Add original unix v6

source/s1/echo.c

@@ -0,0 +1,10 @@
+main(argc, argv)
+int argc;
+char *argv[];
+{
+	int i;
+
+	argc--;
+	for(i=1; i<=argc; i++)
+		printf("%s%c", argv[i], i==argc? '\n': ' ');
+}