diff --git a/tests/df/df-output.sh b/tests/df/df-output.sh
index 6c5fe3c7b..de062ee78 100755
--- a/tests/df/df-output.sh
+++ b/tests/df/df-output.sh
@@ -125,7 +125,7 @@ compare exp out2 || fail=1
 
 # Ensure that --output is mentioned in the usage.
 df --help > out || fail=1
-grep ' --output' out >/dev/null || { fail=1; cat out; }
+grep -- '--output' out >/dev/null || { fail=1; cat out; }
 
 # Ensure that the FILE field contains the argument.
 cat <<\EOF > exp || framework_failure_
diff --git a/tests/du/inodes.sh b/tests/du/inodes.sh
index 2af229725..1d2dcd13e 100755
--- a/tests/du/inodes.sh
+++ b/tests/du/inodes.sh
@@ -136,5 +136,5 @@ grep ' ineffective ' err >/dev/null || { fail=1; cat out err; }
 
 # Ensure that --inodes is mentioned in the usage.
 du --help > out || fail=1
-grep ' --inodes ' out >/dev/null || { fail=1; cat out; }
+grep -- '--inodes' out >/dev/null || { fail=1; cat out; }
 Exit $fail