git-merge: show usage if run without arguments

diff --git a/templates/hooks--commit-msg b/templates/hooks--commit-msg
index 643822d2351c4547895237992400bd92f492085b..0b906caa98f3d4deced75d196d969d7216d31961 100644 (file)
--- a/templates/hooks--commit-msg
+++ b/templates/hooks--commit-msg
@@ -11,4 +11,8 @@
 # This example catches duplicate Signed-off-by lines.
 
 test "" = "$(grep '^Signed-off-by: ' "$1" |
-        sort | uniq -c | sed -e '/^[   ]*1 /d')"
+        sort | uniq -c | sed -e '/^[   ]*1[    ]/d')" || {
+       echo >&2 Duplicate Signed-off-by lines.
+       exit 1
+}
+