diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index a7cbfbfd0..6d178dfe5 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -132,7 +132,7 @@ static std::string indent(std::string_view indentFirst, std::string_view indentR
 /**
  * A development aid for finding missing positions, to improve error messages. Example use:
  *
- *     NIX_DEVELOPER_SHOW_UNKNOWN_LOCATIONS=1 _NIX_TEST_ACCEPT=1 make tests/lang.sh.test
+ *     NIX_DEVELOPER_SHOW_UNKNOWN_LOCATIONS=1 _NIX_TEST_ACCEPT=1 just test --suite installcheck -v functional-lang
  *     git diff -U20 tests
  *
  */
diff --git a/tests/functional/lang.sh b/tests/functional/lang.sh
index 59db10340..ca54fb88d 100755
--- a/tests/functional/lang.sh
+++ b/tests/functional/lang.sh
@@ -155,7 +155,7 @@ else
         echo ''
         echo 'You can rerun this test with:'
         echo ''
-        echo '    _NIX_TEST_ACCEPT=1 make tests/functional/lang.sh.test'
+        echo '    _NIX_TEST_ACCEPT=1 just test --suite installcheck -v functional-lang'
         echo ''
         echo 'to regenerate the files containing the expected output,'
         echo 'and then view the git diff to decide whether a change is'