Glossary · Phase 7 · Software engineering
Exit code
The number a program hands back when it ends: 0 for success, anything else for a kind of failure.
A referee's whistle tells everyone what happened without a speech. Every program that ends hands back a number, its exit code. 0 means success and anything else means failure. Shells, scripts and CI read it:
tasks done 9 && echo okprints "ok" only if the command succeeded. Agents read it too, to learn whether a tool call worked.
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Follow these rules and your tool works with every other command-line program.
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Capstone: a command-line app · Design, build and test a complete program with a database. About 45 minutes.
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