Firecracker microVM live per-test verdicts multi-file compile
AWK is the Unix pattern-action language that outlived a hundred replacements because it is small, sharp, and always installed. Sum a column, extract fields, reshape logs — often faster to write awk than to open a proper editor.
ls-judge runs GNU Awk (gawk) 5 in an isolated microVM. Pipe stdin fixtures in from the test panel and watch the transformed output stream back per test case.
Starter code
What you get in AWK
Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.
awkAWK 5
{ print $1 * 2 }
stdin →21
expected →42
++++
FAQ
Common questions about AWK on ls-judge
Which AWK implementation runs here?
GNU Awk (gawk) 5 — the most featureful of the AWKs, including CSV extensions and true multi-file input.
Can I read from stdin?
Yes. The Test panel's "stdin" field feeds directly into the awk process the same way a shell pipeline would.
Does the sandbox allow shell-out (system())?
No — the microVM has no external shell tools reachable. Pure text processing only.
Is a Free tier available?
Yes. Anonymous users get 10 requests/minute; free registered accounts get 30/minute. No credit card.