diff --git a/containerization/docker.md b/containerization/docker.md
index c8e176a..c791ba3 100644
--- a/containerization/docker.md
+++ b/containerization/docker.md
@@ -1 +1,11 @@
 # docker
+
+## Output format
+
+You can change the output format of any (?) docker command to JSON by using the following parameter:
+
+```
+docker ps -a --format '{{json .}}'
+```
+
+It uses the Go templating engine.