diff --git a/src/hashset.c b/src/hashset.c
index d5c0891..8f80fec 100644
--- a/src/hashset.c
+++ b/src/hashset.c
@@ -69,7 +69,7 @@ int hashset_put(HashSet * hs, const char *key, void *value) {
 }
 
 int hashset_add(HashSet * hs, const char *key) {
-	return hashset_put(hs, key, NULL);
+	return hashset_put(hs, key, "nil");
 }
 
 int hashset_size(const HashSet * hs) {
diff --git a/src/hstr_history.c b/src/hstr_history.c
index b3b6978..22bb1e4 100644
--- a/src/hstr_history.c
+++ b/src/hstr_history.c
@@ -23,7 +23,7 @@ typedef struct {
 
 static HistoryItems *prioritizedHistory;
 static bool dirty;
-static const char *commandBlacklist[] = {"ls", "pwd", "cd", "hh"};
+static const char *commandBlacklist[] = {"ls", "pwd", "cd", "hh", "mc"};
 
 #ifdef DEBUG_RADIX
 #define DEBUG_RADIXSORT() radixsort_stat(&rs); exit(0)