diff --git a/src/libutil/file-system.cc b/src/libutil/file-system.cc
index 14d496958..cf8a6d967 100644
--- a/src/libutil/file-system.cc
+++ b/src/libutil/file-system.cc
@@ -116,7 +116,11 @@ Path canonPath(PathView path, bool resolveSymlinks)
         }
     }
 
-    return s.empty() ? "/" : std::move(s);
+    if (s.empty()) {
+        s = "/";
+    }
+
+    return s;
 }
 
 
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 6e47ce2a3..8f310c6fe 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -122,12 +122,11 @@ bool hasSuffix(std::string_view s, std::string_view suffix)
 }
 
 
-std::string toLower(const std::string & s)
+std::string toLower(std::string s)
 {
-    std::string r(s);
-    for (auto & c : r)
+    for (auto & c : s)
         c = std::tolower(c);
-    return r;
+    return s;
 }
 
 
@@ -135,7 +134,7 @@ std::string shellEscape(const std::string_view s)
 {
     std::string r;
     r.reserve(s.size() + 2);
-    r += "'";
+    r += '\'';
     for (auto & i : s)
         if (i == '\'') r += "'\\''"; else r += i;
     r += '\'';
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 27faa4d6d..11a0431da 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -180,7 +180,7 @@ bool hasSuffix(std::string_view s, std::string_view suffix);
 /**
  * Convert a string to lower case.
  */
-std::string toLower(const std::string & s);
+std::string toLower(std::string s);
 
 
 /**