diff --git a/cameo/cameo.c b/cameo/cameo.c
index 001ff7c..6f4ed48 100644
--- a/cameo/cameo.c
+++ b/cameo/cameo.c
@@ -21,14 +21,33 @@
 #include "gerber.h"
 
 
+extern int yyparse(void);
+extern FILE *yyin;
+
+
+static void run_script(const char *file)
+{
+
+	if (file) {
+		yyin = fopen(file, "r");
+		if (!yyin) {
+			perror(file);
+			exit(1);
+		}
+	}
+	yyparse();
+}
+
+
 static void usage(const char *name)
 {
 	fprintf(stderr,
 "usage: %s [-d] r_mm [in.gnuplot [out.gnuplot]]\n"
-"       %s -g [-d] r_mm [in.gerber [out.gnuplot]]\n\n"
+"       %s -g [-d] r_mm [in.gerber [out.gnuplot]]\n"
+"       %s [script]\n\n"
 "  -d  put a dog-bone notch in each concave external corner\n"
 "  -g  input format is KiCad Gerber, not gnuplot\n"
-    , name, name);
+    , name, name, name);
 	exit(1);
 }
 
@@ -36,6 +55,7 @@ static void usage(const char *name)
 int main(int argc, char **argv)
 {
 	char *in = NULL, *out = NULL;
+	char *end;
 	int gerber = 0, dog_bone = 0;
 	double r;
 	struct path *paths;
@@ -61,8 +81,17 @@ int main(int argc, char **argv)
 		in = argv[optind+1];
 		/* fall through */
 	case 1:
-		r = atof(argv[optind]);
+		r = strtod(argv[optind], &end);
+		if (*end) {
+			if (argc-optind != 1)
+				usage(*argv);
+			run_script(argv[optind]);
+			return 0;
+		}
 		break;
+	case 0:
+		run_script(NULL);
+		return 0;
 	default:
 		usage(*argv);
 	}