Add doc for BUILDKIT_PROGRESS env var
@@ -78,6 +78,7 @@ line:
| `DOCKER_HOST` | Daemon socket to connect to. |
| `DOCKER_STACK_ORCHESTRATOR` | Configure the default orchestrator to use when using `docker stack` management commands. |
| `DOCKER_TLS_VERIFY` | When set Docker uses TLS and verifies the remote. This variable is used both by the `docker` CLI and the [`dockerd` daemon](dockerd.md) |
+| `BUILDKIT_PROGRESS` | Set type of progress output (`auto`, `plain`, `tty`) when [building](build.md) with [BuildKit backend](../builder.md#buildkit). Use plain to show container output (default `auto`). |
Because Docker is developed using Go, you can also use any environment
variables used by the Go runtime. In particular, you may find these useful:
