--- a/util.h	Sun Mar 19 18:32:49 2017 -0700
+++ b/util.h	Tue Mar 21 00:40:25 2017 -0700
@@ -21,6 +21,8 @@
 char * alloc_concat(char const * first, char const * second);
 //Allocates a new string containing the concatenation of the strings pointed to by parts
 char * alloc_concat_m(int num_parts, char const ** parts);
+//Returns a newly allocated string in which all variables in based are replaced with values from vars or the environment
+char *replace_vars(char *base, tern_node *vars, uint8_t allow_env);
 //Byteswaps a ROM image in memory
 void byteswap_rom(int filesize, uint16_t *cart);
 //Returns the size of a file using fseek and ftell