docs(README): add example

README.md

@@ -6,5 +6,19 @@ This project contains all sources to build the container image `git.cryptic.syst
 of this project is to package the binary `jq` as container image. The source code of the binary can be found in the
 upstream project of [adrienverge](https://github.com/adrienverge/jq).
 
-The workflow or how `jq` can in general be used is documented
-[here](https://jq.readthedocs.io/en/stable/).
+The workflow or how `jq` can in general be used is documented [here](https://jq.readthedocs.io/en/stable/). An example
+how to use this image and read a JSON file from stdin is documented below. Pleas adapt the path of the JSON file.
+
+```bash
+# read file (stdin)
+docker run \
+  --interactive \
+  --rm \
+    git.cryptic.systems/volker.raschek/jq:latest < /etc/docker/daemon.json
+
+# cat (stdin)
+cat /etc/docker/daemon.json | docker run \
+  --interactive \
+  --rm \
+    git.cryptic.systems/volker.raschek/jq:latest
+```