diff --git a/tests/functional/flakes/non-flake-inputs.sh b/tests/functional/flakes/non-flake-inputs.sh
index 66dc74e0c..c9c9803d3 100644
--- a/tests/functional/flakes/non-flake-inputs.sh
+++ b/tests/functional/flakes/non-flake-inputs.sh
@@ -71,7 +71,7 @@ nix build -o "$TEST_ROOT/result" "$flake3Dir#sth" --commit-lock-file
 nix registry add --registry "$registry" flake3 "git+file://$flake3Dir"
 
 nix build -o "$TEST_ROOT/result" flake3#fnord
-[[ $(cat $TEST_ROOT/result) = FNORD ]]
+[[ $(cat "$TEST_ROOT/result") = FNORD ]]
 
 # Check whether flake input fetching is lazy: flake3#sth does not
 # depend on flake2, so this shouldn't fail.
diff --git a/tests/functional/flakes/shebang.sh b/tests/functional/flakes/shebang.sh
index 645b1fa38..576a62e2c 100644
--- a/tests/functional/flakes/shebang.sh
+++ b/tests/functional/flakes/shebang.sh
@@ -6,7 +6,7 @@ TODO_NixOS
 
 createFlake1
 
-scriptDir=$TEST_ROOT/nonFlake
+scriptDir="$TEST_ROOT/nonFlake"
 mkdir -p "$scriptDir"
 
 cat > "$scriptDir/shebang.sh" <<EOF
@@ -20,10 +20,8 @@ echo "\$@"
 EOF
 chmod +x "$scriptDir/shebang.sh"
 
-#git -C "$scriptDir" add shebang.sh
-
 # this also tests a fairly trivial double backtick quoted string, ``--command``
-cat > $scriptDir/shebang-comments.sh <<EOF
+cat > "$scriptDir/shebang-comments.sh" <<EOF
 #! $(type -P env) nix
 # some comments
 # some comments
@@ -33,9 +31,9 @@ cat > $scriptDir/shebang-comments.sh <<EOF
 #! nix --no-write-lock-file ``--command`` bash
 foo
 EOF
-chmod +x $scriptDir/shebang-comments.sh
+chmod +x "$scriptDir/shebang-comments.sh"
 
-cat > $scriptDir/shebang-different-comments.sh <<EOF
+cat > "$scriptDir/shebang-different-comments.sh" <<EOF
 #! $(type -P env) nix
 # some comments
 // some comments
@@ -51,9 +49,9 @@ cat > $scriptDir/shebang-different-comments.sh <<EOF
 #! nix --no-write-lock-file --command cat
 foo
 EOF
-chmod +x $scriptDir/shebang-different-comments.sh
+chmod +x "$scriptDir/shebang-different-comments.sh"
 
-cat > $scriptDir/shebang-reject.sh <<EOF
+cat > "$scriptDir/shebang-reject.sh" <<EOF
 #! $(type -P env) nix
 # some comments
 # some comments
@@ -63,12 +61,12 @@ cat > $scriptDir/shebang-reject.sh <<EOF
 #! nix --no-write-lock-file --command bash
 foo
 EOF
-chmod +x $scriptDir/shebang-reject.sh
+chmod +x "$scriptDir/shebang-reject.sh"
 
-cat > $scriptDir/shebang-inline-expr.sh <<EOF
+cat > "$scriptDir/shebang-inline-expr.sh" <<EOF
 #! $(type -P env) nix
 EOF
-cat >> $scriptDir/shebang-inline-expr.sh <<"EOF"
+cat >> "$scriptDir/shebang-inline-expr.sh" <<"EOF"
 #! nix --offline shell
 #! nix --impure --expr ``
 #! nix let flake = (builtins.getFlake (toString ../flake1)).packages;
@@ -81,18 +79,18 @@ set -ex
 foo
 echo "$@"
 EOF
-chmod +x $scriptDir/shebang-inline-expr.sh
+chmod +x "$scriptDir/shebang-inline-expr.sh"
 
-cat > $scriptDir/fooScript.nix <<"EOF"
+cat > "$scriptDir/fooScript.nix" <<"EOF"
 let flake = (builtins.getFlake (toString ../flake1)).packages;
     fooScript = flake.${builtins.currentSystem}.fooScript;
  in fooScript
 EOF
 
-cat > $scriptDir/shebang-file.sh <<EOF
+cat > "$scriptDir/shebang-file.sh" <<EOF
 #! $(type -P env) nix
 EOF
-cat >> $scriptDir/shebang-file.sh <<"EOF"
+cat >> "$scriptDir/shebang-file.sh" <<"EOF"
 #! nix --offline shell
 #! nix --impure --file ./fooScript.nix
 #! nix --no-write-lock-file --command bash
@@ -100,12 +98,12 @@ set -ex
 foo
 echo "$@"
 EOF
-chmod +x $scriptDir/shebang-file.sh
+chmod +x "$scriptDir/shebang-file.sh"
 
-[[ $($scriptDir/shebang.sh) = "foo" ]]
-[[ $($scriptDir/shebang.sh "bar") = "foo"$'\n'"bar" ]]
-[[ $($scriptDir/shebang-comments.sh ) = "foo" ]]
-[[ "$($scriptDir/shebang-different-comments.sh)" = "$(cat $scriptDir/shebang-different-comments.sh)" ]]
-[[ $($scriptDir/shebang-inline-expr.sh baz) = "foo"$'\n'"baz" ]]
-[[ $($scriptDir/shebang-file.sh baz) = "foo"$'\n'"baz" ]]
-expect 1 $scriptDir/shebang-reject.sh 2>&1 | grepQuiet -F 'error: unsupported unquoted character in nix shebang: *. Use double backticks to escape?'
+[[ $("$scriptDir/shebang.sh") = "foo" ]]
+[[ $("$scriptDir/shebang.sh" "bar") = "foo"$'\n'"bar" ]]
+[[ $("$scriptDir/shebang-comments.sh" ) = "foo" ]]
+[[ "$("$scriptDir/shebang-different-comments.sh")" = "$(cat "$scriptDir/shebang-different-comments.sh")" ]]
+[[ $("$scriptDir/shebang-inline-expr.sh" baz) = "foo"$'\n'"baz" ]]
+[[ $("$scriptDir/shebang-file.sh" baz) = "foo"$'\n'"baz" ]]
+expect 1 "$scriptDir/shebang-reject.sh" 2>&1 | grepQuiet -F 'error: unsupported unquoted character in nix shebang: *. Use double backticks to escape?'