error message

main.c

@@ -13,11 +13,14 @@ int get_alias(Alias *alias, State *state, char *name) {
     return ER_FAILURE;
 }
 
+int del_alias(State *state, char *name); 
+
 int add_alias(State* state, char *name, char *substitution) {
     Alias alias;
     strip_char(name, ' ');
     alias.name = calloc(strlen(name) + 1, sizeof(char));
     alias.substitution = calloc(strlen(substitution) + 1, sizeof(char));
+
     strcpy(alias.name, name);
     strcpy(alias.substitution, substitution);
     Alias throw;
@@ -27,6 +30,11 @@ int add_alias(State* state, char *name, char *substitution) {
 
         state->aliases[state->num_aliases] = alias;
         state->num_aliases++;
+    } else {
+        del_alias(state, name);
+        free(alias.name);
+        free(alias.substitution);
+        add_alias(state, name, substitution);
     }
 
     return ER_SUCCESS;

run.c

@@ -23,6 +23,9 @@ int execute(FILE *in, FILE *out, char *args[], pid_t* child_ID) {
         dup2(out_FD, 1);
 
         err = execvp(args[0], args);
+        if (err) {
+            perror("Bad");
+        }
     }
 
     return ER_SUCCESS;