diff --git a/src/Makefile b/src/Makefile
index cd6280c..8f2217d 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -25,8 +25,7 @@ endif
 PROGS = main
 
 ## HWLOC_XML_VERBOSE=1
-## HWLOC_XMLFILE=topo-xml/lassen-hw2.xml
-## ./mpibind_v0.14.1
+## HWLOC_XMLFILE=../topo-xml/coral-lassen.xml ./main
 
 all: $(PROGS) $(MPIBIND_SONAME) $(MPIBIND_LIB)
 
diff --git a/src/mpibind.c b/src/mpibind.c
index 64038a4..63e58b3 100644
--- a/src/mpibind.c
+++ b/src/mpibind.c
@@ -1389,7 +1389,7 @@ void mpibind_print_mapping(mpibind_t *handle)
  */
 int mpibind_set_env_vars(mpibind_t *handle)
 {
-  int i, v, nc, val;
+  int i, v, nc, val, end;
   char *str;
   int nvars = 4;
   char *vars[] = {"OMP_NUM_THREADS",
@@ -1445,11 +1445,16 @@ int mpibind_set_env_vars(mpibind_t *handle)
 	  nc += snprintf(str+nc, LONG_STR_SIZE-nc, "%d,", val); 
 	} hwloc_bitmap_foreach_end();
       }
+      
+      /* Strip the last comma */
+      end = strlen(str) - 1; 
+      if (str[end] == ',')
+	str[end] = '\0'; 
     } 
   }
 
   /* Store the names of the vars in its own array
-     so that callers can retrieve it easily */
+     so that callers can retrieve them easily */
   handle->names = calloc(nvars, sizeof(char *)); 
   for (v=0; v<nvars; v++) {
     handle->names[v] = malloc(SHORT_STR_SIZE);