diff --git a/runtime/ikarus b/runtime/ikarus
index 2844b2b..e179f43 100755
Binary files a/runtime/ikarus and b/runtime/ikarus differ
diff --git a/runtime/ikarus-main.c b/runtime/ikarus-main.c
index 9345ca1..e299b7e 100644
--- a/runtime/ikarus-main.c
+++ b/runtime/ikarus-main.c
@@ -10,11 +10,57 @@
 #include <errno.h>
 #include <gmp.h>
 
+/* get_option
+   
+   takes pointers to argc and argv and looks for the first
+   option matching opt.  If one exists, it removes it from the argv
+   list, updates argc, and returns a pointer to the option value.
+   returns null if option is not found.
+   */
+char* 
+get_option(char* opt, int argc, char** argv){
+  int i;
+  for(i=1; i<argc; i++){
+    if(strcmp(opt, argv[i]) == 0){
+      if((i+1) < argc){
+        char* rv = argv[i+1];
+        int j;
+        for(j=i+2; j<argc; j++, i++){
+          argv[i] = argv[j];
+        }
+        return rv;
+      } 
+      else {
+        fprintf(stderr, "Error: option %s not provided\n", opt);
+        exit(-1);
+      }
+    }
+    else if(strcmp("--", argv[i]) == 0){
+      return 0;
+    }
+  }
+  return 0;
+}
+
+
 int main(int argc, char** argv){
-  if(argc < 2){
-    fprintf(stderr, "insufficient arguments\n");
+  char ikarus_boot[FILENAME_MAX];
+  char* boot_file = get_option("-b", argc, argv);
+  if(boot_file){
+    argc -= 2;
+  } else {
+    boot_file = ikarus_boot;
+    char* x = ikarus_boot;
+    x = stpcpy(x, argv[0]);
+    x = stpcpy(x, ".boot");
+  }
+  if(argc != 1){
+    fprintf(stderr,
+        "Error ~s: unrecognized argument %s\n",
+        argv[0], argv[1]);
     exit(-1);
   }
+
   if(sizeof(mp_limb_t) != sizeof(int)){
     fprintf(stderr, "ERROR: limb size\n");
   }
@@ -22,11 +68,7 @@ int main(int argc, char** argv){
     fprintf(stderr, "ERROR: bits_per_limb=%d\n", mp_bits_per_limb);
   }
   ikpcb* pcb = ik_make_pcb();
-  int i;
-  for(i=1; i<argc; i++){
-    char* fasl_file = argv[i];
-    ik_fasl_load(pcb, fasl_file);
-  }
+  ik_fasl_load(pcb, boot_file);
   /*
   fprintf(stderr, "collect time: %d.%03d utime, %d.%03d stime (%d collections)\n", 
                   pcb->collect_utime.tv_sec, 
diff --git a/src/Makefile b/src/Makefile
index c4847d2..6f982e3 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -3,7 +3,7 @@ all: ikarus.boot
 
 ikarus.boot: *.ss
 	cp ikarus.boot ikarus.boot.back
-	echo '(load "makefile.ss")' | time ../runtime/ikarus ikarus.boot
+	echo '(load "makefile.ss")' | time ../runtime/ikarus -b ikarus.boot
 
 clean:
 	rm -f *.fasl
diff --git a/src/ikarus.boot b/src/ikarus.boot
index e96991d..bfe3a4c 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.boot.back b/src/ikarus.boot.back
deleted file mode 100644
index 779e8d5..0000000
Binary files a/src/ikarus.boot.back and /dev/null differ