helm install myChart-0.0.1.tgz --output json results in Error: unknown flag: --output
I use helm version v2.14.3. According to the docs https://helm.sh/docs/helm/#helm-install this should work. Other flags seem to work fine. E.g. helm install myChart-0.0.1.tgz --namespace test-ns --set random.variable="debug" --name mychart
The documentation also states the schema helm install [CHART] [flags], while its examples suggest the schema helm install [flags] [CHART] in my tests both seem to work but non accepts the output flag.
The output flag was added with commit a52d6de9e17fc4dda4928f0029362e9be075aa24 which is only present in the release-2.15 branch. The documentation is generated from master, so it already has the option, but your version does not yet.
Your current version doesn't support the --output flag, to use it upgrade your helm version to v2.15.0.
From: V2.15.0 Changelog
Introduced --output to helm repo list, helm search, and helm install