README.md: small update

Signed-off-by: Vincent Demeester <[email protected]>

README.md

@@ -5,7 +5,11 @@
 [Buildkit](https://github.com/moby/buildkit) frontend to run
 [Tekton](https://tekton.dev) objects locally.
 
-## Usage
+This repository produces two *artifacts*:
+- a [Buildkit](https://github.com/moby/buildkit) frontend
+- a `tkn-local` command to easily consume this frontend (in most situation)
+
+## `buildkit-tekton` Usage
 
 ### With Docker (v20.04+ with `DOCKER_BUILDKIT=1`)
 
@@ -31,7 +35,7 @@ No options yet, but there will be a lot.
 There is a [examples](./examples) folder to try things out.
 
 ```bash
-❯ docker build -t foo -f examples/0-taskrun-simple/run.yaml .
+$ docker build -t foo -f examples/0-taskrun-simple/run.yaml .
 [+] Building 1.6s (12/12) FINISHED
  => [internal] load build definition from run.yaml                                0.0s
  => => transferring dockerfile: 887B                                              0.0s
@@ -51,10 +55,33 @@ There is a [examples](./examples) folder to try things out.
  => exporting to image                                                            0.0s
  => => exporting layers                                                           0.0s
  => => writing image sha256:2ff10579bf3e33cf7cda836d8bdd5962f77d9c995fd342bf3b9e  0.0s
- => => naming to docker.io/library/foo                                            0.0s```
+ => => naming to docker.io/library/foo
+ 0.0s
+ ```
 
 The same `PipelineRun` on `buildkit-tekton` and in a kubernetes
 cluster with tekton installed (both without pre-cached images, … and
 with approximately the same hardware)
 - `buildkit-tekton`: 4m5s
 - `tekton` in `k8s`: 7m
+
+## `tkn-local` Usage
+
+```bash
+$ tkn local
+Local commands
+
+Usage:
+  local [command]
+
+Available Commands:
+  completion  Generate the autocompletion script for the specified shell
+  help        Help about any command
+  prune       Run a tekton resource
+  run         Run a tekton resource
+
+Flags:
+  -h, --help   help for local
+
+Use "local [command] --help" for more information about a command.
+```