Exit Code Reference

Program completed successfully.

Cause: Normal termination.

Catch-all for general errors.

Cause: Most script and application errors.

Misuse of shell built-ins (e.g. missing keyword).

Cause: Invalid flags or missing arguments to shell commands.

Permission denied or binary format error.

Cause: Missing execute permission — run chmod +x file.

The command was not found in PATH.

Cause: Typo, not installed, or not in PATH.

Exit called with a non-integer argument.

Cause: exit 3.14 or exit somevariable (non-numeric).

128+2 — script terminated by keyboard interrupt.

Cause: User pressed Ctrl+C.

128+9 — process killed without cleanup.

Cause: kill -9, OOM killer, or container resource limit.

128+15 — graceful termination requested.

Cause: kill command, systemd stop, Docker stop.

Exit code outside the 0–255 range was used.

Cause: exit -1 or exit 300 — wrapped to 255.

Protocol not supported by curl.

Cause: Unrecognised URL scheme.

The URL could not be parsed.

Cause: Bad URL syntax or illegal characters.

The hostname could not be resolved via DNS.

Cause: DNS failure, no network, or hostname typo.

Could not connect to host or proxy.

Cause: Host down, firewall blocking, or wrong port.

HTTP server returned an error status (4xx/5xx).

Cause: Used with --fail / -f flag.

The operation exceeded the specified timeout.

Cause: Slow server or network issues — try --max-time.

SSL/TLS handshake failed.

Cause: Expired cert, self-signed cert, or version mismatch.

Server closed the connection with no reply.

Cause: Server crashed or closed connection prematurely.

Failure when receiving network data.

Cause: Connection reset mid-transfer.

Unhandled exception with no domain or uncaughtException handler.

Cause: Unhandled throw or unhandled promise rejection.

Fatal error in the V8 engine.

Cause: Out of memory or internal V8 assertion failure.

Unknown or invalid option passed to node.

Cause: Unrecognised flag: node --bad-flag app.js

Debug / inspect port already in use.

Cause: --inspect port conflict.

The docker command itself failed to run.

Cause: Docker daemon not running or bad flag.

Contained command exists but is not executable.

Cause: Wrong architecture or missing permissions inside image.

Command not found inside the container image.

Cause: Tool not installed in the image.