diff --git a/make-changelog b/make-changelog
index 48e0431..23c4e3d 100755
--- a/make-changelog
+++ b/make-changelog
@@ -9,8 +9,8 @@
 # Find the years covered by the generated ChangeLog, so that
 # a proper copyright notice can be output.
 years=$(sed -n 's/^\([0-9][0-9]*\).*/\1/p' ChangeLog | sort -nu)
-start_year=$(echo "$years" | head)
-end_year=$(echo "$years" | tail)
+start_year=$(echo "$years" | head -1)
+end_year=$(echo "$years" | tail -1)
 
 if test "$start_year" = "$end_year"; then
   year_range=$start_year