diff --git a/README.adoc b/README.adoc
index fedf517..b7b10ce 100644
--- a/README.adoc
+++ b/README.adoc
@@ -11,7 +11,7 @@
 
 == Usage
 
-[source,]
+[source,shell]
 --------------------------------------------------------------------------------
 git show --color=always HEAD | highlight-diffpatch
 git config --global core.pager "diff-highlight | highlight-diffpatch | less --tabs=4 -RFX"