' prints a range.
For huge files, tools like sed can stop early with q when only early lines are needed.
Hands-on example
sed -n '10,20p' app.log
awk 'NR >= 10 && NR <= 20 {print}' app.log
# Print first match and quit.
sed -n '/ERROR/{p;q;}' app.log
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