diff --git a/Makefile b/Makefile
index 85b2a7ba..a0e8e819 100644
--- a/Makefile
+++ b/Makefile
@@ -357,7 +357,7 @@ uninstall:
 #################
 
 format:
-	tools/format.sh
+	sh tools/format.sh
 
 grammar: build/janet.tmLanguage
 build/janet.tmLanguage: tools/tm_lang_gen.janet $(JANET_TARGET)
diff --git a/src/core/value.c b/src/core/value.c
index 3a071cda..ed66ee11 100644
--- a/src/core/value.c
+++ b/src/core/value.c
@@ -703,7 +703,7 @@ Janet janet_lengthv(Janet x) {
                 return janet_wrap_number(len);
 #else
                 if (len < (size_t) JANET_INTMAX_INT64) {
-                    return janet_wrap_number(len);
+                    return janet_wrap_number((double) len);
                 } else {
                     janet_panicf("integer length %u too large", len);
                 }
diff --git a/tools/format.sh b/tools/format.sh
old mode 100755
new mode 100644
index 37e03f26..57c568cd
--- a/tools/format.sh
+++ b/tools/format.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/usr/bin/env sh
 
 # Format all code with astyle