diff --git a/unreleased.sh b/unreleased.sh
index c6d854a2cc..8164129a6e 100755
--- a/unreleased.sh
+++ b/unreleased.sh
@@ -2,6 +2,13 @@
 # Copyright (c) 2019 The DAML Authors. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
+if [ "$#" -ne 1 ]; then
+    echo >&2 "Usage: ./unreleased.sh <revision range>"
+    echo >&2 "Prints all changelog entries added by the given revision range"
+    echo >&2 "For info about <revision range> please see gitrevisions(7)"
+    exit 64
+fi
+
 for SHA in $(git log --format=%H "$1"); do
   git show --quiet --format=%b "$SHA" \
     | awk '/^$/{next} toupper($0) ~ /CHANGELOG_END/{flag=0; next} toupper($0) ~ /CHANGELOG_BEGIN/{flag=1; next} flag'