Exit codes

Code	Meaning	Example
0	Success.	The call returned its replies.
1	Failure that fits nowhere else.	The connection broke mid-stream.
2	Usage error: bad flags, arguments, parameters or config.	.id: expected int, got string
3	The service returned a Varlink error.	io.systemd.Resolve.NoNameServers
4	vlx refused the call under its safety policy.	A WRITE method without --allow-writes, or without --yes in a script.
5	The service could not be found or reached.	No socket matches the name; nothing listens on it.
130	Interrupted with Ctrl+C.	A stream stopped by hand.

vlx call demo SetDefaultLanguage '{"language":"german"}'
case $? in
  0) echo done ;;
  4) echo "refused: rerun with --allow-writes" ;;
  *) echo "failed" ;;
esac